Ovarian cyst formation in patients using tamoxifen for breast cancer.

Objective: The purpose of this study was to evaluate patient-related parameters that determine ovarian cyst formation in women using tamoxifen for breast cancer.

Methods: A retrospective review of tamoxifen-treated women with breast cancer who were followed up in the outpatient clinic at Ankara Oncology Hospital between January 2002 and December 2004 was performed. Tamoxifen doses and duration, post-treatment menstrual function, adjuvant therapy, ultrasonographic and hormonal [follicle-stimulating hormone and serum estradiol (E(2))] data, details of gynecologic surgical procedure and histopathology were recorded.

Results: Twenty-nine of 150 tamoxifen-treated patients (19.3%) had ovarian cysts. Cysts were detected in 28 of 57 pre-menopausal women (49.1%) and 1 of 93 post-menopausal women (1.1%). Patients with ovarian cysts had higher serum E(2) levels compared with patients without cysts (24 versus 345 pg/ml; P < 0.001). Patients with ovarian cysts had <1 year amenorrhoea duration (P < 0.001) compared with the patients without cysts. Adjuvant standard chemotherapy did not have relationship between the development of ovarian cysts. Multivariant analysis showed that cyst development is related to high E(2) levels (P < 0.05).

Conclusions: Patients still having a menstrual cycle during tamoxifen had high risk (58.33%) of developing ovarian cysts. We have described an association between pre-menopausal patients using tamoxifen with high E(2) level and ovarian cyst enlargement.