ESTRO 2020 Abstract Book

S23 ESTRO 2020

Department of Health Services Research and Policy, London, United Kingdom ; 2 The Royal College of Surgeons of England, Clinical Effectiveness Unit, London, United Kingdom ; 3 Guy’s and St Thomas’ NHS Foundation Trust, Department of Urology, London, United Kingdom ; 4 The Christie and Salford Royal NHS Foundation Trusts, Department of Urology, Salford, United Kingdom ; 5 University College London Hospitals, Department of Oncology, London, United Kingdom ; 6 King’s College London, Department of Cancer Epidemiology- Population- and Global Health, London, United Kingdom Purpose or Objective Little is known about the toxicity of pelvic lymph node (PLN) irradiation following intensity-modulated radiation therapy (IMRT) for the treatment of men with high-risk prostate cancer. We aimed to compare patient-reported outcomes of IMRT to the prostate and the pelvic lymph nodes (PPLN-IMRT) compared to prostate only IMRT (PO- IMRT). Material and Methods Patients diagnosed with high-risk or locally advanced prostate cancer in the English National Health Service, between April 2014 and September 2016, and treated with IMRT were identified from the National Prostate Cancer Audit. Men were mailed a questionnaire 18 months after diagnosis. Patient-reported sexual, urinary, bowel and hormonal function domains using the EPIC-26, and generic health-related quality of life (HRQoL) using EQ-5D-5L, were collected from patient surveys. Comparator groups (PPLN-IMRT versus PO-IMRT) were compared using linear regression, adjusting for baseline patient, tumour and treatment characteristics. Results Of the 5468 men (78%) who responded to the patient survey, 4196 (77%) received PO-IMRT and 1272 (23%) received PPLN-IMRT. Adjusted mean scores for urinary, bowel, and hormonal EPIC-26 domains, and HRQoL were similar irrespective of the treatment region. Patients receiving PPLN-IMRT reported worse sexual function than those receiving PO-IMRT (-2.26 adjusted mean difference on a 0-100 scale; 95% CI: -3.66 to -0.86, P =0.002) but this was not a clinically meaningful difference. Conclusion PPLN-IMRT is not associated with clinically important differences in patient-reported toxicity for men with high- risk or locally advanced prostate cancer. Results from ongoing trials will provide further insight into the anti- cancer effectiveness of PLN irradiation. PD-0058 Duration of Androgen Deprivation Therapy based on Nadir PSA in High Risk Localized Prostate Cancer Z. Ayoub 1 , J. Khader 2 , M. Bulbul 3 , R. Khauli 3 , T. Andraos 1 , A. Shamseddine 4 , D. Mukherji 4 , F. Geara 1 1 American University of Beirut Medical Center, Radiation Oncology, Beirut, Lebanon ; 2 King Hussein Cancer Center, Radiation Oncology, Amman, Jordan ; 3 American University of Beirut Medical Center, Division of Urology, Beirut, Lebanon ; 4 American University of Beirut Medical Center, Division of Medical Oncology, Beirut, Lebanon Purpose or Objective We have previously shown that a nadir PSA (nPSA) of 0.06 ng/mL is a strong independent predictor of biochemical recurrence-free survival (bRFS) in patients with intermediate or high risk (HR) prostate cancer treated with definitive external beam radiation therapy (RT) and androgen deprivation therapy (ADT). We aimed to examine the association between the duration of ADT and bRFS in HR localized prostate cancer patients, based on nPSA. Material and Methods Between 1995 and 2015, 375 patients with intermediate and HR localized prostate cancer who received definitive RT and ADT were identified. A total of 235 patients had HR

