Introduction/Background Although rare, gynecological cancers following therapeutic radiation are a reality that cannot be ignored nowadays. Ionizing radiation is an established risk factor for the development of primary second cancers While post-radiotherapy gynecological sarcomas are well-documented, it’s harder to prove the existence of post-radiotherapy gynecological carcinomas.

Methodology A retrospective study was conducted at our institution between January 1st, 2018 and December 1st, 2022, to analyze the data of 367 patients hospitalized for the management of a gynecologic cancer. Among these 367 patients, only 9 had a history of gynecologic cancer treated with radiotherapy that met Cahan’s extended criteria for potential radiation induction. These criteria include the location of the second tumor, it’s histology, and the time interval between the initial irradiation and its appearance.

Results The average age at the onset of the first gynecological cancer treated by radiotherapy was 58.6 years and the second post-irradiation cancer was 63.7 years. All nine patients had squamous cell carcinoma of the cervix, all treated with radiochemotherapy. The average dose received was 53.6Gy with fractionation adapted to the stage of each patient, particularly to the different regions to be irradiated. The total duration of radiotherapy varied from 2 to 4 months. 8 of our patients also underwent endovaginal brachytherapy, except for one patient, with an average dose of 26.5 Gy, a fractionation between 6.5 and 7 Gy/F weekly, and a total duration ranging from 2 to 3 months. 8 of our patients developed endometrial cancer after radiotherapy, while the last one presented with ovarian cancer.

Conclusion This topic presents a major challenge: proving that gynecological tumors resulting from previous radiation therapy are radio-induced as there is no histological way to differentiate them from tumors that occur spontaneously. The answer to this question is gradually becoming demystified thanks to the latest developments in molecular biology.

Disclosures All the authors have no financial disclosure or conflicts of interest with the presented material in this presentation.