Screening program reduced melanoma mortality at the Lawrence Livermore National Laboratory, 1984 to 1996.

BACKGROUND: Worldwide incidence of cutaneous malignant melanoma has increased substantially, and no screening program has yet shown reduction in mortality. We evaluated results of an educational campaign designed to promote self-examination and targeted screening at the Lawrence Livermore National Laboratory (LLNL). METHODS: Thickness and crude incidence of melanomas detected during 3 phases of increasing melanoma surveillance were studied. These periods were: (1) preawareness (1969-1975), (2) early awareness of increased melanoma risk (1976-1984); and (3) screening program (1984-1996). Melanoma mortality was derived from data recorded in the National Death Index search. The expected annual number of deaths from melanoma among LLNL employees was calculated by using California mortality data matched by age, sex, and race/ethnicity and adjusted to exclude deaths from melanoma diagnosed before the program began or before employment at LLNL. RESULTS: Crude incidence of melanomas thicker than 0.75 mm decreased during the 3 periods from 22.1 to 15.13 to 4.62 cases per 100,000 person-years (P = .001 by chi-square for trend) with the larger decrease from the active screening program. The crude incidence of melanoma measuring less than 0.75 mm in thickness increased and then decreased slightly without a significant linear trend, and crude incidence of in situ melanoma increased substantially. No eligible melanoma deaths occurred among LLNL employees during the screening period, whereas the expected number of deaths was calculated to be 3.39 deaths (P = .034). LIMITATIONS: The study design was not randomized or controlled. The methodology for adjusting expected mortality for the exclusion of employees diagnosed with melanoma before the screening period was devised for this study. DISCUSSION: Increasing community awareness of melanoma was associated with a progressive decreasing incidence of thicker melanoma. The education, self-examination, and selective program generated the larger reduction in incidence of melanoma thicker than 0.75 mm. This campaign decreased the melanoma-related mortality to zero. The statistically significant decrease in mortality persisted for at least 3 years after employees retired or otherwise left the laboratory.

Cancer incidence rates among Lawrence Livermore National Laboratory (LLNL) employees: 1974-1997.

BACKGROUND: In the mid-1970's an excess of malignant melanoma of the skin was noted among employees at the Lawrence Livermore National Laboratory (LLNL). A 1984 cancer incidence study showed a non-significant excess of total cancers among female employees with significant excesses for melanoma, rectum and anus, and salivary gland cancers. For male employees, there was a non-significant deficit of total cancer with significant excesses in melanoma and non-brain nervous system cancers. This paper reports the results of a surveillance effort to update our understanding of the patterns of cancer incidence in this population. METHODS: We used California Cancer Registry (CCR) data to ascertain employees who had worked for six or more consecutive months at LLNL during the 24-year period of 1974 through 1997 who were diagnosed weith cancer during that time frame. We used the Standardized Incidence Ratio (SIR) in our analyses. RESULTS: There were 17,785 employees who provided 186,558 person-years of observation: 145,203 were from males and 41,355 were from females. The CCR, through its linkage techniques, identified 541 individuals with invasive cancer and 96 with in situ cancer. A total of 404 males had invasive cancer and 33 had in situ cancer whereas there were 137 females with invasive cancer and 63 with in situ cancer. The SIR for invasive cancer in males was 69 (95% CI 62-76). The overall cancer SIR for males was unaffected by calendar time. There were only two invasive cancer sites with significant excess: melanoma and cancer of the testes. For eight categories or cancer sites, we found a statistical deficit in cancer incidence. The most striking deficit occurred in cancer of the lungs and bronchus with a SIR of 36 (95% CI 26-50). The SIR for invasive cancer in females was 80 (95% CI 67-94). The overall cancer SIR for females decreased over calendar time. There was a statistically significant deficit for cancers of the female genital organs. There were 84 cases of invasive and in situ melanoma in both genders. Time-trend analyses for melanoma showed a significant excess during the years 1974-1985 but a reduction to community rates from 1986 through 1997. There were 21 individuals with testicular cancer with a SIR of 207 (95% CI 129-317). There were no differences in age at diagnosis or cell type with the comparison population. We analyzed the data using the same radiosensitive cancer categories used in the 1984 study. There were no increases in SIRs in any of these categories. CONCLUSIONS: We found that the LLNL employees had less cancer than expected with males having relatively fewer cancers than females. The lung cancer rate for males was remarkably low. Since 1986 the melanoma rates resemble the community rates. Testicular cancer rates are modestly elevated and appear to have been so for the past 20 years. Lifestyle patterns, including smoking, and cancer screening activities are probably important contributors to the observed low cancer rates.

Three somatic genetic biomarkers and covariates in radiation-exposed Russian cleanup workers of the chernobyl nuclear reactor 6-13 years after exposure.

Three somatic mutation assays were evaluated in men exposed to low-dose, whole-body, ionizing radiation. Blood samples were obtained between 1992 and 1999 from 625 Russian Chernobyl cleanup workers and 182 Russian controls. The assays were chromosome translocations in lymphocytes detected by FISH, hypoxanthine phosphoribosyltransferase (HPRT) mutant frequency in lymphocytes by cloning, and flow cytometic assay for glycophorin A (GPA) variant frequency of both deletion (N/Ø) and recombination (N/N) events detected in erythrocytes. Over 30 exposure and lifestyle covariates were available from questionnaires. Among the covariates evaluated, some increased (e.g. age, smoking) and others decreased (e.g. date of sample) biomarker responses at a magnitude comparable to Chernobyl exposure. When adjusted for covariates, exposure at Chernobyl was a statistically significant factor for translocation frequency (increase of 30%, 95% CI of 10%-53%, P = 0.002) and HPRT mutant frequency (increase of 41%, 95% CI of 19%-66%, P < 0.001), but not for either GPA assay. The estimated average dose for the cleanup workers based on the average increase in translocations was 9.5 cGy. Translocation analysis is the preferred biomarker for low-dose radiation dosimetry given its sensitivity, relatively few covariates, and dose-response data. Based on this estimated dose, the risk of exposure-related cancer is expected to be low.