A Systematic Review and Meta-Analysis of the Effects of Dietary Isoflavones on Female Hormone-Dependent Cancers for Benefit-Risk Evaluation.

Female hormone-dependent cancers depend on estrogen for their growth. Numerous studies have explored the antitumor effect of dietary isoflavones on female hormone-dependent cancers. Still, few clinical evidence supports the use of isoflavones in female hormone-dependent cancer patients. This study was performed to examine the impact of dietary isoflavones on tumor growth of female hormone-dependent cancers and accelerate the transformation of research from bench to bedside. We searched PubMed Medline, Web of Science, and Google Scholar for relevant articles related to the effect of dietary isoflavone on tumor growth of experimental animal models of female hormone-dependent cancers from 1998 to 2024. The effects of dietary isoflavones on tumor growth were analyzed between the control and treatment groups using comprehensive meta-analysis software (CMA). We included 30 studies describing tumor growth focused on female hormone-dependent cancer types, including breast, ovarian, and uterine cancers. Overall, a pooled analysis revealed that dietary isoflavones reduced tumor volume (Hedge's g = -1.151, 95% CI = -1.717 to -0.585, p = 0.000) and tumor weight (Hedge's g = -2.584, 95% CI = -3.618 to -1.549, p = 0.000). On the other hand, dietary isoflavones increased tumor area (Hedge's g = 1.136, 95% CI = 0.752 to 1.520, p = 0.000). Dietary isoflavones have potential benefits and risks in female hormone-dependent cancers. Therefore, caution should be exercised when considering the intake of dietary isoflavones in female hormone-dependent cancer patients, particularly in the form of supplements.