ESTRO 2020 Abstract book

S234 ESTRO 2020

Kingdom ; 7 Institute of Oncology Ljubljana, Department of Radiotherapy, Ljubljana, Slovenia ; 8 Postgraduate Institute of Medical Education and Research, Department of Radiotherapy and Oncology, Chandigarh, India ; 9 The Radium Hospital- Oslo University Hospital, Department of Oncology, Oslo, Norway ; 10 Cross Cancer Institute and University of Alberta, Department of Oncology, Edmonton, Canada ; 11 Radiotherapiegroep Arnhem, Department of Radiotherapy, Arnhem, The Netherlands ; 12 St James's University Hospital, Leeds Cancer Centre, Leeds, United Kingdom ; 13 UZ Leuven, Department of Radiation Oncology, Leuven, Belgium ; 14 St. Olavs Hospital, Clinic of Oncology and Women's Clinic, Trondheim, Norway ; 15 Amsterdam University Medical Centers- University of Amsterdam, Department of Radiation Oncology, Amsterdam, The Netherlands ; 16 Leiden University Medical Center, Department of Radiation Oncology, Leiden, The Netherlands Purpose or Objective To examine risk factors associated with the occurrence of late diarrhoea in Locally Advanced Cervical Cancer (LACC) patients treated with radio(chemo)therapy and Image- guided adaptive brachytherapy (IGABT). Material and Methods From 2008 to 2015 a total of 1416 patients were enrolled in the prospective observational EMBRACE study (an international study on MRI-guided brachytherapy in LACC). Treatment combined external beam radiotherapy (EBRT) delivered as 45-50Gy in 25-30 fractions ±para-aortic node (PAN) irradiation and IGABT ±chemotherapy. Physician assessed (CTCAE v.3) and patient reported (EORTC) diarrhoea was evaluated at baseline and at regular follow- ups (FUPs). Potential patient- disease- and treatment- related risk factors were tested in univariate (UVA) and multivariable (MVA) analyses (Cox proportional hazards model) for crude incidence of moderate (CTCAE G≥2), severe (CTCAE G≥3) and “very much” (EORTC) diarrhoea (table 1). Binary logistic regression was used for analysis of persistence of diarrhoea, defined as mild and moderate if CTCAE G≥1 and G≥2 were scored in at least half of all FUPs, and analogue if patients reported ”quite a bit or worse” (substantial) diarrhoea in EORTC. EBRT lymph node (LN) irradiation was categorized according to boost/no boost, prescription dose and volume (V57Gy_categorized). As EBRT related parameters such as prescribed dose (elective target), PAN irradiation, total treated body volume to 43Gy (V43Gy) and LN irradiation are correlated (Spearman correlation coefficients r>0.25) each were tested in separate MVAs. Results Patients with CTCAE and EORTC information available (n=1199/1000) were analysed. Median FUP was 48 months (range:1-124) and median age was 49 years (range:21-91). 86% received ≥4 full cycles of cisplatin. Crude incidence of G≥2/G≥3 (CTCAE) diarrhoea were 9.9% (n=119)/1.6% (n=19), respectively. Crude incidence of “very much” (EORTC) diarrhoea was 7.9% (n=79). Mild/moderate (CTCAE) persistent diarrhoea was 16.3% (n=196)/1.7% (n=20), while persistent substantial (EORTC) diarrhoea was 6.5% (n=65). Hazard/Odds Ratios for MVAs are shown in table 1. Statistically significant factors included smoking, diabetes, presence of ≥G1 baseline diarrhoea, large LN boost (V57Gy median≥165cc), PAN irradiation, EBRT prescribed dose, V43Gy, bowel and rectum D2 cm3.

Conclusion Risk factors for late diarrhoea after radio(chemo)therapy and IGABT in LACC reported by patients and assessed by physicians, included: diabetes and presence of baseline diarrhoea (for CTCAE G≥1) associated with increased risk of having persistent diarrhoea; smoking associated with both incidence and persistence of diarrhoea; dosimetric factors from EBRT and brachytherapy (BT) i.e. prescribed dose and size of treated volumes (V43Gy, LN boost, PAN irradiation) associated with incidence and increased risk of persistent diarrhoea. The significance of bowel and rectum D2 cm3 indicates an influence of the high dose from BT to certain areas/sub structures in the occurrence of diarrhoea. PH-0405 Updated mono-institutional analysis of 179 vaginal and pelvic recurrences of endometrial cancer V. Chiofalo 1 , J. Di Muzio 2 , V. Richetto 3 , E. Madon 3 , D. Katsaros 4 , S. Gribaudo 5 1 University of Torino, Oncology- Radiation Oncology, Torino, Italy ; 2 A.O.U. "Città della Salute e della Scienza di Torino", Oncology- Radiation Oncology, Torino, Italy ; 3 A.O.U. "Città della Salute e della Scienza di Torino" P.O. Sant'Anna, Radiation Oncology- Physics, Torino, Italy ; 4 A.O.U. "Città della Salute e della Scienza di Torino" P.O. Sant'Anna, Surgical Sciences- Gynecologic Oncology, Torino, Italy ; 5 A.O.U. "Città della Salute e della Scienza di Torino" P.O. Sant'Anna, Oncology- Radiation Oncology, Torino, Italy Purpose or Objective The aim of the present study is to evaluate clinical endpoints (LC and DFS) and toxicity in the treatment of vaginal and pelvic recurrence of endometrial carcinomas with HDR-VBT alone or combined with EBRT. Material and Methods We retrospectively reviewed a cohort of 179 patients treated for vaginal and pelvic recurrence from endometrial carcinoma between April 1997 and February 2019. 69 patients (38.5%) had FIGO Stage IA, 80 FIGO Stage IB (44.7%), 17 FIGO Stage II (9.5%) and 8 FIGO Stage III (4.5%). Predominant histology was endometrioid adenocarcinoma (136 patients, 76%). Adjuvant