ESTRO 2020 Abstract book

S22 ESTRO 2020

1 Rigshospitalet, Department of oncology, Copenhagen, Denmark ; 2 Rigshospitalet, Department of Otorhinolaryngology- Head and Neck Surgery and Audiology, Copenhagen, Denmark Purpose or Objective Isolated regional recurrences following primary radiotherapy for head and neck squamous-cell carcinomas (HNSCC) are often accessible for curatively intended salvage treatment. Factors prognostic for outcome were investigated in a large cohort of HNSCC patients. Material and Methods In total, 1811 patients from Rigshospitalet, Copenhagen receiving curatively intended radiotherapy from 2007 to 2017 were reviewed and recurrences divided into local (T), regional (N) and distant (M). Isolated regional recurrences were identified, and possible salvage surgery was categorized as radical, non-radical, or uncertain radicality based on the description of the surgical margins in the pathology report (free, involved, or uncertain margins). Factors associated with survival and time to second recurrence were investigated using univariate and multivariate analyses. Results Overall treatment failure was recorded in 591/1811 patients (33%). Recurrence in T-site was seen in 356 patients, distant metastases in 186 patients and N-site in 199 patients, whereas 95 patients had an isolated regional recurrence accounting for 5.2% of the whole cohort. Eighty of the 95 patients (84%) received salvage surgery, after which 45/80 (52%) experienced a second recurrence. Two-year survival after isolated regional recurrence was 40%, which was better than in patients with recurrence in T-site only, TN-site only or metastatic disease (p<0.001). Overall survival and time to second recurrence were associated with p16-positive oropharyngeal squamous cell carcinoma (OPSCC) and resection status of the salvage surgery, whereas extracapsular extension had no independent influence. Conclusion Long-term survival after regional recurrence in HNSCC is possible. p16-positive OPSCC and radical salvage surgery are associated with better outcome. PD-0056 Factors predicting acute and late gastrointestinal and genitourinary toxicity in prostate cancer A. Arcelli 1 , F. Deodato 2 , M. Buwenge 1 , M. Ntreta 1 , G. Siepe 1 , E. Ndoci 1 , A. Zamagni 1 , S. Bisello 1 , E. Alexopoulou 3 , G. Macchia 2 , S. Cilla 4 , A.G. Morganti 1 , G.P. Frezza 5 , S. Cammelli 1 1 Radiation Oncology Center- University of Bologna, Department of Experimental- Diagnostic and Specialty Medicine - DIMES, Bologna, Italy ; 2 Radiotherapy Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Campobasso, Italy ; 3 University of Patras Medical School, Department of Radiation Oncology, Patras, Greece ; 4 Medical Physic Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Campobasso, Italy ; 5 Radiotherapy Department, Ospedale Bellaria, Bologna, Italy Purpose or Objective Radiation therapy (RT) is a therapeutic option for prostate cancer (PC). However, RT can result in gastrointestinal (GI) and genitourinary (GU) toxicity worsening patient's quality of life. These side effects depend by delivery of RT as well as by patients’ lifestyle and comorbidities. Hence, literature mainly reports studies evaluating separately the Poster discussion: CL: Prostate 1

Conclusion In pts treated with (CT)RT for HNSCC PROMS at baseline predict for symptomatic response to therapy and long- term pt reported morbidity. Although an initial deterioration in symptoms and QOL immediately after RT is expected, this study shows that those with a moderate or high symptom burden at baseline experience an early and durable benefit to symptoms from (CT)RT. This data can help inform discussion with pts prior to therapy. PD-0055 Outcome in patients with isolated regional recurrence after radiotherapy for head and neck cancer A.M. Lindegaard 1 , C. Von Buchwald 2 , J.H. Rasmussen 2 , L. Specht 1 , R.V. Ivan 1 , M. Zamani 2 , F. Jeppe 1