Effects of ovarian ablation or suppression in premenopausal breast cancer: A meta-analysis of randomized controlled trials

Abstract

Background: The effect of ovarian ablation or suppression (OAS) in premenopausal women with breast cancer is controversial. The overall survival (OS), disease-free survival (DFS) and adverse event of OAS versus no OAS were compared.

Methods: A literature review of EMBASE, Web of Science, PUBMED, and Cochrane Library was conducted. The hazard ratio (HR) and 95% confidence interval (CI) for OS and DFS, as well as risk ratio (RR) and 95% CI for adverse events were evaluated. I-squared statistic (I²) represents heterogeneity.

Results: Twenty-nine studies with a total of 21,249 women were included. In premenopausal women aged 40 years or younger, there were significant differences in OS (HR 0.78, 95% CI: 0.66-0.94, P=0.008, I² = 0%) and DFS (HR 0.84, 95% CI: 0.73-0.97, P=0.02, I² = 0%) between OAS and no OAS. In advanced stage breast cancer, a significant difference was found in OS (HR 0.76, 95% CI: 0.60-0.96, P=0.02, I² = 0%). Patients treated with OAS had more chances to have hot flushes (RR 1.91, 95% CI: 1.62-2.26, P < 0.01, I² = 0%) and vaginal dryness (RR 1.19, 95% CI: 1.08-1.31, P=0.0003, I² = 0%). No significant difference in depression (RR 1.28, 95% CI: 0.94-1.74, P=0.12, I² = 0%).

Conclusions: The study shows that OAS plays a beneficial role in premenopausal women aged 40 years or younger and advanced stage breast cancer. However, OAS is associated with increase in hot flushes and vaginal dryness.

Keywords: Breast cancer; Meta-analysis; Ovarian ablation; Ovarian suppression; Premenopausal.