Occurrence of cancer in Alzheimer and elderly control patients: an epidemiologic necropsy study

Epidemiologic necropsy provides an accurate measure of the occurrence rates of diseases. To determine the occurrence of cancer in Alzheimer patients as well as in non-Alzheimer elderly controls, we examined autopsy reports of 575 control and 71 Alzheimer cases aged 50-100 years for histologic evidence of cancer. We compared expected rates of cancers calculated from the National Cancer Institute's Surveillance, Epidemiology and End Result (SEER) Program data to rates observed at autopsy using a chi-squared test. To determine whether there was an association between the occurrence of cancer and Alzheimer disease, we compared rates for all cancer and three specific cancers in Alzheimer and control patients using an odds ratio test. We found from fourfold to 98-fold more cancer in Alzheimer patients and controls than that expected from SEER data. There was no statistical difference in the autopsy incidence of total, lung, or prostate cancer between Alzheimer patients and controls. However, the occurrence of pancreatic cancer was 6.7-fold higher in Alzheimer patients than in control subjects. Controlling for multiple comparisons, the odds ratio for pancreatic cancer in Alzheimer's disease was significantly higher than in controls (p < 0.001). Our results indicate that cancer occurs more frequently than expected in both Alzheimer patients and control subjects. In addition, there may be an association between the occurrence of certain cancers and Alzheimer's disease.