Evaluation of the predictive power of progesterone receptor levels in primary breast cancer: a comparison with other criteria in 559 cases with a mean follow-up of 74.8 months. The Breast Cancer Prognostic Study Associates.

: A total of 559 women with primary breast cancer treated by modified radical mastectomy were followed for a mean of 74.8 months to evaluate the relationship of sex hormone receptor content in the tumor with time to first recurrence and to death due to breast cancer. The prognostic significance of progesterone receptor (PgR) status was evaluated in terms of estrogen receptor (ER) status, age (less than or equal to 49 years, greater than or equal to 50 years), extent of lymph node involvement, tumor size, and morphologic characteristics. Overall, patients with PgR positive (greater than 9 femtomoles/10 mg wet weight tissue) tumors experienced a significantly longer period to both first recurrence and death due to breast cancer, but this advantage was restricted to those whose cancer had metastasized to their axillary lymph nodes. For women with nodal involvement, the extent of this involvement and the size of the primary lesion had the greatest predictive value followed by nuclear grade and PgR status. In these node-positive patients, PgR positivity, although strongly associated with ER positivity, had a greater predictive value than that of the estrogen receptor per se.