BACKGROUND AND PURPOSE:

• Association between tamoxifen (a SERM) and endometrial cancer is well known
• The relationship between tamoxifen use and cancer specifically in women who present with polyps is still unclear
• Yela et al. (Menopause, 2019) investigated whether tamoxifen is a cancer risk factor in women with confirmed endometrial polyps

METHODS:

• Retrospective cohort study
• Participants
  • Women undergoing endometrial polypectomy (via hysteroscopy)
• Polyps visualized and confirmed on histology
• Groups
  • Tamoxifen use
  • No tamoxifen use
• Data analysis
  • Univariate and multivariate regression analyses
  • Variables assessed aside from tamoxifen use: Duration of tamoxifen use | Age | BMI | Vaginal bleeding | Menopausal status | Parity | BP | Diabetes mellitus | Polyp size | Smoking status | Hormonal therapy | Breast cancer diagnosis
  • Estimation of prevalence ratio (PR) to analyze factors related to endometrial cancer
• Primary outcome
  • Endometrial cancer prevalence

RESULTS:

• 675 participants
  • Tamoxifen use: n=169 | No tamoxifen use: n=506
  • Mean tamoxifen use duration: 2.8 years
• No difference in cancer occurrence between the two groups (P = 0.083)
  • Tamoxifen use: 4.14%
  • No tamoxifen use: 8.1%
• Following multivariate analysis, tamoxifen was still not a risk factor for endometrial cancer vs nonuse (P = 0.101)
  • Endometrial cancer: PR 0.51 (95% CI, 0.23 to 1.14)
• Factors that increased prevalence of malignancy in the no tamoxifen group included
  • Abnormal uterine bleeding: PR 3.9 (95% CI, 2.08 to 7.29; P < 0.001)
  • Age >60 years: PR 2.1 (95% CI, 1.12 to 3.93; P = 0.021)
  • Nulliparous: PR 3.13 (95% CI, 1.55 to 6.35; P = 0.002)
• Factors that increased prevalence of malignancy in the tamoxifen group included
  • Age >60 years: PR 7.85 (95% CI, 1.05 to 58.87; P = 0.006)
  • Nulliparous: PR 8.36 (95% CI, 2.32 to 30.11; P < 0.001)
• Breast cancer was not a risk factor for increased endometrial cancer prevalence

CONCLUSION:

• Tamoxifen does not appear to be an independent risk factor for endometrial cancer in women undergoing hysteroscopic polypectomy  
• In tamoxifen users
  • Age >60 years increased the prevalence of endometrial cancer by almost 8 times and being nulliparous increased the risk by almost 8.4 times
• Authors acknowledge that other studies have found a higher incidence of malignancy in women with polyps who are being treated with tamoxifen
  • Possible explanations: Present study has larger ‘n’ | Average tamoxifen duration in the present cohort was less than 3 years while patients were on tamoxifen for longer duration in other studies

Learn More – Primary Sources:

Tamoxifen use as a malignancy risk factor in postmenopausal women with endometrial polyps

Related ObG Topics:

Tamoxifen Therapy and Uterine Cancer Risk: The Data and Clinical Implications

Endometrial Cancer: The Basics

Breast Cancer Recurrence Risks Following Endocrine Therapy – 20 Years Out

Endometrial Polyps