Socioeconomic factors and race in breast cancer recurrence and survival

The relation of breast cancer recurrence and overall survival to age, level of estrogen receptors, number of positive lymph nodes, obesity, race, socioeconomic status, and tumor size at the time of diagnosis was considered for 1,392 breast cancer patients (253 black, 1,132 white, and 7 of other races) entered into two multi-institutional prospective clinical trials. Baseline for the first trial was 1974-1979, and that for the second was 1980-1985; follow-up for this report ended in August 1990. Univariately, all factors except age and obesity were significantly related to disease-free survival, and all except age were significantly related to overall survival. A multivariate analysis using Cox's proportional hazards model indicated that a greater number of positive lymph nodes, a larger tumor diameter, lower socioeconomic status, and negative estrogen receptors were significantly related to shorter disease-free survival. After adjustment for socioeconomic status, race ceased to be a significant indicator of either disease-free survival or overall survival. Patients of either race who are of a lower socioeconomic status are more likely to have a recurrence and to die of breast cancer.