The relative risk of developing cancer after partial gastrectomy for b
enign ulcer disease, expressed as the standardized incidence ratio, wa
s examined in a population-based cohort comprising 6459 patients opera
ted on between 1950 and 1958. Follow-up to 1983 revealed 1112 patients
with cancer versus 1128 expected cases (relative risk 1.0 (95 per cen
t confidence interval (c.i.) 0.9-1.1)). The overall risk increased ove
r time; it was higher in younger than in older patients but was not re
lated to sex, surgical procedure (Billroth I or II gastrectomy) or dia
gnosis at operation (duodenal or stomach ulcer). There was an increase
d risk for lung cancer (relative risk 1.5 (95 per cent c.i. 1.2-1.7)),
for oesophageal cancer in patients operated on for stomach ulcer (rel
ative risk 2.2 (95 per cent c.i. 1.0-4.2)) and for cancer of the bilia
ry tract in men (relative risk 1.9 (95 per cent c.i. 1.2-2.9)) and in
those operated on for duodenal ulcer (relative risk 1.7 (95 per cent c
.i. 1.0-2.8)). The overall risk for genital cancer in women was unchan
ged but decreased with increasing duration of follow-up and age. Cance
rs of the nervous system occurred less frequently than expected (relat
ive risk 0.5 (95 per cent c.i. 0.3-0.8)), while the risk for cancer of
the buccal cavity, lymphatic and haematopoietic systems, pancreas, br
east, prostate, kidney and bladder was unchanged.