PROGESTERONE THERAPY FOR ENDOMETRIAL CARCINOMA REDUCES CELL-PROLIFERATION BUT DOES NOT ALTER APOPTOSIS

BACKGROUND. Although the anticancer effects of progesterone therapy fo r patients with endometrial carcinoma are widely acknowledged, a detai led assessment of the resultant morphologic alterations in tumor tissu e kinetics has hitherto been lacking. METHODS, Biopsy and hysterectomy specimens of 14 endometrial carcinomas (endometrioid-type) before and during progesterone therapy were studied to clarify changes in apopto sis and cell proliferation and their relation to morphologic alteratio ns. The extent of squamous differentiation within tumor lesions was al so examined. RESULTS. In the good-response group, tumor cells took on characteristics of normal endometrial gland cells in the secretory pha se. A positive correlation between reduction in the mitotic index and the degree of morphologic alterations during hormone therapy was obser ved, but the frequency of apoptotic cells did not vary. In both the go od-response and poor-response groups, development or enlargement of sq uamous areas was observed, in comparison with the initial biopsy speci mens. CONCLUSIONS, These results suggest that prolonged progesterone a dministration can suppress cell proliferation in endometrial carcinoma s through tumor cell differentiation without alterating apoptosis, res ulting in a shift in tissue kinetics toward a relative predominance of cell deletion. In addition, increases in the occurrence of squamous a reas within tumors do not always appear to be related to treatment eff icacy. (C) 1998 American Cancer Society.