ESTRO 2021 Abstract Book

Optimal radiotherapy for al 27-31August2021 ONSITEINMADRID,SPAIN&ONLINE

Radiotherapy &Oncology Journal of the European SocieTy for Radiotherapy and Oncology

Volume 161 Supplement 1 (2021)

Radiotherapy & Oncology is available online: For ESTRO members: http://www.thegreenjournal.com For institutional libraries: http://www.sciencedirect.com

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ESTRO 2021 27 - 31 August 2021 ONSITE IN MADRID, SPAIN & ONLINE

Table of contents

SATURDAY 28 AUGUST 2021

Teaching lecture Multidisciplinary research in Europe....................................................................................................................... (abs. 2 - 3) The microbiome: Its role in cancer development and treatment response............................................................. (abs. 4) Breast reconstruction and radiotherapy...................................................................................................................... (abs. 5) Neurocognitive changes following radiotherapy for primary brain tumours..................................................... (abs. 6 - 7) Independent dose calculation and pre-treatment patient specific QA..................................................................... (abs. 8) Diffusion MRI: How to get started................................................................................................................................. (abs. 9) The role of RTT leadership in advancing multi-disciplinary research..................................................................... (abs. 10) New developments In skin cancers treatment: is brachytherapy the new frontier especially for the face?...... (abs. 11) Symposium Education in radiation oncology..........................................................................................................................(abs. 12 - 15) Joint symposium ESTRO-EACR: How does cancer cell metabolism affect the radiation response and vice versa?..................(abs. 16 - 19) Symposium New endpoints for early breast cancer - Less is more?.....................................................................................(abs. 20 - 23) Radiosurgery for central nervous system disorders: Beyond glioblastoma and metastases.......................(abs. 24 - 27) Clinical implementation of in vivo dosimetry.....................................................................................................(abs. 28 - 30) Joint symposium ESTRO-AAPM: A roadmap for the use of quantitative imaging in radiation oncology...................................(abs. 31 - 34) Symposium RTT-led radiomics research..................................................................................................................................(abs. 35 - 37) Debate Prostate cancer: Short treatments by SBRT or brachytherapy?.......................................................................(abs. 38 - 40) Poster highlights Poster Highlights 1: Treatment planning 1.........................................................................................................(abs. 41 - 47) Poster Highlights 2: Head and neck 1.................................................................................................................(abs. 48 - 54) Proffered papers Proffered papers 1: Health services and health economics. ............................................................................(abs. 55 - 60) Proffered Papers 2: Tumour microenvironment................................................................................................(abs. 61 - 66) Proffered papers 3: Breast...................................................................................................................................(abs. 67 - 72) Proffered papers 4: CNS.......................................................................................................................................(abs. 73 - 78) Proffered Papers 5: Applied dosimetry...............................................................................................................(abs. 79 - 84) Proffered Papers 6: Adaptive RT: MR-guided and SBRT....................................................................................(abs. 85 - 90) Proffered Papers 7: Advances in RT imaging and contouring...........................................................................(abs. 91 - 96) Symposium Highlights of WCB 2021. .....................................................................................................................................(abs. 97 - 102)

