Are Increasing 5-Year Survival Rates Evidence of Success Against Cancer? a Reexamination Using Data from the U.S. And Australia
19 Pages Posted: 7 Jun 2010 Last revised: 20 Sep 2014
Date Written: June 2010
Previous investigators argued that increasing 5-year survival for cancer patients should not be taken as evidence of improved prevention, screening, or therapy, because they found little correlation between the change in 5-year survival for a specific tumor and the change in tumor-related mortality. However, they did not control for the change in incidence, which influences mortality and is correlated with 5-year survival. We reexamine the question of whether increasing 5-year survival rates constitute evidence of success against cancer, using data from both the U.S. and Australia. When incidence growth is controlled for, there is a highly significant correlation, in both countries, between the change in 5-year survival for a specific tumor and the change in tumor-related mortality. The increase in the relative survival rate is estimated to have reduced the unconditional mortality rate by about 15% in the U.S. between 1976 and 2002, and by about 15% in Australia between 1984 and 2001.While the change in the 5-year survival rate is not a perfect measure of progress against cancer, in part because it is potentially subject to lead-time bias, it does contain useful information; its critics may have been unduly harsh. Part of the long-run increase in 5-year cancer survival rates is due to improved prevention, screening, or therapy.
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