The effectiveness of controlled ovarian stimulation with tamoxifen for patients with estrogen‐sensitive breast cancer: A systematic review and meta‐analysis

PURPOSE: Tamoxifen is used for the suppression of estrogen‐sensitive tumor recurrence in oocyte retrieval cycles. This meta‐analysis aimed to evaluate the quality of controlled ovarian stimulation (COS) with co‐administration of gonadotropins and tamoxifen (COS with tamoxifen). METHODS: PubMed, Embase, and Cochrane Library were searched for articles on October 30, 2022. The authors included studies comparing COS with tamoxifen and COS with gonadotropins and letrozole (COS with letrozole) or gonadotropin only (COS with gonadotropin only) for fertility preservation in patients with breast cancer. The main outcome measures were the COS quality, total number of retrieved oocytes (TOR), total number of mature oocytes (TMO), and peak estradiol levels (PEL). RESULTS: Four studies (348 patients, two randomized controlled trials, and two cohort studies) were included in our meta‐analysis. There was no significant difference in TOR (95% CI, [−3.84, 2.90]) and TMO (95% CI, [−2.20, 2.64]) between COS with tamoxifen and COS with letrozole. There was also no difference in TOR (95% CI, [−6.14, 1.86]) between COS with tamoxifen and COS with gonadotropin only. Statistically significant decrease was observed in PEL during COS with letrozole compared with tamoxifen (95% CI, [1414.4, 4953.7]). CONCLUSIONS: The quality did not differ between COS with tamoxifen and COS with letrozole or gonadotropin only.