Abstract P4-14-13: Tamoxifen induced ovarian hyperstimulation during hormonal therapy for breast cancer

Abstract

Abstract Introduction Adjuvant endocrine therapy is an integral compo-nent of care for endocrine-dependent breast cancer. To date, international consensus statements recommend tamoxifen (20 mg/day) for five years as the standard adjuvant endocrine therapy for premenopausal women. Tamoxifen is a potent inducer of ovarian function and consequent hyper-estrogenism in premenopausal women. However, the incidence rate and risk factors associated this phenomenone were not clarified. Methods Among consecutive patients who were operated under diagnosis of breast cancer from March 2012 to December 2016 in Chung-Ang university hospital, patients who received post-operative tamoxifen therapy for endocrine-dependent breast cancer (stage 0-III) at age under 60 were selected and retrospectively analysed. Serial data on serum estradiol and follicular stimulating hormone(FSH) were collected. When the serum concentration of estradiol was higher than 400 pg/mL, which exceeds the normal estradiol production by a single preovulatory follicle, we classified them as tamoxifen induced ovarian hyperstimulation group. Clinicopathologic factors were analyzed between ovarian hyperstimulation group and non-hyperstimulation group by x2 and student t-test. Results Among 205 patients, 19 patients(9.3%) showed high values of serum estradiol during tamoxifen therapy. They showed 44 times of high estradiol level during follow up period. The serum concentrations of estradiol and FSH were 1047.97638.8pg/mL and 11.57.3 mIu/mL, respectively. The mean duration from the start of the single administration of tamoxifen to the initial detection of a high concentration of estradiol was 666.4+433.1 days. Univariate and multivariate analysis between ovarian hyperstimulation and non-hyperstimulation groups showed younger age(<40years) and only endocrine therapy without chemotherapy were related to higher prevalence of ovarian hyperstimulation significantly. (p <0.001, =0.031 each) Pathologic stages and progesterone receptor expressions on breast tumor were not related to manifestation of ovarian hyperstimulation. Conclusions The Incidence rate and occurrence time of ovarian hyperstimulation associated with adjuvant tamoxifen treatment in breast cancer patients under age 60 were 9.3% and around 2-year after treatment with tamoxifen. Young age under 40 years old and endocrine treatment without chemotherapy were risk factors predicting occurrence of ovarian hyperstimulation during tamoxifen treatment. It should be noted that tamoxifen is a potent inducer of ovarian function and close monitoring of the endocrine parameters during treatment with tamoxifen would be essential. Citation Format: Kim MK, Shin H-c. Tamoxifen induced ovarian hyperstimulation during hormonal therapy for breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-13.