The interaction of estrogen receptor status and race in predicting prognosis for stage I breast cancer patients.

As part of a multi-institutional breast cancer data base, 501 stage I, node negative patients have been followed prospectively with a median of 89 months. Patients were treated by a modified radical mastectomy without postoperative therapy. Estrogen receptor (ER) content of the primary tumor was determined in all cases. For the entire patient group at 10 years, the disease-free survival (DFS) rate is 72% and the overall survival (OS) rate is 85%. Both ER value and race (black versus white) were found to be significant prognostic variables for DFS (p = 0.008 and 0.02, respectively) and for OS (p = 0.0001 and 0.01, respectively). ER positive patients had a better DFS and OS rate compared with ER negative patients (74% versus 66% and 90% versus 68%, respectively). Black patients had significantly worse DFS and OS rates compared with white patients (64% versus 74% and 75% versus 86%, respectively). Statistical interaction between the ER and race variables was apparent when comparing the similar DFS for ER positive white (75%), ER negative white (72%), and ER positive black (73%) patients in contrast to a DFS of less than 42% at 10 years for the ER negative black patients. An analysis of the data for the ER negative black patients suggested that the postmenopausal ER negative black patients are at particularly high risk of recurrence and death from breast cancer.