Abstract Book

S115

ESTRO 37

dose to critical structure for a limited number of fractions. Thus, the current clinical focus is on mitigating potential impacts of proton RBE uncertainties. This presentation will summarize our current knowledge of RBE variations as a function of normal tissue and tumor endpoints, as a function of dose, and as a function of energy deposition characteristics. Uncertainties with respect to in vivo RBE predictions will be discussed and implications in treatment planning for passive scattering and proton beam scanning will be outlined. Further, the current clinical evidence supporting a change in current clinical practice will be reviewed. Moving forward, one potential strategy is to focus on the well-known fact that the RBE is increasing with increasing LET. One can improve a treatment plan by redistributing the LET away from critical structures without signi- ficantly changing the dose distribution. SP-0210 Pre-clinical cancer models R.F. Jackstadt 1 1 Beatson Cancer Centre, Colorectal Cancer and Wnt Signalling, By Biggar, United Kingdom Abstract text Pre-clinical cancer models are a crucial tool to understand cancer biology and to find treatment strategies that will show maximized efficiency in early clinical phases. Particularly, with recent research identifying the importance of the tumour microenvironment and the potential for immunotherapy in cancer treatment, autochthonous immunocompetent models will depict an important part of pre-clinical studies in the future. Nevertheless, these models are time and cost intensive, underlining the need of models which faithfully resemble the human disease. The current state of mouse models used in pre-clinical cancer drug testing such as patient derived xenografts (PDXs) and genetically engineered mouse models (GEMMs) will be discussed, as well as assets and drawbacks of these models. Particularly, aspects of pre-clinical mouse models which lead to sub-optimal translation of therapies into the clinics will be addressed. As an example, of improved pre-clinical strategy, the stratification of colorectal cancer GEMMs primary tumours by comprehensive transcriptional profiling and cross comparison to human datasets will be highlighted. Furthermore, it will be discussed how this stratification helps to find effective tailored therapies in newly developed models which more accurately resemble the human disease. SP-0211 Supportive care in head and neck cancer patients: self-management and eHealth I. Verdonck-de Leeuw 1 1 VU University Medical Center, Otolaryngology / Head and Neck Surgery, Amsterdam, The Netherlands Abstract text A major challenge in treating head and neck cancer is to obtain a high cure rate while preserving vital structures and function, preventing treatment related-symptoms, and maintaining good health related quality of life (HRQOL). The main aim of supportive care is to improve HRQOL. In many countries, government policy Teaching Lecture: Pre-clinical cancer models Teaching Lecture: Supportive care in head and neck radiotherapy

statements and national guidelines reflect broad scientific and societal support for an integrated approach to supportive care in cancer patients, including rehabilitation, psychosocial care, and lifestyle interventions. Using patient reported outcome measures (PROMs) in clinical practice is recommended to monitor HRQOL and to facilitate adequate referral to supportive care. Currently, much effort is undertaken to use the concept of value based health care to optimize (head and neck cancer) care, which can be translated into three components: tailoring of care to the needs of the individual patient (patient-centered care), offering effective care (quality care), and offering cost-effective care (affordable care). An important aspect in this type of care is patient’s self-management. There are six core self-management skills: problem solving, decision making, resource utilization, forming of a patient/health care provider partnership, taking action, and self- tailoring. E-health applications including PROMs to monitor HRQOL, computerized decision support, and self- help interventions facilitate supportive care. However, the diversity and unconnectedness of available supportive care options (online and face-to-face) remains a problem and many cancer patients have unmet needs. This presentation provides an overview of evidence of (cost)effectiveness of supportive care with a special focus on self-management and eHealth. Abstract text Anal squamous cell carcinomas (ASCC) are increasing in frequency across the developed world, and 70-90% of all cases originate from infection with human papilloma viruses (HPV). Primary chemoradiotherapy (CRT) with 5- fluorouracil and mitomycin C remains the standard treatment for ASCC, but local and/or distant failure still occurs in up to 30% of patients. In the present lecture, the epidemiology and pathophysiology of ASCC in the context of HPV will be discussed. The evidence from randomized clinical trials, and the definitions of clinical primary and secondary endpoints will be presented. Although largely effective, especially in early-stage tumors, CRT is associated with significant late side effects. The latter underlines the importance of using modern radiotherapy techniques such as intensity- modulated radiotherapy (IMRT) and image-guided radiotherapy (IGRT) to facilitate highly conformal plans, but the need to possibly consider reduction of tumor volume margins and/or the radiation dose to organs at risk. Furthermore, although promising, early-phase trials using targeted agents such as cetuximab in combination with CRT failed to improve the clinical outcome, whereas higher toxicity was observed in ASCC patients. Hence, there is an unmet need to develop develop accurate predictive biomarkers to guide therapeutic decisions. Finally, novel approaches, including immunotherapy, and new clinical trials, also with RT dose stratification according to clinical stage will be summarized. Teaching Lecture: Anal cancer: Can we individualise treatment? SP-0212 Anal cancer: Can we individualise treatment? E. Fokas 1 1 Klinikum der Johann Wolfgang Goethe Univ, Department of Radiotherapy and Oncology, Frankfurt, Germany