ESTRO 2020 Abstract Book

S22 ESTRO 2020

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 , I.R. Vogelius 1 , M. Zamani 2 , J. Friborg 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.

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 impact on RT-induced toxicity of these comorbidities. Based on this background, we evaluated in a retrospective observational study the mixed effect of comorbidities and RT delivery on both acute and late GI and GU toxicity in PC. Material and Methods We included 1617 PC patients of which 1027 underwent definitive RT (dRT) and 590 adjuvant RT (aRT). RTOG- EORTC scales were used for toxicity assessment. Parameters evaluated were age, BMI, comorbidities, Charlson Comorbidity Index (CCI), lifestyles and parameters related to the delivery of RT. A univariate and multivariable analysis was assessed with Chi-square test and logistic regression model, Kaplan-Meier method and Cox regression model, for acute and late toxicity, respectively. Results A correlation between greater minimum margin CTV-PTV and lower acute GI toxicity was observed at multivariable model (p< 0.001) for dRT patients. Furthermore, multivariable analysis confirmed that age ≥ 66 years is associated to a higher rate of late GI toxicity both in the whole cohort of patients (HR: 2.70, 95% CI 1.15-6.39, p= 0.022) and in the aRT cohort (HR: 7.98, 95% CI 1.36-46.66, p= 0.021). A higher dose per fraction (> 2.0 Gy) was associated to GI late toxicity< G2 in patients undergoing aRT (HR: 7.13, 95% CI 1.93-23.24, p= 0.003). A higher incidence of late GI toxicity was also observed in patients undergoing aRT, in case of greater CCI score incorrect for age (HR: 0.13, 95% CI 0.02-0.77, p= 0.025). The same relation was observed for patients undergoing dRT, with the diabetes-hypertension-COPD score (HR: 1.67, 95% CI 1.04-2.69, p= 0.033). Furthermore, for dRT patients late GI toxicity was lower using cone-beam CT (HR: 0.10, 95% CI 0.01-0.81, p= 0.031). and was greater in case of acute toxicity ≥ 2 (p= 0.015). GU toxicity was reduced for dRT patients if treated with image guided RT (fiducial markers: HR: 0.03, 95% CI 0.00-0.25, p= 0.001, or cone beam CT: HR: 0.02, 95% CI 0.00-0.23,vp= 0.001) or with RT advanced modulated techniques (HR: 0.33, 95% CI 0.0-0.25, p= 0.018), as well as in case of greater CTV-PTV margin (HR: 0.10, 95% CI 0.02-0.44, p= 0.002). In the overall population a late GU toxicity < 2 was observed in case of delivery of ≥ 72.8 Gy to prostate or prostate bed, while an acute GU toxicity >2 was predictive of late GU toxicity ≥ 2 (HR 2.99, 95%CI 1.22-7.29, p=0.016). Conclusion Our analysis demonstrate that age and comorbidity have a significant impact on RT toxicity for PC, as well as the use of image-guided RT and advanced technique of delivery. On the contrary, significant correlations with lifestyles have not emerged, according to multivariate analysis. PD-0057 Patient-reported outcomes after prostate only vs prostate and pelvic lymph node radiation therapy. M. Parry 1 , J. Nossiter 2 , T. Cowling 1 , A. Sujenthiran 2 , B. Berry 1 , P. Cathcart 3 , N. Clarke 4 , H. Payne 5 , J. Van der Meulen 1 , A. Aggarwal 6 1 London School of Hygiene and Tropical Medicine,

Poster discussion: CL: Prostate 1

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