Early diagnosis of cutaneous malignant melanoma at Lawrence Livermore National Laboratory

The Lawrence Livermore (Calif) National Laboratory (LLNL) has observed a threefold increase in incidence of cutaneous malignant melanoma (CMM) since 1972. A consultant pathologist reviewed 49 of 50 cases of CMM diagnosed from 1969 to 1984 and reclassified 4 cases; this did not significantly affect the elevated rate. A comparison of the thicknesses of CMM at LLNL from 1976 to 1984 with those from a nearby community histopathology laboratory showed that 74% of the LLNL cases were Clark level I or II, compared with 40% of the comparison laboratory cases. A matched-pair comparison controlling for age, sex, and year of diagnosis showed the LLNL cases were thinner in 58% of the pairs. The median thickness of CMMs at LLNL decreased faster than those from the comparison laboratory.