ESTRO 2024 - Abstract Book

S2515

Clinical - Urology

ESTRO 2024

Vittorio L Vavassori 13 , Alessandro Magli 14 , Alice Pastorino 15 , Nicola De Rosa 16 , Nadia G Di Muzio 17,18 , Claudio Fiorino 2 , Cesare Cozzarini 17 1 Ospedale Regionale Parini- AUSL Valle d’Aosta, SSD Radioterapia Oncologica, Aosta, Italy. 2 IRCCS San Raffaele Scientific Institute, Medical Physics, Milano, Italy. 3 IRCCS Istituto Nazionale dei Tumori "Regina Elena", Department of Radiotherapy, Roma, Italy. 4 Comprensorio Sanitario di Bolzano, Radiotherapy, Bolzano, Italy. 5 IRCCS Crob, Laboratory of Clinical Research and Advanced Diagnostics, Rionero in Vulture, Italy. 6 IRCCS Crob, Radiotherapy, Rionero in Vulture, Italy. 7 ASL TO4 Ospedale di Ivrea, Radiotherapy, Ivrea, Italy. 8 Fondazione IRCCS Istituto Nazionale dei Tumori, Department of Radiation Oncology 1, Milano, Italy. 9 Istituto di Candiolo - Fondazione del Piemonte per l'Oncologia IRCCS, Radiotherapy, Candiolo, Italy. 10 Fondazione IRCCS Istituto Nazionale dei Tumori, Unit of Data Science, Milano, Italy. 11 Fondazione IRCCS Istituto Nazionale dei Tumori, Department of Epidemiology and Data Science, Milano, Italy. 12 Ospedale degli Infermi, Department of Radiotherapy, Biella, Italy. 13 Cliniche Gavazzeni-Humanitas, Radiotherapy Unit, Bergamo, Italy. 14 Azienda Ospedaliero Universitaria S. Maria della Misericordia, Department of Radiotherapy, Udine, Italy. 15 A.O. SS. Antonio e Biagio e Cesare Arrigo, SC Radioterapia, Alessandria, Italy. 16 Centro AKTIS Diagnostica e Terapia s.p.a., Radiotherapy, Napoli, Italy. 17 IRCCS San Raffaele Scientific Institute, Department of Radiation Oncology, Milano, Italy. 18 Vita-Salute San Raffaele University, Medicine and Surgery, Milano, Italy

Purpose/Objective:

To report the persistence over time and the severity of radiation-induced hematologic toxicity (HT) after whole pelvis radiotherapy (WPRT) in a large cohort of men with clinically localized prostate cancer (PCa) who underwent intensity modulated radiation therapy (IMRT) with different intents (radical, adjuvant and salvage).

Material/Methods:

IHU WPRT-TOX is a prospective multi-institute cohort study activated in September 2012 at San Raffaele Scientific Institute, Milan, and currently ongoing in 14 Italian Institutes (ClinicalTrial.gov registered study) whose objective is to set up predictive models of radiation-induced intestinal, hematological and urinary toxicity in men receiving WPRT as part of their radiation treatment for PCa. Overall, 887 patients were enrolled up to December 2021 (end of enrollment). According to the study requirements, complete blood tests must be obtained at baseline, at RT mid-point and end, 3 and 6 months after radiotherapy conclusions, and thereafter every 6 months up to 5 years in order to monitor the absolute counts of white blood cells (WBC), neutrophils (ANC), lymphocytes (ALC), platelets (PLT), red blood cells (RBC) as well as the circulating levels of hemoglobin (Hb).

HT was graded according to CTCAE v4.03.

Wilcoxon signed-rank tests were carried out to check each blood count component for differences in absolute value between the baseline and every following time of interest up to 5 years.

Special focus was placed on the trend over time of absolute lymphocyte count stratified by acute G3+ lymphopenia (ALC<500/μL at nadir), to assess any possible role of its reduction at nadir on its dynamics at later stages. Mann Whitney tests for unpaired data were performed between the two groups identified by the endpoint at baseline, acute time and each follow-up time.