[Effects of long-term administration of tamoxifen on vaginal epithelium and complications of endometrial lesions in breast cancer patients].

The effects of tamoxifen (TAM) on 56 postoperative breast cancer patients who were orally administered TAM and followed up at Cancer Institute Hospital from 1989 to 1992 were studied retrospectively. The maturation index (MI) and karyopyknotic index (KPI) were employed to investigate the effects of TAM on vaginal epithelial cells cytologically, and the patients were also monitored for complications. The results were as follows. (1) The relationship between the duration of TAM therapy and the changes in MI and KPI were analyzed. It was found that, for the MI, intermediate cells (IMT) increased and superficial cells (ST) decreased during TAM administration for up to 4 years, but when the TAM therapy was continued for longer than 4 years, IMT showed a gradual decrease and ST increased gradually. The KPI values showed similar changes. (2) Studies of the endometrium (26 cases) revealed a tendency for few of the long-term administration cases to show a picture of atrophy. Of the total of 56 patients, endometrial lesions were observed in five cases (8.9%), consisting of endometrial cancer in three and cystic glandular hyperplasia in two. The mean duration of TAM administration to these five patients was 54 (+/- S.D.26.8) months. These data indicate that long-term oral administration of TAM involves the possibility of having an estrogenic effect on the vaginal epithelium and the uterine endometrium.