Income and long-term breast cancer survival: comparisons of vulnerable urban places in Ontario and California.

Effects of socioeconomic status on the long-term survival of 808 women with node-negative breast cancer in Canada and the United States were observed. Ontario and California samples diagnosed between 1988 and 1990 were followed until 2006. Socioeconomic data were taken from population censuses. Compared with their California counterparts, residents of low-income urban areas in Ontario experienced a significant 15-year survival advantage (RR = 1.66 [95% CI: 1.00, 2.76]). In these and other vulnerable, lower-middle- to working-class neighborhoods, significantly more Ontario residents gained access to adjuvant radiation therapy (RR = 1.75 [1.21, 2.53]) which seemed associated with better long-term survival (RR = 1.36 [0.99, 1.86]). This stage-adjusted, historical cohort analysis suggests much greater cancer care equity in Canada than in the United States.