Associations between community income and cancer survival in Ontario, Canada, and the United States

Purpose: The objectives of this study were as follows: (1) to compare the m agnitude of the association between socioeconomic status (SES) and cancer s urvival in the Canadian province of Ontario with that in the United States (U.S.), and (2) to compare cancer survival in communities with similar SES in Ontario and in the U.S. Methods: The Ontario Cancer Registry provided information about all cases o f invasive cancer diagnosed in Ontario from 1987 to 1992, and the Surveilla nce, Epidemiology and End Results Registry (SEER) provided information abou t all cases diagnosed in the SEER regions of the U.S. during the same time period. Census data provided information about SES at the community level. The product-limit method was used to describe cause-specific survival, Cox proportional hazards models were used ta describe the association between S ES and the risk of death from cancer. Results: There were significant associations between SES and survival for m ost cancer sites in both the U.S. and Ontario, but the magnitude of the ass ociation was usually larger in the U.S. In the poorest communities, there w ere significant survival advantages in favor of cancer patients in Ontario for many disease groups, including cancers of the lung, head and neck regio n, cervix, and uterus. However, in upper- and middle-income communities, th ere were significant survival advantages in favor of the U.S, for all cases combined and for several individual diseases, including cancers of the bre ast colon and rectum, prostate, and bladder. Conclusion: The association between SES and cancer survival is weaker in On tario than it is in the U.S. This is due to a combination of better surviva l among patients in the poorest communities and worse survival among patien ts in the wealthier communities of Ontario relative to those in the U.S. (C ) 1999 by American Society of Clinical Oncology.