Poster highlights Poster Highlights 3: Outcome modelling.......................................................................................................(abs. 103 - 109) Poster Highlights 4: Lower GI (colon, rectum, anus)......................................................................................(abs. 110 - 116) Plenary session Presidential symposium - Optimal radiotherapy for all................................................................................(abs. 117 - 121) Symposium Guidelines..........................................................................................................................................................(abs. 122 - 129) Radiobiology underpinning the interactions between radiotherapy and the anti-tumour immune response.............................................................................................................................................(abs. 130 - 133) Debate Should the majority of radiation treatments after breast conserving surgery consist of maximum 5 fractions?... (abs. 134 - 138) Joint symposium ESTRO-CARO: COVID-19....................................................................................................................................(abs. 139 - 143) Symposium Proton arc therapy - An evolution or revolution?...........................................................................................(abs. 144 - 146) The use of MR in radiotherapy.........................................................................................................................(abs. 147 - 149) What’s next for breathing motion management in radiotherapy?...............................................................(abs. 150 - 152) Joint symposium ESTRO-ESGO - State of the Art: Updated ESGO-ESTRO-ESP guidelines in endometrial cancer.................(abs. 153 - 158) Poster highlights Poster Highlights 5: Advanced radiotherapy service implementation.........................................................(abs. 159 - 164) Poster Highlights 6: CNS 1................................................................................................................................(abs. 165 - 171) Award lecture E van der Schueren Award. ..............................................................................................................................(abs. 172 - 173) Jens Overgaard Legacy Award..........................................................................................................................(abs. 174 - 175) Proffered papers Proffered papers 8: Patient-reported outcome measures & quality of life.................................................(abs. 176 - 181) Proffered Papers 9: Radiation immune effects..............................................................................................(abs. 182 - 187) Proffered papers 10: Lung................................................................................................................................(abs. 188 - 193) Proffered papers 11: Detectors and dosimetry..............................................................................................(abs. 194 - 199) Proffered papers 12: Adaptive RT: Proton......................................................................................................(abs. 200 - 205) Proffered papers 13: Haematology / Paediatrics / Sarcoma.........................................................................(abs. 206 - 211) Poster highlights Poster Highlights 7: Quantitative functional and biological imaging...........................................................(abs. 212 - 218) Poster Highlights 8: Breast...............................................................................................................................(abs. 219 - 225)

SUNDAY 29 AUGUST 2021

Teaching Lecture Biomarker-guided precision radiotherapy............................................................................................................... (abs. 226) The radiobiology of the normal brain...................................................................................................................... (abs. 227) Shifting cold to hot tumors: Interplay between radiation, cancer cells and microenvironment........................ (abs. 228) How to tailor your cervical cancer treatment based on evidence-based dose-effect relationships.........(abs. 229 - 230) IAEA TRS 398: Update for modern radiotherapy..................................................................................................... (abs. 231) The dos and don’ts for statistical treatment outcome modelling......................................................................... (abs. 232) The future of RTT advanced practice........................................................................................................................ (abs. 233) Symposium Turning cold into hot tumours: Challenges in radio-immunotherapy.........................................................(abs. 234 - 236) Normal tissue effects of combined therapies................................................................................................(abs. 237 - 240)

Joint symposium ESTRO-RANZCR - Challenges and benefits of SBRT........................................................................................(abs. 241 - 244) ESTRO-ESR: MRI-guided radiotherapy in gynaecological cancer treatment................................................(abs. 245 - 248) ESTRO-EFOMP: New radiotherapy technology - What does it mean for radioprotection..........................(abs. 249 - 252)

