Endometrial cancer after tamoxifen-containing adjuvant treatment for breast cancer

Abstract

Background: Breast cancer is the most predominant cancer among women globally, including in Indonesia, and has been recognized as a heterogeneous disease. Hormone-receptor positive breast cancer is the major subtypes of breast cancer which expresses estrogen and/or progesterone receptors and has unique characteristics of favorable prognosis despite predisposes to have a higher risk of late recurrence. Tamoxifen is a selective estrogen receptor modulator (SERM) which has become a drug of choice for adjuvant hormonal therapy to reduce the recurrence risk of hormone-receptor positive breast cancer in pre- or postmenopausal women. Therefore, current clinical guidelines recommend to extend the duration of tamoxifen to increase the benefit of reducing the risk of recurrence. On the other hand, the long-term side effects of tamoxifen are also increasing, including the incidence of tamoxifen-induced endometrial cancer.

Case: This case report presents a clinical case of endometrial cancer emerged in a survivor of hormone-receptor positive breast cancer who previously underwent tamoxifen adjuvant therapy.

Discussion: Eventually, this case report may increase awareness of secondary malignancy and review the incidence, underlying mechanism, risk factors, prevention measures, and current management of tamoxifen-induced endometrial cancer.