OBJECTIVE:To compare the efficacy and safety of medroxyprogesterone or dydrogesterone combined with hystero-scopic electrosurgery in the treatment of early estrogen-dependent endometrial cancer. METHODS:42 patients with early estro-gen-dependent endometrial cancer were randomly divided into medroxyprogesterone group (21 cases) and dydrogesterone group (21 cases). All patients received hysteroscopic electrosurgery. Medroxyprogesterone group received 100 mg Medroxyprogesterone acetate tablet,3 times a day. Dydrogesterone group received 100 mg Dydrogesterone tablet,twice a day. The treatment course for both groups was 6 months. Clinical efficacy,carbohydrate antigen CA125(CA125),body mass and the incidence of adverse reac-tions in 2 groups were observed. RESULTS:After 3 months of treatment,the total effective rate in dydrogesterone group was sig-nificantly lower than medroxyprogesterone group,the difference was statistically significant(P<0.05). After 12 months,the total effective rates in 2 groups were significantly higher than 3 months,the difference was statistically significant(P<0.05),but there was no significant difference between 2 groups (P>0.05). Before treatment,there were no significant differences in CA125 and body mass in 2 groups (P>0.05). After 3 and 12 months,CA125 levels in 2 groups were significantly lower than before,12 months was lower than 3 months,and dydrogesterone group was higher than medroxyprogesterone group after 3 months,the differ-ences were statistically significant (P<0.05),but there were no significant differences between 2 groups after 12 months (P>0.05). After treatment,the body mass in medroxyprogesterone group was significantly higher than before,the difference was statis-tically significant (P<0.05);while there was no significant difference in dydrogesterone group before and after treatment (P>0.05). And the incidence of adverse reactions in dydrogesterone group was significantly lower than medroxyprogesterone group,the difference was statistically significant(P<0.05). CONCLUSIONS:The short-term efficacy of medroxyprogesterone combined with hysteroscopic electrosurgery is superior to dydrogesterone combined with hysteroscopic electrosurgery in the treatment of early estro-gen-dependent endometrial cancer,but medroxyprogesterone combined with hysteroscopic electrosurgery shows high incidence of adverse reactions. Long-term effects of both Dydrogesterone and Medroxyprogesterone are equivalent.