Endometrial cytology and subsequent uterine malignancies in patients treated with long-term tamoxifen for breast cancer

Abstract

Objective: We studied the effect of long-term tamoxifen (TAM) treatment for breast cancer on the endometrium of patients.
Study Design: We analyzed changes in the maturation index (MI), endometrial cytology, and clinicopathological features of subsequent endometrial malignancy.
Result: MI shifted to the right with the dominance of intermediate layer cells. Glandular cells of the endometrium had oval round nuclei with fine granular chromatin in sheets somewhat resembling the secretory phase. Some varied moderately in nuclear or cell size, atrophic change with pyknotic small nuclei, and disordered cell arrangement after 4-5 years of TAM treatment.
Four subsequent cases of uterine corpus cancer were diagnosed after 1-2 year of TAM treatment as endometrioid adenocarcinoma, 2 as adenoacanthoma (all stage Ia and Gl), and 1 as stage IIIc carcinosarcoma. Some previous endometrial cytology showed strongly proliferative findings such as three-dimensional cell groups and tubular structures.
Conclusion: During TAM treatment, early regular cytologic examination of the endometrium is important detecting subsequent uterine corpus malignancy.