Symposium Novel planning approaches for uncertanties in GTV delineation a

nd microscopic disease around GTVs. ............................................................................................................(abs. 253 - 255) Opportunities for RTTs in higher education: Making the right choice.........................................................(abs. 256 - 258) Salvage brachytherapy for breast cancer.......................................................................................................(abs. 259 - 262) Poster highlights Poster highlights 9: Intra-fraction motion management...............................................................................(abs. 263 - 269) Poster Highlights 10: Lung................................................................................................................................(abs. 270 - 276) Proffered papers Proffered papers 14: Hypoxia and tumour microenvironment...................................................................(abs. 277 - 282) Proffered papers 15: Radiobiology of normal tissues...................................................................................(abs. 283 - 288) Proffered papers 16: Late-breaking abstracts................................................................................................(abs. 289 - 294) Proffered papers 17: Gynaecological..............................................................................................................(abs. 295 - 300) Proffered papers 18: Training and implementation for new technologies.................................................(abs. 301 - 306) Proffered papers 19: Plan optimisation and algorithms...............................................................................(abs. 307 - 312) Proffered papers 20: Education and training.................................................................................................(abs. 313 - 318) Poster highlights Poster highlights 11: Dosimetry 1....................................................................................................................(abs. 319 - 325) Poster highlights 12: Miscellaneous................................................................................................................(abs. 326 - 332) Proffered papers Highlights of Proffered Papers - Latest Clinical Trials....................................................................................(abs. 333 - 338) Joint symposium ESTRO-JASTRO - Current status of hyperthermia in radiation oncology......................................................(abs. 339 - 344) Symposium Novel model systems for radiobiology research............................................................................................(abs. 345 - 348) Multiple and multifocal SBRT in advanced disease........................................................................................(abs. 349 - 352) Update in advanced breast cancer..................................................................................................................(abs. 353 - 356) Proffered papers Proffered papers 21: Motion management....................................................................................................(abs. 357 - 364) Symposium Automatic contouring: Metrics and clinical evaluation approaches............................................................(abs. 365 - 368) Working with infections/contagious pateitns - COVID-19.............................................................................(abs. 369 - 371) Next generation of brachytherapy treatment planning systems: What do we want and what do they need?.....................................................................................................(abs. 372 - 374) Poster highlights Poster highlights 13: Treatment planning 2....................................................................................................(abs. 375 - 381) Poster highlights 14: Head and neck 2............................................................................................................(abs. 382 - 388) Award lecture C Regaud Award................................................................................................................................................(abs. 389 - 390) Iridium Award....................................................................................................................................................(abs. 391 - 392) Proffered papers Proffered papers 22: Functional and biological imaging...............................................................................(abs. 393 - 398) Proffered papers 23: Radiation response and biomarkers...........................................................................(abs. 399 - 404) Proffered papers 24: Palliation........................................................................................................................(abs. 405 - 410) Proffered papers 25: Upper GI.........................................................................................................................(abs. 411 - 416) Proffered papers 26: Treatment planning for proton therapy.....................................................................(abs. 417 - 422) Proffered papers 27: Large-scale assurance of quality.................................................................................(abs. 423 - 428) Poster highlights Poster highlights 15: Image-guided innovations in radiotherapy. ...............................................................(abs. 429 - 434) Poster highlights 16: Radiobiology..................................................................................................................(abs. 435 - 441) Poster highlights 17: Gynaecological...............................................................................................................(abs. 442 - 448)

MONDAY 30 AUGUST 2021

Teaching Lecture Stem cells in radiation oncology............................................................................................................................... (abs. 449) The microbiome: An emerging concept impacting the tumour and normal tissue with implications for treatment personalisation..................................................................................................... (abs. 450) Which techniques and delineation for craniospinal irradiation?........................................................................... (abs. 451) Treatment plan quality assessment......................................................................................................................... (abs. 452) Respiratory motion interventions for high precision radiotherapy...................................................................... (abs. 453) Evidence-based approach for optimising clinical processes in radiotherapy...................................................... (abs. 454) Mental health prevention - Tips to stay healthy, recognise the signs of burnout............................................... (abs. 455) Joint symposium ESTRO-ASTRO: FLASH radiotherapy from a multidisciplinary prospective..................................................(abs. 456 - 459) Symposium Salvage treatment for radiotherapy-recurrent primary prostate cancer....................................................(abs. 460 - 463) New developments in head and neck cancer radiotherapy. ........................................................................(abs. 464 - 466) Proffered papers Proffered papers 28: Automated planning.....................................................................................................(abs. 467 - 474) Symposium The role of deep learning in CBCT-based workflows.....................................................................................(abs. 475 - 480) Innovations in radiotherapy practice..............................................................................................................(abs. 481 - 483) Mobility/Grant reports......................................................................................................................................(abs. 484 - 488) Poster highlights Poster Highlights 18: Radiotherapy treatment outcome...............................................................................(abs. 489 - 494) Poster Highlights 19: Upper GI.........................................................................................................................(abs. 495 - 501) Proffered papers Proffered papers 29: New technologies..........................................................................................................(abs. 502 - 507) Proffered papers 30: Urology...........................................................................................................................(abs. 508 - 513) Proffered papers 31: Head and neck...............................................................................................................(abs. 514 - 519) Proffered papers 32: Image acquisition and processing...............................................................................(abs. 520 - 525) Proffered papers 33: Outcome modelling 1...................................................................................................(abs. 526 - 531) Proffered papers 34: Image-guided radiotherapy and treatment verification...........................................(abs. 532 - 537) Symposium Make the best use of online resources and meetings for remote (net)working.........................................(abs. 538 - 542) Poster highlights Poster Highlights 20: Treatment and planning evaluation............................................................................(abs. 543 - 549) Poster Highlights 21: Hyperthermia................................................................................................................(abs. 550 - 556) Proffered papers Highlights of proffered papers - Best Papers and Paper Awards.................................................................(abs. 557 - 562) Young lunch symposium + networking Diversity, Equity and Inclusion.........................................................................................................................(abs. 563 - 565) Symposium State-of-the-art in lung cancer.........................................................................................................................(abs. 566 - 569) Debate Rectal spacers for prostate radiotherapy - The farther the better?.............................................................(abs. 570 - 574) Symposium New opportunities for radio-immunotherapy in head and neck cancer.....................................................(abs. 575 - 577) Next steps in automated treatment planning................................................................................................(abs. 578 - 580) Image guidance in particle therapy: From state-of-the-art towards real-time ART....................................(abs. 581 - 584) Debate This house believes that in the next 5 years the current RTT education curriculum will be obsolete.....(abs. 585 - 589)

