Immune system challenge reduces risk of melanoma

Immune system challenge in early life by vaccinations with vaccinia or the antituberculosis vaccine BCG and certain microbial infections appear to reduce the risk of melanoma during adulthood, investigators report in the November issue of the European Journal of Cancer.

Immune system challenge in early life by vaccinations with vaccinia or the antituberculosis vaccine BCG and certain microbial infections appear to reduce the risk of melanoma during adulthood, investigators report in the November issue of the European Journal of Cancer.Dr. Klaus F. Kolmel, at the University of Gottingen, Germany, and colleagues previously reported that childhood BCG and vaccinia vaccination reduced the risk of melanoma (see Reuters Health report October 15, 2002). Other such studies, however, have yielded conflicting results, so that the protective effects of BCG were discounted.In their current report, Dr. Kolmel’s team reports the results of the FEBrile Infections and Melanoma (FEBIM) study. Included were 603 incident cases of malignant melanoma of the skin from 11 centers in 7 countries, and 627 population control subjects without tumors, matched for age, gender, and ethnic origin within each institution.The odds ratios for melanoma were 0.40 in subjects immunized with BCG only and 0.60 among those treated with vaccinia, after adjusting for demographics and melanoma risk factors. The effect was stronger when limiting the analysis to individuals younger than 50 years of age. The effects were not additive. Based on this finding, the authors propose that widespread vaccination with vaccinia probably masked the protective effects of BCG and infectious diseases in some populations, which fueled the sentiment against BCG for cancer prophylaxis. Furthermore, the full prophylactic effect will only be realized as individuals born after widespread vaccinia and BCG vaccinations were halted reach old age.The risk was not significantly affected by influenza vaccinations within the previous 5 years. The only frequent infectious diseases to correlate significantly with reduced risk were influenza and infectious enteritis.”Vaccinia and neonatal BCG vaccinations seem to have saved many people from developing melanoma in the past and, on this basis, their re-introduction might even be justifiable,” they conclude.(Source: Eur J Cancer 2003;39:2372-2378: Reuters Health: November 25, 2003: Oncolink)