Cancer risk in families with hereditary prostate carcinoma - A possible link between prostate, breast, and gastric carcinoma

BACKGROUND. Little is known regarding the clinical features of hereditary p rostate carcinoma (HPC) and whether other malignancies are associated with this disease. The aim of this study was to investigate whether tumors other than prostate carcinoma aggregate in families with KPC or whether this dis ease can be considered site specific. METHODS. From 62 Swedish families with HPC, a cohort was constructed of 136 4 first-degree relatives of the men with prostate carcinoma in these famili es. Through linkage to the Swedish Cancer Register, all reported cancer bet ween 1958 and 1996 was identified. The expected number of cases was calcula ted by using the population rates in Sweden. RESULTS. A standardized incidence ratio (SIR) of 1.16 (95% confidence inter val [95% CI], 0.97-1.38] for the overall cancer risk was observed among the 1364 first-degree relatives. However, significant increased risks were not iced for gastric carcinoma (SIR, 2.78; 95% CI, 1.59-4.52), for breast carci noma in women (SIR, 1.58; 95% CI, 1.01-2.35], and for kidney carcinoma (SIR , 2.51; 95% CI, 1.15-4.77]. The excess risk for breast carcinoma was even m ore pronounced among women before the age of 65 years in families with earl ier onset prostate carcinoma (SIR, 3.64; 95% CI, 1.66-6.91). Seven families with at least two or more relatives with breast, gastric, or kidney carcin oma were identified, and, in one family, four relatives with early onset ga stric carcinoma were observed. CONCLUSIONS. In most of the families with HPC, the disease appears to be "s ite specific," with no excess of other malignancies. However, in a subset o f families, a significant aggregation of prostate carcinoma together with b reast carcinoma and/or gastric carcinoma was observed that may have been ca used by a common germline mutation in a cancer susceptibility gene. (C) 200 0 American Cancer Society.