Cancer occurrence in a cohort of patients surgically treated for peptic ulcer.

A cohort of 4107 patients treated surgically for peptic ulcer between 1955 and 1960 was followed up to determine the incidence of cancer by record linkage to the Danish Cancer Registry. A total of 930 cases of cancer were observed during 76,634 person-years. Relative risks of cancer were computed by comparison with the recorded cancer incidence in the Danish population. During the first five years after surgery the relative risk of gastric cancer was slightly increased (RR = 1.43), but 5-15 years after the operation the risk was lower than expected (RR = 0.55). Thereafter, the relative risk of gastric cancer increased steadily and increased more than twofold after 25 years. Lung cancer occurred more frequently in the cohort members than expected (RR = 1.66), but the relative risk was independent of time since surgery. Malignancies other than gastric cancer and cancers related to tobacco smoking were close to the expected numbers. The results do not support the findings of a recent British study of similar size in which increased risks were reported for cancer at other sites.