Abstract
BACKGROUND: The selective estrogen receptor modulator tamoxifen is now widely used for the treatment and prevention of breast cancer. Tamoxifen use has been associated with a variety of gynecologic problems. Despite the frequency with which hormonal therapy is used for the treatment of breast cancer, limited population-level data are available to describe the occurrence of gynecologic conditions and the use of surveillance testing in women receiving tamoxifen and aromatase inhibitors. OBJECTIVE: We performed a population-based analysis among women with breast cancer receiving hormonal therapy with tamoxifen, a drug commonly used in premenopausal and sometimes postmenopausal women, to determine the frequency of gynecologic abnormalities and use of diagnostic and surveillance testing. We compared these findings to women treated with aromatase inhibitors, agents commonly used in postmenopausal women. STUDY DESIGN: The MarketScan database was used to identify women diagnosed with breast cancer from 2009 through 2013 who underwent mastectomy or lumpectomy. Women receiving tamoxifen (age <50 vs ≥50 years) were compared to women ≥50 years of age treated with aromatase inhibitors. We examined the occurrence of gynecologic symptoms and diseases (vaginal bleeding, endometrial polyps, endometrial hyperplasia, and endometrial cancer) and gynecologic procedures and interventions (transvaginal ultrasound, endometrial biopsy, hysteroscopy/dilation and curettage, and hysterectomy). Time-dependent analyses were performed to examine symptoms and testing. RESULTS: A total of 75,170 women, including 15,735 (20.9%) age <50 years treated with tamoxifen, 13,827 (18.4%) age ≥50 years treated with tamoxifen, and 45,608 (60.7%) age ≥50 years treated with aromatase inhibitors were identified. The cumulative incidence of any gynecologic symptom or pathologic diagnosis during the study period was 20.2%, 12.3%, and 3.5%, respectively (P < .001), while the cumulative incidence of any gynecologic procedure or intervention during the study period was 34.2%, 20.9%, and 9.0%, respectively (P < .0001). Among women without symptoms or pathology, interventions were performed in 20.0%, 11.0%, and 6.8%, respectively (P < .0001). CONCLUSION: Compared to women taking aromatase inhibitors, gynecologic symptoms, procedures, and pathology are higher for both premenopausal and postmenopausal women with breast cancer on tamoxifen. Increased efforts to curb use of gynecologic interventions in asymptomatic women are needed.