Estrogen and progesterone receptors in endometrial cancer and their prognostic relevance

Three hundred and nine malignant endometrial tumors were biochemically analyzed with respect to estrogen (ER) and progesterone (PR) receptors. Fifty-seven percent of endometrial carcinomas were ER and PR positive (greater than or equal to 50 fmole/mg of cytosol protein); 24% were negative for both receptors. Five sarcomas and 16 of 21 mixed müllerian tumors were receptor negative. Receptor status correlated with clinical stage and grade of histological differentiation, but not with myometrial invasion. Anamnestic data on patients showed no differences between those with receptor-negative and receptor-positive tumors. Five-year survival rate (stage I) and median survival time (stages II-IV, recurrences) for patients with ER+/PR+ and ER-/PR+ endometrial cancer were significantly better than for ER-/PR- and ER+/PR- patients. A multivariate analysis demonstrated progesterone receptor as a significant prognostic factor next to clinical stage. Estrogen receptor had no significant prognostic relevance. A retrospective analysis of gestagen treatment and progesterone receptor status confirms the importance of PR, possibly independent of hormonal treatment.