The population of Leningrad suffered from severe starvation, cold and psychological stress during the siege in World War II in 1941-1944. We investigated the long-term effects of the siege on cancer mortality in 3,901 men and 1,429 women, born between 1910 and 1940. All study subjects were residents of St. Petersburg, formerly Leningrad, between 1975 and 1982. One third of them had experienced the siege as children, adolescents or young adults (age range, 1-31 years at the peak of starvation in [1941][1942]. Associations of siege exposure with risk of death from cancer were studied using a multivariable Cox regression, stratified by gender and period of birth, adjusted for age, smoking, alcohol and social characteristics, from 1975 to 1977 (men) and 1980 to 1982, respectively (women), until the end of 2005. Women who were 10-18 years old at the peak of starvation were taller as adults (ageadjusted difference, 1.7 cm; 95% CI, 0.5-3.0) and had a higher risk of dying from breast cancer compared with unexposed women born during the same period (age-adjusted HR, 9.9; 95% CI, 1.1-86.5). Mortality from prostate cancer was nonsignificantly higher in exposed men. The experience of severe starvation and stress during childhood and adolescence may have long-term effects on cancer in surviving men and women. ' 2008 Wiley-Liss, Inc.Key words: breast cancer; caloric restriction; prostate cancer; siege of Leningrad; starvation It has been hypothesized that caloric restriction can prevent cancer in humans, 1 including breast cancer. 2 However, the risk of breast cancer was increased in a dose-response manner in women who were exposed to a short but severe caloric restriction as children during the 1944-1945 Dutch famine.3 An earlier study of the Dutch famine also found statistically significantly increased risk of breast cancer in women exposed to dietary restriction during or shortly after the adolescent growth spurt period. 4 Further studies of men and women exposed to the Dutch famine in childhood showed that total cancer risk, exclusive of breast cancer, was not affected by the famine in women 5 and that famine was nonsignificantly associated with increased prostate cancer risk in men 6 and decreased colon cancer risk in both men and women. A study examining female survivors of the German Occupation of Guernsey 1940Guernsey -1945 found that women who remained in Guernsey during the Occupation experienced on an average delayed menarche and a nonsignificantly increased risk of breast cancer.8 Recent analyses of Jewish Holocaust survivors residing in Israel found significantly higher cancer risk in the exposed men and women, with the strongest effects seen for breast and colorectal cancers and for those exposed prior to adolescence. The starvation experienced by the population of Leningrad in 1941-1944 provides a unique opportunity to replicate and compare the results from the Dutch and other famine studies. The siege of Leningrad by German troops during World War II lasted from September 1941 to January 1944 and resulted i...