Comparative efficacy and safety of two radiotherapy protocols for ovarian ablation in patients with metastatic breast cancer.

The present study aimed to evaluate the efficacy and safety of radiotherapy (RT) for ovarian ablation (OA) in patients with metastatic breast cancer by comparing two RT protocols: 15 Gy in 5 fractions (arm A) vs. 20 Gy in 10 fractions (arm B). For this purpose, the present study enrolled 68 patients, divided equally into two study arms. The patients were followed-up for 24 weeks post-intervention. The primary endpoint was the efficacy of RT in inducing OA, assessed through amenorrhea and hormone levels [follicle-stimulating hormone (FSH) and estradiol]. Toxicities were evaluated using the Common Toxicity Criteria for Adverse Events version 5.0, and post-menopausal symptoms were assessed using the Menopause Rating Scale. The results revealed that there was no significant difference between the two study arms (A vs. B) in the rate of amenorrhea development and persistence (85.7 vs. 89.5%), and in the achievement of postmenopausal estradiol (91.2 vs. 94.1%) and FSH levels (79.4 vs. 88.2%). Both regimens led to a significant reduction in estradiol levels and an increase in FSH levels compared to baseline levels. No grade ≥3 toxicity was observed. Common postmenopausal symptoms included hot flushes and irritability, with no significant differences between the groups. On the whole, the present study demonstrates that both RT regimens are effective and safe for OA in patients with metastatic breast cancer, with no significant differences in efficacy or toxicity. The findings are particularly relevant in resource-limited settings, underscoring the potential for flexible and shorter treatment regimens in such environment.