A Medicare-Associated Spike in U.S. Cancer Rates at Age 65, 2000-2010.

Age 65 represents a transition point where most U.S. residents begin Medicare coverage. We examined whether or not delays in medical care near this age extend to cancer diagnosis. We calculated single-year-of-age cancer incidence rates by site and stage for the most common cancer sites (i.e., prostate, female breast, lung, and colorectal) for the 2000-2010 period using data from the SEER 18 registries, and we used Poisson regression to identify a possible age-65 effect. The analysis was repeated on comparable Canadian data. Cancer rates at age 65 were found to be as much as 15% above expected in the U.S. data, with the age-65 effect strongly associated with site- and stage-specific survival. A smaller association was seen in the Canadian data. We found strong evidence that diagnosis of less severe cancers spikes at age 65. Delay of medical care prior to this age has complex policy implications.