A case-control study in the population of the Eastern Black Sea region of T
urkey was conducted to learn the incidence of stomach cancer in the sibling
s of patients with gastric carcinoma, Among 1240 patients with gastric carc
inoma, 168 had sibling(s) with a history of stomach cancer versus 19 cases
in the control group matched according to age and gender (OR 10.07, P < 0.0
001). The frequency of a history of stomach cancers and cancer of other org
ans in first- to third-degree relatives was 60.7% and 38.0%, respectively,
of 168 sibling cases with gastric carcinoma (P < 0.0001). Fifty-two point t
hree per cent of sibling cases having a history of cancer in other organs i
n their relatives also reported stomach cancer in the same-degree relatives
. The number of stomach cancers in the first- to third-degree relatives of
sibling cases was higher than the number of other organ cancers in the same
-degree relatives (P < 0.01). Familial clustering of stomach cancer was rep
orted in 12.5% of sibling cases. The study of stomach cancer history in the
siblings suggests: the presence of a genetic susceptibility, high risk of
the disease occurrence in the siblings of patients, higher predisposition t
o gastric than to other organ cancers in the relatives, and not infrequent
familial clustering, (C) 2000 Lippincott Williams & Wilkins.