Symposium Project from A to Z in a hot or new topic Where do you start? And how to publish?. ...............................(abs. 590 - 594) Poster highlights Poster Highlights 22: Dosimetry 2...................................................................................................................(abs. 595 - 601) Poster Highlights 23: CNS 2..............................................................................................................................(abs. 602 - 608) Award lecture K Breur Award....................................................................................................................................................(abs. 609 - 610) Honorary Physicist Award. ...............................................................................................................................(abs. 611 - 612) Proffered papers Proffered papers 35: Adaptive radiotherapy..................................................................................................(abs. 613 - 618) Proffered papers 36: Lower GI.........................................................................................................................(abs. 619 - 624) Proffered papers 37: Immuno and targeted agents......................................................................................(abs. 625 - 630) Proffered papers 38: Treatment planning: applications...............................................................................(abs. 631 - 636) Proffered papers 39: Outcome modelling 2...................................................................................................(abs. 637 - 642) Proffered papers 40: Advances in RT planning..............................................................................................(abs. 643 - 648) Poster highlights Poster Highlights 24: Imaging acquisition and processing............................................................................(abs. 649 - 655) Poster Highlights 25: Prostate..........................................................................................................................(abs. 656 - 662) Teaching Lecture The 4 Rs of radiobiology revisited in hypofractionated radiotherapy.................................................................. (abs. 663) Clinical need vs technology push in innovation...................................................................................................... (abs. 664) Multi-modality treatment of soft tissue sarcoma. .................................................................................................. (abs. 665) Distracting techniques for paediatric/AYA/adult radiotherapy............................................................................. (abs. 666) The medical device regulation and its implications for (your own) medical hard and software........................ (abs. 667) Physics perspective of stereotactic cardiac ablation.............................................................................................. (abs. 668) Health literacy: The cornerstone of the patient’s understanding of radiotherapy.............................................. (abs. 669) Symposium RBE in proton therapy.......................................................................................................................................(abs. 670 - 673) Surface-guided radiotherapy...........................................................................................................................(abs. 674 - 676) Debate Is it primetime for stereotactic radiotherapy for localised high-risk prostate cancer?..............................(abs. 677 - 681) Symposium Radiotherapy in oesophageal cancer..............................................................................................................(abs. 682 - 684) Debate Hype or Hope? This house believes that the application of radiomics will significantly improve clinical outcome of radiotherapy by 2025...........................................................(abs. 685 - 689) Symposium COVID-19: Lessons learned from a medical physics perspective.................................................................(abs. 690 - 694) The use of telehealth in radiotherapy.............................................................................................................(abs. 695 - 697) State-of-the-art in prostate cancer..................................................................................................................(abs. 698 - 700) MR Linacs - Do we really know what are we doing?.......................................................................................(abs. 701 - 703) The evolving role of elective nodal irradiation in 2021 in head and neck, lung, breast and prostate cancer..........................................................................................................................................(abs. 704 - 707) Recent developments in the treatment of rectal cancer...............................................................................(abs. 708 - 711) Proving the clinical benefit of 15 years of IGRT..............................................................................................(abs. 712 - 716) Novel technology for treatment delivery and modulation: Flash, microbeams and spatio-temporal fractionation..................................................................................................................(abs. 717 - 720) The impact of immoblisation/positioning in advanced radiotherapy..........................................................(abs. 721 - 723)

