Familial and hereditary prostate cancer in southern Sweden. A population-based case-control study

The objectives of this study were to investigate the effect of family histo ry on prostate cancer risk, to estimate the incidence of hereditary prostat e cancer in southern Sweden and to assess the reliability of self-reported family history of prostate cancer. The study included consecutive prostate cancer patients and age-matched control subjects from a geographically defi ned population. The controls consisted of 1 male patient with malignant mel anoma or non-Hodgkin's lymphoma and 1 male from the community per prostate cancer case. Family history was assessed with questionnaires, and diagnoses of fathers and brothers of cases were validated by the Southern Swedish Re gional Tumour Registry. Among fathers and brothers whose names and birth da tes were available, 56 (92%) of the 61 reported prostate cancer diagnoses w ere verified. Fifteen per cent of 356 cases and 5.0% of 712 controls report ed at least 1 case of prostate cancer among their brothers or fathers, givi ng a relative risk of 3.2 (95% confidence interval 2.1-5.1). The relative r isk increased with decreasing age at diagnosis of the patient. Based on the pedigree, 3.1% of the 356 patients were classified as having hereditary pr ostate cancer. This proportion was significantly higher among patients diag nosed before the age of 60 years (7.1%) than among older patients (2.2%). W e conclude that there is a substantially increased risk of prostate cancer for sons and brothers of prostate cancer patients. The risk increases with decreasing age at diagnosis of the patient as an effect of a higher prevale nce of hereditary prostate among early onset cases. Furthermore, we found s elf-reported family history of prostate cancer to be a valid estimate of th e true incidence of prostate cancer in fathers and brothers of men with pro state cancer. (C) 1999 Elsevier Science Ltd. All rights reserved.