Relationship of estrogen and progesterone receptors to prognosis in breast cancer.

To ascertain the role of estrogen (ER) and progesterone (PR) receptors as prognostic indicators of resectable breast cancer, the records of 204 patients were analyzed whose receptor studies were done at the Maimonides Medical Center from 1975 to 1983. All patients had radical or modified radical mastectomies and did not show any evidence of distant metastases at the time of operation. Median follow-up was 37 months. An additional 117 patients received some form of adjuvant therapy, mainly chemotherapy, and were analyzed separately. Life table analysis using the log rank test for measuring significance, and a Cox multivariate analysis was performed. At 48 months, 22% of the ER positive (ER+) group versus 33% of the ER negative (ER-) group had recurred as compared to 16% and 35% for the PR+ versus PR- groups, respectively. Life table analysis of the disease free interval (DFI) showed that the difference between the ER+ and ER- groups was not significant (p greater than 0.1), while the difference in DFI between the PR+ and PR- groups was significant (p less than 0.05). Multivariate analysis revealed that the most important factors in predicting the DFI were nodal status (p less than 0.001), tumor size (p less than 0.025), and progesterone receptor status (p less than 0.05). Estrogen receptor status was not found to be significant. In conclusion, PR- patients have a shorter DFI than PR+ patients and that PR status is a more valuable predictor of DFI than ER status.