TUESDAY 31 AUGUST 2021

POSTER DISCUSSIONS

Poster discussion 1: Breast. .............................................................................................................................(abs. 728 - 733) Poster discussion 2: CNS..................................................................................................................................(abs. 734 - 739) Poster discussion 3: Oligometastatic disease.................................................................................................(abs. 740 - 745) Poster discussion 4: Automated planning......................................................................................................(abs. 746 - 751) Poster discussion 5: Optimising and generating CT images ........................................................................(abs. 752 - 757) Poster discussion 6: Normal tissues and Immune-radiobiology..................................................................(abs. 758 - 763) Poster discussion 7: Prostate...........................................................................................................................(abs. 764 - 769) Poster discussion 8: Head and Neck...............................................................................................................(abs. 770 - 775) Poster discussion 9: Image guided protocols.................................................................................................(abs. 776 - 781) Poster discussion 10: The interface of physics and radiobiology.................................................................(abs. 782 - 787) Poster discussion 11: Quality assessment of complex techniques..............................................................(abs. 788 - 793) Poster discussion 12: Patient-centred radiotherapy services.......................................................................(abs. 794 - 799) Poster discussion 13: CNS 2.............................................................................................................................(abs. 800 - 805) Poster discussion 14: Prostate 2......................................................................................................................(abs. 806 - 811) Poster discussion 15: Gynaecological (endometrium, cervix, vagina, vulva)...............................................(abs. 812 - 817) Poster discussion 16: Deep-learning for dose prediction and planning......................................................(abs. 818 - 823) Poster discussion 17: New technologies in image guidance.........................................................................(abs. 824 - 829) Poster discussion 18: Tumour-radiobiology..................................................................................................(abs. 830 - 835) Poster discussion 19: Lower GI (colon, rectum, anus)...................................................................................(abs. 836 - 841) Poster discussion 20: Lung 1............................................................................................................................(abs. 842 - 847) Poster discussion 21: Urology - non prostate................................................................................................(abs. 848 - 853) Poster discussion 22: Managing intra-fraction motion..................................................................................(abs. 854 - 859) Poster discussion 23: MR-guided radiotherapy..............................................................................................(abs. 860 - 865) Poster discussion 24: Radiotherapy planning and quality assurance..........................................................(abs. 866 - 871) Poster discussion 25: Lung 2............................................................................................................................(abs. 872 - 877) Poster discussion 26: Upper GI (oesophagus, stomach) 1............................................................................(abs. 878 - 883) Poster discussion 27: Palliation. ......................................................................................................................(abs. 884 - 889) Poster discussion 28: 4DCT for planning........................................................................................................(abs. 890 - 895) Poster discussion 29: Accuracy in computing dose.......................................................................................(abs. 896 - 901) Poster discussion 30: Challenges and technology of proton-therapy. ........................................................(abs. 902 - 907) Poster discussion 31: Metastatic Prostate......................................................................................................(abs. 908 - 913) Poster discussion 32: Upper GI (pancreas, liver) 2.........................................................................................(abs. 914 - 919) Poster discussion 33: Miscellaneous...............................................................................................................(abs. 920 - 925) Poster discussion 34: Deep-learning for auto-contouring............................................................................(abs. 926 - 931) Poster discussion 35: New delivery techniques.............................................................................................(abs. 932 - 937) Poster discussion 36: Image-guided radiotherapy.........................................................................................(abs. 938 - 943) Clinial track: Digital Posters Head and neck................................................................................................................................................ (abs. 944 - 1028) CNS................................................................................................................................................................. (abs. 1029 - 1073) Haematology................................................................................................................................................. (abs. 1074 - 1082) Breast............................................................................................................................................................. (abs. 1083 - 1147) Lung............................................................................................................................................................... (abs. 1148 - 1204) Upper GI (oesophagus, stomach, pancreas, liver)..................................................................................... (abs. 1205 - 1241) Lower GI (colon, rectum, anus)................................................................................................................... (abs. 1242 - 1277) Gynaecological (endometrium, cervix, vagina, vulva)............................................................................... (abs. 1278 - 1315) Prostate......................................................................................................................................................... (abs. 1316 - 1397) Urology-non-prostate. ................................................................................................................................. (abs. 1398 - 1405) Skin cancer/malignant melanoma.............................................................................................................. (abs. 1406 - 1413) Sarcoma......................................................................................................................................................... (abs. 1414 - 1429) Paediatric tumours....................................................................................................................................... (abs. 1430 - 1438) Palliation........................................................................................................................................................ (abs. 1439 - 1446) Elderly............................................................................................................................................................ (abs. 1447 - 1450) Health services research/health economics.............................................................................................. (abs. 1451 - 1474) Communication............................................................................................................................................ (abs. 1475 - 1481) Other.............................................................................................................................................................. (abs. 1482 - 1533)

