A meta-analysis of cancer incidence in United States and Canadian native populations.

A meta-analytic approach was used to summarize studies of cancer incidence among Native populations in the United States and Canada. Native males and females were found to have a significantly lower incidence of cancer for all sites combined. Among Native males, kidney cancer was found to exhibit significantly elevated incidence, while significantly lower incidence was found for cancers of the colon, lung, and prostate, and for lymphomas and leukaemias. Native females were found to have significantly elevated incidence for cancers of the gallbladder, cervix, and kidney, while significantly decreased incidence was found for cancers of the colon, breast and uterus, and for lymphomas. The use of meta-analysis to integrate the findings from these studies allowed the identification of subtle differences in cancer incidence. Although these findings are not definitive, they overcome the limited numbers of site-specific cancers reported in many previous studies and are suggestive of general patterns of cancer incidence among Native populations. In addition, these results may be useful in indicating directions for future research involving specific cancer sites with elevated incidence.