To Avert Tamoxifen-Associated Endometrial Polyps, LNG-IUS Could Be the Answer

Oral tamoxifen reduces the likelihood of breast cancer recurrence by acting as an estrogen receptor antagonist in breast tissue; however, tamoxifen also stimulates endometrial cells, which can lead to the development of polyps, hyperplasia, and endometrial cancer. Systemic progestogen, although effective for treating endometrial hyperplasia, has not been shown to ameliorate tamoxifen-induced endometrial effects. During a 1-year trial, investigators assessed the prophylactic efficacy of the levonorgestrel intrauterine system (LNG-IUS) in women receiving tamoxifen. Women were randomized to observation or to LNG-IUS insertion at initiation of tamoxifen therapy. Initial screening included office hysteroscopy with endometrial biopsy and resection of any visible lesions or polyps. The women kept menstrual calendars and reported any pain; all were reassessed at 6 and 12 months by transvaginal ultrasound and hysteroscopy. Biopsy was performed in women with endometrial thickness >8 mm.

Of 145 women eligible for the study, 55 in the LNG-IUS group and 58 in the observation group completed the 12-month assessment. Three women in the treatment group required LNG-IUS removal (1 for pelvic infection and 2 for persistent vaginal bleeding). At 12 months, fewer women in the LNG-IUS group than in the observation group had endometrial polyps (1.8% vs. 15.5%; P=0.02). The LNG-IUS and observation groups had a similar incidence of submucosal fibroids at 12 months (1.8% vs. 3.4%).