DIGITAL POSTERS

Physics track: Digital Posters Adaptive radiotherapy and inter-fraction motion management............................................................. (abs. 1534 - 1575) Basic dosimetry and phantom and detector development..................................................................... (abs. 1576 - 1590) Dose measurement and dose calculation................................................................................................. (abs. 1591 - 1650) Imaging acquisition and processing........................................................................................................... (abs. 1651 - 1695) Implementation of new technology, techniques, clinical protocols or trials (including QA & audit)... (abs. 1696 - 1746) Intra-fraction motion management............................................................................................................ (abs. 1747 - 1775) Quantitative functional and biological imaging......................................................................................... (abs. 1776 - 1779) Radiation protection, secondary tumour induction and low dose.......................................................... (abs. 1780 - 1789) Radiobiological and predictive modelling, and radiomics........................................................................ (abs. 1790 - 1822) Treatment planning: optimisation and algorithms................................................................................... (abs. 1823 - 1856) Treatment planning: applications............................................................................................................... (abs. 1857 - 1910) Radiobiology track: Digital Posters Radiobiology of normal tissues................................................................................................................... (abs. 1911 - 1918) Radiobiology of stem cells (cancer and normal tissue)........................................................................................ (abs. 1919) Radiobiology of particles and heavy ions............................................................................................................... (abs. 1920) Radiation-induced signalling pathways.................................................................................................................. (abs. 1921) Tumour microenvironment......................................................................................................................... (abs. 1922 - 1925) Immuno-radiobiology.............................................................................................................................................. (abs. 1926) Radiation and tumour metabolism............................................................................................................ (abs. 1927 - 1928) DNA damage response................................................................................................................................ (abs. 1929 - 1932) Radiation response biomarkers.................................................................................................................. (abs. 1933 - 1937) RTT track: Digital Posters Patient preparation, positioning and immobilisation............................................................................... (abs. 1938 - 1945) Imaging acquisition and registration, OAR and target definition............................................................ (abs. 1946 - 1952) Treatment planning and dose calculation/QC and QA............................................................................. (abs. 1953 - 1959) Image-guided radiotherapy and verification protocols............................................................................ (abs. 1960 - 1967) Motion management and adaptive strategies.......................................................................................... (abs. 1968 - 1974) Patient care, side effects and communication.......................................................................................... (abs. 1975 - 1986) Education and training/role development................................................................................................. (abs. 1987 - 1990) Risk management/quality management.................................................................................................... (abs. 1991 - 1993)

