ABO Blood Groups and Multiple Cancers

Abstract

A statistically significant excess of blood group A has been found in a sample of 123 white patients with multiple primary cancers. This sample represents 2.4% of all patients with cancer in a 20-year survey. In 54% of the patients, the first and last diagnosis of cancer occurred within 3 years of one another. The relative frequency of sites of these cancers, taken individually, does not differ essentially from that of single cancers. No statistically significant difference was found between male and female with respect to the ABO system. If the excess of multiple primary cancers in patients with group A blood can be established in larger series and in different geographical locations, it will mean that the probability of another primary cancer developing is greater in the patients of blood group A.