ESTRO 38 Abstract book

S113 ESTRO 38

recommended for all stage T2 or higher, grade 3, or T1b with LVI. The implant procedure is performed under either local (penile block) or general anesthesia and takes about 30-45 minutes. A minimum of a 2 plane implant is recommended, but up to 3 planes may be required. The median number of needles is 6 (4-12) and ideal spacing between adjacent needles and planes for LDR is 15 mm (range 12-18). Dosimetry can be calculated according to active length and spacing as per the rules of the Paris system for Iridium-192 wire manually after-loaded implants (dose prescribed at 85% of the dose rate minima in the central plane), or calculated from a planning CT scan performed with 1mm slice thickness through the region of interest, The patient is usually hospitalized during the treatment which takes about 5 days at an hourly dose rate of 50-60 cGy per hour. Needles can be removed at the bedside with suitable parenteral analgesia; bleeding is minimal. With increasing availability and popularity of high dose rate brachytherapy, (HDR) and a growing general reluctance regarding manual after loading, HDR is taking a more prominent role in penile brachytherapy, with 4 recent series reporting on over 100 patients. Although the procedures are very similar, in contrast to an LDR implant, needle spacing should be closer in HDR, between 9 and 12 mm. Treatment is fractionated, twice daily with a minimum of 6 hours between. Fraction size is 3-3.5 Gy with a total prescribed dose of 42-51 Gy. Homogeneity parameters are important to minimize complications and it is recommended that the V125% be < 45% and the V150< 20%. Penile preservation is reported at 93-100% at 2 years and 70% at 10 years. Another HDR option involves an individualized or custom mold technique. This is suitable for Tis or minimally invasive T1a tumours. The prescribed dose is 40 Gy in 10 fraction given bid over 5 days. The dose can be prescribed at the required depth (3-5mm). Maximal skin dose should be limited to 120%, with central urethral sparing to receive < 90% of prescription. Two recent small series show promising results. For both methods of brachytherapy,treatment is well tolerated with the acute reaction healing in 2-3 months. As the tumor resolves it will leave a crater which then must re-epithelialize. Cleanliness is maintained with saline soaks, and topical antibiotics, with the addition of Vitamin E as healing progresses.The most common long term complications are soft tissue ulceration in 5-25% (depending on implant volume, dose and tumour stage) which can usually be managed conservatively although hyperbaric oxygen will speed healing in more serious cases, and meatal stenosis requiring either urologic or self-dilatation in 9-45% (depending on proximity of the sources to the meatus). With all the brachytherapy techniques for penile cancer, prolonged follow up is necessary. Although 80% of local failures are within the first 2 years, approximately 20% can occur late, after 5 years. Local recurrences can be managed surgically with no impact on cause specific survival but must be recognized and managed promptly. Patients must be aware of this limitation

Teaching Lecture: Uncertainties in Radiomics

SP-0218 Uncertainties in Radiomics M. Hatt 1 1 Inserm, Laboratory of Medical Infoirmation Processing Latim- Umr 1101, Brest, France Abstract text This lecture will highlight the major uncertainties and methdological pitfalls of radiomics studies. Building on previous experience as well as on a critical review of important published papers, the lecture will detail most important issues associated with image acquisition and pre-processing, object of interest (semi)automatic delineation, features definition, nomenclature and standardization, as well as statistical analysis and machine learning for models training and validation. For each pitfall and issue, the lecture will provide the most up-to- date and currently available methodological solutions, with a focus on options facilitating the transfer of radiomics to the clinical practice. Teaching Lecture: New technology and modalities in Radiotherapy - What can the ESTRO School offer? SP-0219 New technology and modalities in Radiotherapy - What can the ESTRO School offer? J.G. Eriksen 1 1 Aarhus University Hospital, Dept. of Experimental Clinical Oncology, Aarhus, Denmark Abstract text Radiation Oncology is probably one of the most technology-driven medical specialties at all. This is very much reflected by the multidisciplinarity needed for delivering the optimal treatment at the right time and in the right place. MD’s, medical physicists and RTT’s are some of the well-known key persons but also engineers, technicians and IT-professionals play an important role. The development of new technologies in radiotherapy are moving fast forward and it is both a privilege and an obligation of the ESTRO School to keep updated on the educational offers that reflect the technological development. The educational offer should be updated, being able to look into the future and be critical, objective and well balanced. The lecture will discuss why this obligation is so important, the current strategy of the School and give a glimpse of what we can expect in the near future. SP-0220 Precision medicine and systems biology - transforming cancer research in the 21st century W. Kolch 1 1 University College Dublin- Ireland, Systems Biology Ireland and Conway Institute, Dublin, Ireland Abstract text Advances in technologies, especially genome sequencing and other omics methods, are enabling the precise molecular phenotyping of individual cancer patients. Major challenges are now unlocking the information contained in these data and integrating them with each other, but also with clinical data and imaging data. The aim is to obtain a clinically relevant and actionable view of an individual patient’s cancer that allows finer diagnostic stratification, predictions of the course of Teaching Lecture: Precision medicine and systems biology - transforming cancer research in the 21st century

Teaching Lecture: Detector specific output correction factors: How to use them in practice

SP-0217 Detector specific output correction factors: How to use them in practice M.Aspradakis 1 1 Luzerner Kantonsspital Radio-Onkologie, Lusern Swtxzerland

Abstract not received