Cutaneous melanoma at Lawrence Livermore National Laboratory: comparison with rates in two San Francisco bay area counties.

During the period 1974 through 1985, employees at Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States) were diagnosed with cutaneous malignant melanoma at approximately three times the rate of the surrounding community. We investigated two explanations for this excess: the first explanation examined was that the recorded incidence of the neighboring community underestimates actual incidence. We estimated the amount of excess attributable to underreporting by using data from a survey conducted among San Francisco Bay Area clinicians and pathologists to determine previously unrecorded occurrences. We found that underreporting has negligible impact on melanoma incidence. The second explanation examined was that heightened medical awareness of the disease among LLNL employees and their physicians has led to greater detection. We found that LLNL melanomas are thinner than those from the surrounding community and that no excess was observed if we limited our attention to thicker, more invasive melanomas.