A positive family history is used in clinical practice as an indicatio
n of increased melanoma risk, yet there are no data on the accuracy of
reported family histories of melanoma, The validity of case-reported
family history of melanoma was assessed in the course of a family and
twin study of melanoma in Queensland, Australia, conducted among the f
amilies of 2,118 melanoma cases diagnosed in Queensland between 1982 a
nd 1990. A total of 913 melanoma cases made 1,267 reports of melanoma
among their first-degree relatives. A total of 1,040 of these reports
were checked, first through relatives themselves and then, if the rela
tive also said they had had melanoma, through the relative's medical r
ecords. Medical confirmation of melanoma as the diagnosis was obtained
for 623 reports (59.9%; 95% confidence interval 56.9-62.9): a false-p
ositive reporting rate by cases of 40.1%, The level of false-positive
reporting was lower for cases under 70 years of age, for women, for ca
ses whose own diagnosis of melanoma was more than 5 years earlier, and
for cases with three or more relatives with melanoma. Media campaigns
in Queensland aimed at increasing skin cancer awareness, and confusio
n between melanoma and other more common actinic neoplasms (basal and
squamous cell carcinomas), may partly explain the high false-positive
reporting rate observed here. For this reason, it is difficult to gene
ralize these findings to northern hemisphere populations where skin ca
ncer is not such an important public health issue.