ESTRO 2024 - Abstract Book

S5383

Radiobiology - Tumour biology

ESTRO 2024

1580

Digital Poster

Uncovering the ovarian cancer radiosensitivity to low and high LET: a preliminary in vitro study

Amelia Barcellini 1,2 , Alexandra Charalampopoulou 3,4 , Gustavo Baldassarre 5 , Giuseppe Magro 6 , Laura Deborah Locati 2,7 , Sandro Pignata 8 , Giorgia Mangili 9 , Maura Sonego 5 , Alessandra Dall'Acqua 5 , Giovanni Battista Ivaldi 10 , Chiara Cassani 11,12 , Marco Giuseppe Pullia 3 , Ester Orlandi 1 , Angelica Facoetti 3 1 National Center for Oncological Hadrontherapy (CNAO), Radiation Oncology Unit, Clinical Department, Pavia, Italy. 2 University of Pavia, Department of Internal Medicine and Medical Therapy, Pavia, Italy. 3 National Center for Oncological Hadrontherapy (CNAO), Radiobiology Unit, Research and Development Department, Pavia, Italy. 4 Istituto Universitario di STUDI Superiori (IUSS), Hadron Academy PhD Course, Pavia, Italy. 5 Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, Division of Molecular Oncology, Department of Translational Research, Aviano, Italy. 6 National Center for Oncological Hadrontherapy (CNAO), Medical Physics Unit, Pavia, Italy. 7 Maugeri Clinical Research Institutes IRCCS, Translational Oncology Unit, Pavia, Italy. 8 Istituto Nazionale Tumori, IRCCS-Fondazione G. Pascale Napoli, Department of Urology and Gynecology, Naples, Italy. 9 IRCCS San Raffaele Scientific Institute, Unit of Gynaecology and Obstetrics, Milan, Italy. 10 Maugeri Clinical Research Institutes IRCCS, Radiation Oncology Department, Pavia, Italy. 11 University of Pavia, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, Pavia, Italy. 12 IRCCS, Foundation IRCCS Polyclinic San Matteo, Unit of Obstetrics and Gynecology, Pavia, Italy

Purpose/Objective:

In recent years, radiotherapy (RT) has been increasingly considered a definitive treatment in oligometastastic ovarian cancers that can be integrated into a multidisciplinary strategy to increase the chemotherapy-free interval. Carbon ion radiotherapy (CIRT) has proved to be effective in several radio and chemoresistant histologies, both in pre-clinical and clinical trials. This enhanced effect might be justified by the higher relative biological effectiveness (RBE) of Carbon ions compared to photons (XRT). However, little is known about the radiobiological effects of irradiation on ovarian cell lines and in particular whether the LET of radiation might influence the response according to the tumour's mutational status. We evaluated the response to low and high LET in three human cell lines of ovarian carcinoma to answer this question.

Material/Methods:

Exponentially growing human OVSAHO (serous papillary adenocarcinoma with BRCA2 and p53 mutation), OVCAR8 (high-grade serous carcinoma with BRCA1 methylation and p53, KRAS and ERBB2 mutation) and OVCAR3 (BRCA wild type and p53 mutated high-grade serous adenocarcinoma) cells cultured in T25-T75 flasks (Falcon and Corning, respectively) were exposed to different treatment schedules (0 Gy, 0.5 Gy, 1 Gy, 2 Gy, 3 Gy, 4 Gy and 5 Gy at physical doses) of XRT or CIRT at room temperature. Sham-irradiated samples (0 Gy) were handled the same way as the irradiated ones but placed in a nearby room. For each cell line data were obtained by three independent experiments, each run in triplicates. The cells’ response to the high and low LET were evaluated using the clonogenic survival assay and survival data fitted by the linear quadratic (LQ) model. Unpaired Student’s t-test with a 2-tailed was used to analyze the potential differences between each treatment among different groups. P value < 0.05 was considered statistically significant.