Breast cancer in black and white women in New York State. Case distribution and incidence rates by clinical stage at diagnosis.

Case distributions and incidence rates by clinical stage at diagnosis were examined for 47,198 white and 4443 black female breast cancer cases diagnosed among residents of New York State from 1976-1981 and reported to the population-based New York State Cancer Registry. Proportions of cases diagnosed at "regional" and (especially) "metastatic" clinical stages were significantly higher in blacks versus whites, and incidence rates for "metastatic" cancers were slightly higher in blacks in some age groups (less than 60 years). The proportion of metastatic cancers differed significantly by race for single, married, and widowed cases, with younger (less than 60 years) black single women showing the highest proportions. The ranking of counties by black-white differences in per capita income was significantly associated with rankings by black-white differences in proportion of metastatic cancers. Possible explanations for this association, in terms of patient delay, and implications for cancer screening and medical care, were discussed.