Familial cancers in a nationwide family cancer database: Age distribution and prevalence

We calculated sex- and age-specific familial relative risks (FRRs) of cance r in offspring of cancer probands at 19 male and 20 female cancer sites, ba sed on the nationwide Family Cancer Database from Sweden. The proportion of familial cancers among all cancers was also determined. The database conta ined 550 000 primary cancers. The familial risks at known sites: colon, bre ast, ovary, testis, skin (melanoma), nervous system, thyroid and other endo crine glands were confirmed. The FRR of thyroid cancer exceeded any other c ancer and was over twice as high for male as for female offspring, and appe ared to constitute an early- and late-onset component. Novel register-based findings were familial risks in cervical and uterine cancer, and in male o ffspring of male probands kidney and skin (mainly squamous cell) cancer. Fa milial risks were noted also for lung cancer, lymphoma and leukaemia but th ey may have largely environmental causes. The proportion of familial cancer s depended on the site, ranging from 11% in prostate to 8.7% in female brea st and to well below 1% at many sites. (C) 1999 Elsevier Science Ltd. All r ights reserved.