An international comparison of breast cancer survival: Winnipeg, Manitoba and Des Moines, Iowa, metropolitan areas.

Purpose: Extending previous Canadian-United States cancer survival comparisons in large metropolitan areas, this study compares breast cancer survival in smaller metropolitan areas: Winnipeg, Manitoba and Des Moines, Iowa.

Methods: Manitoba and Iowa cancer registries, respectively, provided a total of 2,383 and 1,545 women with breast cancer (1984 to 1992, followed until December 31, 1997). Socioeconomic data for each person's residence at the time of diagnosis was taken from population censuses.

Results: Socioeconomic status and breast cancer survival were directly associated in the US cohort, but not in the Canadian cohort. Compared with similar patients in Des Moines, residents of the lowest fifth of income areas in Winnipeg experienced a significant 5-year survival advantage (survival rate ratio [SRR] = 1.14). In these lowest income areas, the Canadian survival advantage was larger among women aged 25 to 64 years (SRR = 1.23), and this was observed in the middle fifth of income areas among this younger cohort (SRR = 1.11). The Canadian survival advantage even seemed apparent in the poorest neighborhoods with relatively high representations of Aboriginal people (SRR = 1.16).

Conclusion: This study replicated the finding of advantaged Canadian cancer survival in smaller metropolitan areas that had been consistently observed in larger metropolitan areas. Canada's single payer health care system seems to offer similar advantages across a number of diverse urban contexts.