ABSTRACTS

ESTRO 2021 S1

ESTRO 2021 Abstracts

Saturday 28 August 2021

Teaching lecture: Multidisciplinary research in Europe

SP-0002 Multidisciplinary clinical cancer research: Can we make it better than just the sum of its parts? D. Lacombe 1 1 The European Organisation for Research and Treatment of Cancer (EORTC) , Director General, Brussels, Belgium Abstract Text Cancer clinical research plays a very important part in shaping clinical practice. While traditionally the commercial sector dominates the field of drug development, many questions remain unaddressed in the post marketing space. Optimisation of cancer therapies to define therapeutic strategies is central to establishing standards of care. Questions related to combination, duration, sequence and deescalation typically have been included in the remit of independent researchers. Across disciplines, patient- impactful datasets have been delivered by the non-commercial sector. Independent clinical research programmes attempt to include discipline-specific quality assurance programmes while addressing clinical situations that are not within the remit of the commercial sector. Altogether, these features contribute to the mission and vision needed to deliver patient-centric therapeutic progress. However, not only are multidisciplinary clinical research programmes more challenging than relatively simpler regulatory drug trials, but in addition they are faced with the same regulatory, legal and operational processes in an ever more complex and economically challenging environment. This is further exacerbated in the era of precision oncology, in which early registration of new and expensive anti-cancer agents reach markets with lesser maturity and greater uncertainty, while their cost is a threat to the performance of optimisation trials. High quality multidisciplinary clinical research programmes require central expertise as well as numerous resources at participating sites, adding challenges. Specific protocols address non-drug questions, but radiation oncology or surgery represent the minority of the global research agenda. The reasons are multifactorial and include a lesser degree of awareness and training in methodology both in the academic sector and in the relevant commercial sector, as well as a lack of public investment. Last but not least, as opposed to the drug sector, some technologies and the facilities to receive them must be put in place before they can be tested. As a result of all these reasons, independent investigators often turn to simpler forms of clinical research, such as prospective cohorts or registries. If these approaches do bring some benefits, they also convey a greater uncertainty about the robustness of their conclusions. Because they have to be inclusive of all data to avoid biases as much as possible, they also require an open-minded approach to data sharing, whether using centralised or federated models. Incremental therapeutic progress can be achieved optimally if pre-defined questions are answered using appropriate methodology. “Medical reversal” has been documented for several clinical situations when changing empirically the standards of care. When new methodologies and new solutions for access to data emerge, medical communities should be alerted in order to decide on new standards based on robust methodologies and clinically relevant endpoints. All methodological solutions have their benefits and limits. It is therefore critical that researchers apply them appropriately and reach conclusions taking the limits of the selected methodologies into account. In order to embrace the challenges of the new decade, multidisciplinary partnerships which optimise the expertise and know-how of medical societies and research organisations provide opportunities to prioritise common clinical challenges and conduct appropriate research programmes. Joining forces across disciplines and delivering solid evidence could help our efforts to influence health policy makers to support independent research. Abstract Text The complexity of cancer diagnosis and treatment, with the involvement of several medical specialties, levels of care and hospitals, makes the care organisation relevant in explaining quality of cancer care, both perceived by patients and in terms of clinical outcomes. Multidisciplinary teams (MDTs) working around disease-based tumor boards are the most appropriate way to deal with the clinical decision making, although they are implemented through different ways in the healthcare services. A review of the evidence showed the impact of this approach on improved quality of care and clinical outcomes, even though there are limitations related to the observational nature of most of these studies. Nevertheless, the implementation of MDTs is an ongoing process with different pace and approaches and other endpoints (e.g., care coordination, enrolment to clinical trials) than the clinical ones should be taken into consideration. There are deep changes co-occurring in these times and this could affect how MDTs are conceived and organized. First, the value-based health care would be discussed as an emerging paradigm in cancer care. The contribution of MDTs should consider this framework, which is focused on outcomes as assessed by patients and its associated costs. In this sense, the way patients interact with MDTs could be a relevant point, for instance with the use of PROMs, which together with the information provided by Clinical-Decision Support Systems, modify the exclusive use of medical information by healthcare professionals when making decisions. Networks are another organizational change in the way cancer care is delivered. Whatever way the SP-0003 Multidisciplinary cancer care: Adding value in times of change J.M. Borras 1 , J. Prades 1 1 University of Barcelona, Department of Clinical Sciences, Barcelona, Spain

