Risk of incident and fatal melanoma in individuals with a family history of incident or fatal melanoma or any cancer

Background A family history of melanoma is associated with an increased risk of melanoma and probably of other, discordant cancers. Limited data are available on familial mortality in melanoma. If fatal forms of melanoma were associated with fatal forms of melanoma or of some other cancers, only studies on familial mortality rather than on familial incidence might be able to detect them. Furthermore, estimates on familial aggregation based on mortality are free from bias of overdiagnosis. Objectives The aim of this study was the estimation of familial aggregation of concordant melanoma and of melanoma and any other cancers based both on incidence and on mortality. Methods We used the nationwide Swedish Family-Cancer Database to calculate standardized incidence ratios (SIRs) for incident melanoma for relatives of any cancer patients and standardized mortality ratios (SMRs) for death from melanoma for relatives of individuals who died from any other cancer. Similar risks were determined for any common cancer when relatives were affected by melanoma. Results For concordant melanoma, familial incidence equalled familial mortality, SIR = SMR. Familial clustering (SIRs increased) of melanoma and oesophageal, colorectal, breast, prostate, kidney, nervous system and connective tissue cancers and myeloma and leukaemia was observed. The SMRs for pancreatic and nervous system cancers were increased in relatives whose parents had died from melanoma. Conclusions These data should encourage a search for fatal subtypes of familial cancer, which may eventually have clinical implications.