Progesterone Receptors in Breast Cancer

Sixty-six women who had received hormonal therapy for advanced disease were assessed for objective response to treatment. Another 51 patients who had received chemotherapy were similarly studied. Progesterone receptor was of no value as a predictor of patients unlikely to respond to hormone therapy, though it may have a role in predicting patients likely to respond favourably. The addition of progesterone receptor data to oestrogen receptor data may increase prediction of response in the ER+ range but clinicians should be cautious in their interpretation of progesterone receptor results in the ER- range. Progesterone receptor was of no value in predicting response to chemotherapy in this series. Analysis of survival data of 1731 women with primary breast cancer showed a highly significant trend toward longer survival in patients with progesterone receptor positive tumours than in those with receptor negative tumours (P less than 0.001). This trend was evident in both pre- and post-menopausal women. Even though the prognostic discrimination provided by progesterone receptor was correlated with that of oestrogen receptor, the addition of progesterone receptor data to oestrogen receptor data significantly improved prediction of survival (P less than 0.05).