ESTRO 36 Abstract Book

S249 ESTRO 36 _______________________________________________________________________________________________

international practice, allowing for further similar studies to be performed in other countries. Material and Methods An evidence-based event reporting-and-learning process map was developed from recommendations in the literature [see Figure 1], followed by a questionnaire to assess a radiation therapy centre’s compliance with this map. Radiation Therapy Service Managers of Irish radiation therapy centres (n=12) were invited to participate in the anonymous online questionnaire. Frequency analysis of closed-ended questions and thematic analysis of open- ended questions was performed to assess the data.

therapy across the globe. With such developments, a worldwide enhancement of the safety-culture in the field of radiation therapy can occur.

Symposium: Non-rectal GI tumours: key open questions to be answered from (and for) the radiation oncologist!

SP-0469 Radio(chemo)therapy in oesophageal cancer: can we do better? M. Hulshof 1 1 Academic Medical Center, Dept Radiation Oncology, Amsterdam, The Netherlands The indications for radiation in esophageal cancer have increased dramatically in the last 15 years, and the developments of chemoradiation for esophageal cancer can be defined as a success story: Preoperative chemoradiation became standard since phase III trials have shown that overall survival did increase in resectable stage of disease and the results from studies with definitive chemoradiation for irresectable\inoperable case has changed the treatment intent from palliative to curative. The indications for palliative radiotherapy remained unchanged. Thus the vast majority of esophageal cancer patients will get radiotherapy somewhere in their disease tract. This recent change is the reason that improvements in radiation accuracy for esophageal tumors are running behind compared to longer existing indications like prostate. Improving radiation accuracy in esophageal tumors is challenging because of its mobility by breathing effects, the anatomical changes that can occur during the treatment period and the difficulties of accurate delineation of macroscopical tumor borders on a CT scan. This challenge becomes even larger because the impact of all these uncertainties have shown to differ between the different levels of the esophagus, i.e. proximal, mid versus distal. Use of fiducials, 4 D imaging, cone beam verification, non- uniformal margins, IMRT and adaptive radiotherapy are tools to improve accuracy and to decrease dose to healthy surrounding tissue, but are not yet routinely applied in most institutes. Still, improving radiation accuracy will probably not have a large impact on tumor control and survival. In contrast to the preoperative treatment, in which dose schedules are well defined and locoregional control is good after surgery, locoregional control in definitive chemoradiation is still disappointing and warrants improvements. Prospective studies are needed and currently running to analyze the effect of dose escalation in definitive chemoradiation. If dose escalation is effective, treatment techniques to adequately deliver the boost dose will become more important (4 D CT scans, fiducials, and CBCT verification). The sensitizing effect of chemotherapy during radiotherapy is well established, but addition of new targeted drugs are expected to increase the treatment response during chemoradiation. The first studies on combining monoclonal antibodies with CRT have been executed with so far somewhat disappointing results. But new drugs are in development and studies on combinations with immune therapeutic agents like PD-L1 inhibition are being conducted. So yes, we can do better, both in terms of accurate dose delivery and improving tumor response. Efforts by radiation oncologists are necessary to provide that the success story of chemoradiation in esophageal cancer has not ended yet. SP-0470 Does radiotherapy still have a role in the management of pancreatic cancer? E. Fokas 1 1 Goethe University Frankfurt, Department of Radiotherapy and Oncology, Frankfurt, Germany

Results A 91.7% response rate was achieved. The following improvements were found to be most in need of occurring: decreased variation in event classification and taxonomy, expanded use of external reporting systems, and heightened dissemination of lessons-learned to wide audiences. A recommendations table was developed to present methods in which required standardisation and enhancement of practice can be achieved [see Table 1].

Conclusion This study identified aspects of Irish event reporting-and- learning systems wherein improvements are necessary. The recommendations made can be utilised to optimise the national standard of incident and near-miss management in Ireland. Due to their evidence-based nature, they can also be applied to the field of radiation