ESTRO 2020 Abstract Book

S216 ESTRO 2020

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 radiotherapy after surgery at first treatment: EBRT 15 patients (8.4%), VBT 4 (2.2%), EBRT and VBT 5 (2.8%). EBRT dose range at first treatment was 48.6-50.4 Gy, HDR-VBT dose range was 10-36 Gy. Mean time from diagnosis to recurrence was 30 months. Mean age at the treatment of the recurrence was 68 years (45-87). We staged relapses according to the Perez modification of FIGO classification of primary vaginal carcinoma. 82 relapses (45.9%) were pelvic mass extended to vagina, 95 (53%) were vaginal (50 limited to the dome and 45 with extension to the mid and/or lower third), 2 (1.1%) were centropelvic. Diameter range 1-6.6 cm. 103 recurrences (57.6%) were treated with a combination of pelvic EBRT (mean dose 45 Gy, range 36 - 60 Gy) and HDR-VBT (mean 25 Gy, range 15 - 30 Gy), 48 cases (26.8%) with HDR-VBT alone (mean 40 Gy, range 35 - 45 Gy) and 5 cases (2.8%) with EBRT alone (mean 60 Gy). Five patients (2.8%) were treated with surgery and VBT, 2 patients (1.1%) with CTH and VBT, 10 patients (5.6%) with surgery followed by EBRT and VBT, 2 patients (1.1%) with a combination of all these approaches. Toxicity was scored according to the CTCAE 4.3. Patients characteristics are shown in the Table.

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.