prostate cancer, of whom 204 patients had available data on their posttreatment nPSA and consisted our study cohort. Duration of ADT varied among patients depending on physician preference, patient tolerance, and/or compliance. A total of 157 patients (77.0%) reached the desired nPSA of less than 0.06 ng/mL, while 47 patients (23.0%) had a nadir PSA equal or more than 0.06 ng/ml. Survival outcomes were calculated using Kaplan-Meier methods and compared using the log-rank test. Predictor of outcomes were analyzed using logistic regression. P- value less than 0.05 was considered statistically significant. Results The median age for the entire cohort of 204 patients was 70 years. In patients who reached a nPSA of less than 0.06 ng/mL (favorable group), ADT for at least 12 months lead to superior bRFS compared to ≤ 9 months of ADT (P value 0.036). However, no significant difference in bRFS was seen when examining the value of receiving ADT beyond 12, 15, 18, 21 or 24 months, respectively. On univariate analysis for bRFS, the use of ADT for at least 12 months was significant (HR 0.224; 95% CI 0.070-0.720; P value 0.012) as well as time to nadir PSA tnPSA (≤ 6 vs >6 months); (HR 3.387; 95% CI 1.041-11.023; P value 0.043). The presenting T-stage was borderline significant (HR 3.074; 95% CI 0.972-9.719; P value 0.056), while PSA at presentation, Gleason Score and age were not. On multivariate analysis, the use of ADT for 12 months (HR 0.224; 95% CI 0.070-0.720; P value 0.012) and tnPSA (≤ 6 vs >6 months); (HR 4.369; 95% CI 1.096-17.421; P value 0.037) remained significant. In patients who failed to reach a nPSA target of 0.06 ng/mL (unfavorable group), receiving ADT beyond 9, 12 and 15 months was associated with improved bRFS (P values of 0.044, 0.019, 0.026, respectively). However, beyond 18 months, there was no significant difference. On univariate analysis for bRFS, the only factor that was found to be associated with bRFS was the use of ADT for at least 18 months (HR 0.319; 95% CI 0.110-0.921; P value 0.035). Conclusion In HR localized prostate cancer patients treated with definitive RT and ADT, the total duration of ADT may be adjusted according to treatment response using nPSA. In patients reaching a nPSA below 0.06 ng/mL, a total of 12 months of ADT may be sufficient, while in those not reaching a nPSA below 0.06 ng/mL, a total duration of 18 months is required. PD-0059 Patient-reported baseline incontinence at post-prostatectomy RT: its dependence on time from surgery F. Munoz 1 , G. Sanguineti 2 , P. Gabriele 3 , A. Bresolin 4 , D. Cante 5 , V. Vavassori 6 , J.M. Waskiewicz 7 , G. Girelli 8 , B. Avuzzi 9 , A. Faiella 2 , E. Garibaldi 3 , E. Villa 6 , A. Magli 10 , B.N. Chiorda 9 , M. Gatti 3 , T. Rancati 11 , R. Valdagni 11 , N. Di Muzio 12 , C. Fiorino 13 , C. Cozzarini 12 1 Ospedale Regionale Parini-AUSL Valle d’Aosta, Radiotherapy, Aosta, Italy ; 2 Istituto Nazionale dei Tumori “Regina Elena”, Radiotherapy, Rome, Italy ; 3 Istituto di Candiolo - Fondazione del Piemonte per l'Oncologia IRCCS, Radiotherapy, Turin, Italy ; 4 Fondazione Centro San Raffaele, Department of Medical Physics, Milan, Italy ; 5 Ospedale di Ivrea, Radiotherapy, Ivrea, Italy ; 6 Cliniche Gavazzeni-Humanitas, Radiotherapy, Bergamo, Italy ; 7 Comprensorio Sanitario di Bolzano, Radiotherapy, Bolzano, Italy ; 8 Ospedale degli Infermi, Radiotherapy, Biella, Italy ; 9 Fondazione IRCCS Istituto Nazionale dei Tumori, Radiotherapy, Milan, Italy ; 10 Azienda Ospedaliero Universitaria S. Maria della Misericordia, Radiotherapy, Udine, Italy ; 11 Programma Prostata- Fondazione IRCCS Istituto Nazionale dei Tumori, Radiotherapy, Milan, Italy ; 12 Istituto Scientifico Ospedale San Raffaele, Radiotherapy, Milan, Italy ; 13 Istituto Scientifico