Purpose: To assess the long-term natural history of simple ovarian cysts diagnosed in postmenopausal patients with breast carcinoma treated with tamoxifen citrate.
Materials and methods: Of 332 postmenopausal women with breast cancer who were treated with tamoxifen, 32 (9.6%) had simple ovarian cysts. Long-term follow-up transvaginal ultrasonography (US) was performed in patients who had these simple ovarian cysts, and serum CA 125 samples were taken. Standard linear regression analysis with repeated measurements with irregular time points with the mixed-effects model was used to correlate cyst size at transvaginal US with the time elapsed since the diagnosis of ovarian cysts. Statistical analysis was performed by using the t test for regression slope.
Results: There was a significant decrease in cyst size over time (P =.017). Three (9%) of the 32 patients underwent surgery. Histologic evaluation of the removed ovaries revealed simple ovarian cyst, well-differentiated ovarian carcinoma, and metastatic adenocarcinoma. The remaining 29 (91%) continued with regular follow-up examinations only. In 11 (34%) of the 32 patients there were no changes in cyst size over time. In nine patients (28%) additional cysts appeared. Cysts disappeared, increased in size, disappeared and reappeared, or decreased in size in four (12%) patients each. Serum CA 125 levels were within the normal range.
Conclusion: In postmenopausal patients with breast carcinoma who were treated with tamoxifen, long-term follow-up US of simple ovarian cysts demonstrates a significant decrease in cyst size over time.