Evaluation of Ovary Radiation Dose in Breast Cancer Radiotherapy with Modern Techniques: A Prospective Pilot Study

Background: Although the radiotherapy (RT) effect is reversible in some tissues, it is progressive and permanent for the ovary. Ovary radiation exposure during breast cancer radiotherapy (BCR) may cause concern in patients and obstetricians. In this study, we evaluated ovarian radiation doses in patients who received adjuvant radiotherapy for breast cancer prospectively. Methods: Ovary doses were calculated in patients diagnosed with breast cancer (BC) and receiving RT at the Radiation Oncology clinic of Ankara Bilkent City Hospital. Helical intensity modulated radiotherapy (IMRT) planning and three-dimensional (3D) planning were performed for each patient. Results: The data of 8 patients who received BCR at 8 August 2023 and 19 September 2023 were evaluated prospectively. The median age of the patients was 57 (range 39-65), 4 (50%) had breast conserving surgery (BCS), and 4 (50%) patients underwent modified radical mastectomy (MRM). Four (50%) patients were left sided, while four (50%) patients were right sided. According to our results, the ovarian doses in adjuvant radiotherapy of breast cancer patients who received RT with the 3D technique were zero. In helical IMRT plans, the ipsilateral ovary dose was median 12 (range 10-30) centi Gray (cGy); the contralateral ovary dose was median 8 (range 5-13) cGy. In patients with MRM, ipsilateral ovary dose in helical IMRT plans was median 10 (range 10-13); in patients with BCS, it was median 15 (12-30) cGy. Conclusions: This is the first study to examine ovarian doses in breast cancer radiotherapy on patients. In our study, in which we evaluated eight patients with 2 different RT techniques, the dose values of ovaries in breast cancer radiotherapy were found to be negligible and no measurable dose was noted in 3DRT technique.