Objectives: This study examined whether socioeconomic status has a differential effect on the survival of adults diagnosed with cancer in Canada and the United States.
Methods: The Ontario Cancer Registry and the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program provided a total of 58,202 and 76,055 population-based primary malignant cancer cases for Toronto, Ontario, and Detroit, Mich, respectively. Socioeconomic data for each person's residence at time of diagnosis were taken from population censuses.
Results: In the US cohort, there was a significant association between socioeconomic status and survival for 12 of the 15 most common cancer sites; in the Canadian cohort, there was no such association for 12 of the 15 sites. Among residents of low-income areas, persons in Toronto experienced a survival advantage for 13 of 15 cancer sites at 1- and 5-year follow-up. No such between-country differentials were observed in the middle- or high-income groups.
Conclusions: The consistent pattern of a survival advantage in Canada observed across various cancer sites and follow-up periods suggests that Canada's more equitable access to preventive and therapeutic health care services is responsible for the difference.