ESTRO 36 Abstract Book

S152 ESTRO 36 _______________________________________________________________________________________________

there is still some room for serendipity: an example of this will presented with flash-RT.

prognosis significantly superior than HPV negative tumor.Although their survival is excellent, standard RT-CT regimens produce substantial toxicity.In that scenario strategies for de-intensification have been developed.De- intensification is to modify the standard treatment in order to reduce the long-termtoxicities associated with radiation / chemotherapy while maintaining the high cure rates.Prognostic factors allow us to select patients with excellent outcomes that can benefits from de- intensification strategies. This factors are: Oropharyngeal cancer, P16 +, minimalsmoking history, non bulky primary and non-extensive nodal spread (not N2c-N3).Strategies for de-intensification are: Select chemo responders and reduce RT dose or thevolume, reduce RT dose and cisplatin, replace cisplatin with cetuximab, use TORSresection and reduce adjuvant RT dosePublished de- escalation clinical trial will be presented and discussed as well as the mostimportant ongoing trials.As conclusions: radiation de-escalation is experimental and should be conducted in clinicaltrials, appropriate candidates for de- escalation are well defined, there are differentstrategies for de-intensification, preliminary data show efficacy but the effect on long-termtoxicity reduction need to be proved. SP-0294 Health Technology Assessment: what’s in a word? A. Aggarwal 1 1 London School of Hygiene and Tropical Medicine, Health Services Research and Policy, London, United Kingdom Health Technology Assessments (HTA) aim to ensure rational and fair decisions are made on resource allocation for new health interventions. The advantage of HTAs are their universality when making decisions regarding which treatments across all medical specialities represent the best value to society. However, few if any countries internationally use HTA in the evaluation of radiation technologies. Instead these processes have largely focussed on new cancer drugs, informing reimbursement policy for public health systems. In the absence of HTA processes, low regulatory barriers have resulted in the relentless diffusion of increasingly expensive radiotherapy innovations which offer ever- marginal gains in the therapeutic ratio. Without a rational and evidence based approach to evaluation the costs of delivering cancer care will continue to rise exponentially. I will discuss how a commitment to HTA processes is imperative in order to avoid many of the entrenched interests and inefficient practices that have manifest in high income countries due to differences in cancer care delivery, and health system financing. I will also highlight the challenges in establishing HTA for radiotherapy interventions, given the diversity in innovation, and limitations within the evidence base to enable comparative effectiveness research. In addition I will offer insights into the challenges of implementing HTA decisions in practice, using the experiences of the UK National Institute for Health and Clinical Excellence (NICE) as an example. Specifically, the impact of political, public and media pressure on HTA assessments of cancer therapies as well as the negative consequences of bypassing these value driven approaches to reimbursement policy. Symposium with Proffered Papers: Costs and value of radiotherapy innovations: how to assess

Symposium: New paradigm in HNSCC

SP-0291 Modern biomarkers for therapeutic strategy: radiation dose or volume modification M. Krause 1 1 TU Dresden- Med. Faculty Carl Gustav Carus, Dresden, Germany Decisions on radiotherapy indication, dose or combined treatments are today based on tumour stage and localisation as well as surgical factors. Over the last years, an increasing number of translational studies has shown biological parameters that are associated with locoregional tumour recurrences, metastases and/ or patient survival. Most prominent and already in clinical Intervention trials is Human Papillomavirus (HPV) subtype 16, which is present in a high percentage of head and neck squamous cell carcinoma (HNSCC) and has been shown to lead to radiosensitivity of tumours in preclinical as well as in clinical studies. Other biomarkers like hypoxia related markers or putative cancer stem cell markers are expected to indicate a higher radioresistance of tumours. Such biomarkers, after systematic validation in independent datasets, may build a basis for interventional trials with different radiation doses for different risk- stratified patient groups. Less data is currently available on biomarkers predicting the efficacy of radiotherapy to different treatment volumes, e.g. unilateral versus bilateral neck Irradiation or selective inclusion of different lymphnode levels. Such data are harder to generate as they need to base on patient groups that have been treated using different treatment volumes. The talk will give an overview on current clinical evidence, translational studies and promising biomarkers evaluated within clinical Trials. SP-0292 The changing role of head and neck surgeon in HPV-positive oropharyngeal squamous cell carcinoma, or do we still need surgery? C. Simon 1 1 Centre Hospitalier Universitaire Vaudois, Lausanne Vaud, Switzerland HPV-positive oropharyngeal squamous cell carcinomas (OPSCCs) are delineating a separate disease entity with an overall better prognosis and different biology in comparison to HPV-negative OPSCCs. The role of the surgeon for this disease remains to be elucidated and depends on the outcome of surgical trials, i.e the “Best- of” EORTC 1420 trial, that is comparing IMRT with trans- oral surgery in early-stage OPSCCs. Also for advanced- stage disease trials are currently underway to better define adjuvant treatment after surgery (PATHOS, ECOG 3311) or compare surgery-based treatments for operable advanced OPSCCs with RT-strategies (ORATOR). It will depend on the outcome of these trials, which role the surgeon will play in the future in the treatment of HPV- positive OPSCCs. SP-0293 Radiation de-escalation strategies in HPV- positive squamous cell carcinoma J. Giralt 1 1 Hospital Universitario Vall d'Hebron, Barcelona, Spain Human papillomavirus-related (HPV+) oropharyngeal cancer is a rapidly emerging diseasein many countries that differs from tobacco-related and alcohol-related (HPV– )oropharyngeal cancer. HPV+ oropharyngeal carcinoma is now established as a distinctbiological entity, being