An international comparison of cancer survival: relatively poor areas of Toronto, Ontario and three US metropolitan areas.

Abstract

This study of cancer survival compared adults in Toronto, Ontario and three US metropolitan areas: Seattle, Washington; San Francisco, California; and Hartford, Connecticut. It examined whether socioeconomic status has a differential effect on cancer survival in Canada and the United States. The Ontario Cancer Registry and the National Cancer Institute's Surveillance, Epidemiology and End (SEER) programme provided a total of 23,437 and 37,329 population-based primary malignant cancer cases for the Toronto and US samples, respectively (1986-1988, followed until 1994). Census-based measures of socioeconomic status were used to ecologically control absolute income status. Among residents of low-income areas, persons in Toronto experienced a 5 year survival advantage for 13 of 15 cancer sites [minimally one gender significant at 95 per cent confidence interval (CI)]. An aggregate 35 per cent survival advantage among the Canadian cohort was demonstrated (survival rate ratio (SRR) = 1.35, 95 per cent CI= 1.30-1.40), and this effect was even larger among younger patients not yet eligible for Medicare coverage in the United States (SRR = 1.46, 95 per cent CI = 1.40-1.52). Systematically replicating a previous Toronto-Detroit comparison, this study's observed consistent pattern of Canadian survival advantage across various cancer sites suggests that their more equitable access to preventive and therapeutic health care services may be responsible for the difference.