Topics:
Breast Cancer • Medical Oncology • NCI-CCC Tumor Board Question • UCLA • HR+ • NCI-CCC Breast Tumor Board Question
Are pre-menopausal women on tamoxifen at risk for endometrial cancer?
Pre-menopausal women make progesterone and their menses are typically lighter on tamoxifen because it's a mild endometrial ER stimulant blocking their own estrogen from binding the ER.
Answer from: Medical Oncologist at Academic Institution
Analysis of endometrial cancer rates in the NSABP P1 trial in women under age 50, demonstrated a relative risk of 1.42 (0.55-3.81) for tamoxifen that was not statistically significant. Per 1000 women, the rates were 0.82 for placebo and 1.16 for tamoxifen. (Fisher et al., PMID 16288118)
Sign in or Register to read more
Answer from: Medical Oncologist at Community Practice
The ACOG position is that Tamoxifen does not increase the risk of uterine cancer in premenopausal women:
https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2014/06/tamoxifen-and-uterine-cancer
Answer from: Medical Oncologist at Academic Institution
Five-year therapy with tamoxifen is associated with a 1-2% risk of endometrial cancer.