Abstract
An esterized derivative progesterone was given to 27 patients who had advanced endometrial carcinoma. Objective improvement occurred in eight patients. A comparison of the patients in the responding group and those in the nonresponding (refractory) group showed an apparent biological difference in the cancer with respect to the natural pattern of growth and subsequent response to hormonal therapy. The disease in the responders was of long duration and slow growth, whereas that of the nonresponders appeared to be of short duration and rapid growth.