S2

ESTRO 2021

collaborative networking is formulated, this approach raises some additional questions on radiation oncology due to the concentration of most of the equipment in tertiary hospitals. Radiation oncology should discuss the role they should play in this dynamic environment in which MDTs are increasingly interconnected with the larger health ecosystem (beyond the hospital setting). The need for radiation oncologists to work within the MDTs in a network to coordinate the journey of the patients through different providers and levels of care, or the need to consult expert professionals from other institutions, is a reality to be faced while preserving the involvement of all medical specialties in the therapeutic decision-making process. Finally, a third point to be discussed in the presentation will be the impact of information and communication technologies (ICTs) in MDTs work. COVID pandemic has had as a major consequence the acceleration of ICTs in daily clinical practice (e.g. through teleconsultations) and the use of hypofractionated schemes, which raises the question of how innovations are disseminated and adopted across healthcare services.

Teaching lecture: The microbiome: Its role in cancer development and treatment response

SP-0004 The microbiome: Its role in cancer development and treatment response A.Facciabene USA

Abstract not available

Teaching lecture: Breast reconstruction and radiotherapy

SP-0005 Breast reconstruction and radiotherapy O. Kaidar-Person 1 1 Sheba Medical Center, Oncology, Ramat Gan, Israel

Abstract Text Radiation therapy (RT) is an important treatment modality for non-metastatic breast cancer. Radiation therapy in general, and for breast cancer specifically, evolved significantly over the past years. This follows improvements in technology, imaging, and great efforts of different researchers aiming to improve the therapeutic value of RT, and the quality of life of our patients. Nowadays, the selection of target volumes in case of non-metastatic disease, whether concerning the intact breast (in case of breast conservation surgery) or postmastectomy RT, with or without the regional lymph nodes, depends on individual patient-surgical and disease-related features. In parallel, the surgical techniques for mastectomy and breast reconstruction advanced significantly and often allow for immediate breast reconstruction (IBR). For many years, IBR was not done in cases that were planned for postmastectomy RT. However, due to many reasons, more patients that are now undergoing these procedures are candidates for RT. Therefore, radiation oncologists should aspire to adapt the RT planning volumes and fractionation to reduce the potential toxicity that is associated with RT in the setting of IBR, without compromising oncological outcomes. In the past few years, the ESTRO breast course faculty collaborated with international breast experts, to improve the outcomes of patients who undergo mastectomy and breast reconstruction, resulting in a number of published papers, guidelines and ongoing studies. In this current talk, I will focus on daily clinic work and challenges of treating patients after mastectomy and IBR, present the work done by our team, provide evidence to support our approach and discuss future research that is required in this field.

Teaching lecture: Neurocognitive changes following radiotherapy for primary brain tumours

SP-0006 Evaluation and care of neurocognitive effects after radiotherapy M. Klein The Netherlands

Abstract not available

SP-0007 Imaging biomarkers of dose-induced damage to critical memory regions A. Laprie France

Abstract not available

Teaching lecture: Independent dose calculation and pre-treatment patient specific QA

SP-0008 Independent dose calculation and pre-treatment patient specific QA P- Carrasco de Fez Spain

Abstract not available