Trends in age-specific and age-standardized mortality from 10 major cancer sites and total cancer mortality in the USSR were analyzed for the period 1965-1990, on the basis of the World Health Organization mortality database. Gastric cancer mortality declined substantially. Still, these rates were among the highest registered in the world, and in 1990 stomach cancer accounted for over 85,000 deaths, being the second cause of cancer death (and the first one until 1980); further, there was some indication of a levelling of the declines in gastric-cancer rates for both sexes over most recent calendar years. Likewise, uterine-cancer mortality declined between 1965 and 1985, but there was no further decline over the last 5 years. Upward trends were registered for cancers of the intestine, of the breast and of the prostate. Mortality from these neoplasms, however, was still comparatively low by worldwide standards. Leukaemia rates were stable in both sexes. Substantial rises were observed for cancers of the oral cavity and pharynx, larynx and, chiefly, lung. Even more unfavourable was lung-cancer mortality in young and middle-aged males, since the truncated rate of 121/100,000 in 1990 was higher than the values reached by countries like England and Wales or Finland even at the top of their epidemic in the 1960s, and trends in the USSR were still upwards. Thus, total cancer mortality was 176/100,000 males in 1965, declined to 170 in 1970, but increased thereafter, particularly over the last decade, to reach 203/100,000, i.e., one of the highest rates on a worldwide scale. Among females, the overall cancer mortality rate declined between 1965 and 1975, but rose thereafter to a value intermediate on a worldwide scale. These recent unfavourable trends of cancer mortality in the USSR indicate that, in the absence of adequate intervention, particularly on the tobacco-related cancer epidemic, overall cancer mortality will continue to rise in the foreseeable future.
A favorable role of fruit and vegetables on colorectal cancer risk has been related to the antioxidant properties of their components. We used data from an Italian case-control study including 1,953 patients with incident, histologically confirmed colorectal cancer (1,225 colon and 728 rectal cancers). Controls were 4,154 patients admitted to hospital for acute, non-neoplastic conditions. A reproducible and valid food frequency questionnaire was used to assess subjects' usual diet. Total antioxidant capacity (TAC) was measured using Italian food composition tables in terms of ferric reducing-antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and total radical-trapping antioxidant parameter (TRAP). We estimated the odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) through multiple logistic regression models, including terms for potential confounding factors, and energy intake. TAC was inversely related with colorectal cancer risk: the OR for the highest versus the lowest quintile was 0.68 (95% CI, 0.57-0.82) for FRAP, 0.69 (95% CI, 0.57-0.83) for TEAC and 0.69 (95% CI, 0.57-0.83) for TRAP. Corresponding values, excluding TAC deriving from coffee, were 0.75 (95% CI, 0.61-0.93) for FRAP, 0.76 (95% CI, 0.61-0.93) for TEAC and 0.71 (95% CI, 0.57-0.89) for TRAP. The inverse association was apparently-though not significantly-stronger for rectal than for colon cancer. This is the first case-control study indicating consistent inverse relations between dietary TAC and colorectal cancer risk.
Dear Sir, ’We derived our pooled risk estimate of mesothelioma from nonoccupational exposure to asbestos from a previous publication authored by some of us, in which the methods for the meta-analysis were described in detail (1). In addition to the summary relative risk, our estimate of the number of non-occupational mesothelioma cases was based on frequencies in the populations experiencing exposures comparable with those in which the relevant epidemiological studies have been carried out. This parameter is subject to great uncertainty, and as a result, we selected it in our commentary as an example of the possible lack of temporal correspondence between risk and exposure data. Mirabelli and Merler suggest a different approach to estimate the number of mesothelioma cases attributable to non-occupational exposure to asbestos, based on the reasonable assumption that all cases with a recorded exposure are attributable to it. Their results of the Italian mesothelioma registry are of interest, and a recent analysis of the same data reported that 4.2% of cases in the registry had environmental asbestos exposure (2). It should be kept in mind that, although all reasonable efforts should be made to reduce and eliminate environmental asbestos exposure, this would have a limited effect on the overall cancer burden. Mesothelioma accounts each year for 1000 cases out of 300 000 total cancer cases (0.3%) in a country such as Italy, and hence 10% of mesothelioma cases represent 0.03% of all cancer cases.
Hormone replacement therapy in menopause has been associated with a moderate increase in ovarian cancer risk. Data on combined estrogen-progestin therapy, based on one randomized trial, two cohort and four case-control studies, do not provide definite evidence of an association between combined hormone replacement therapy and ovarian cancer. These data do not suggest, however, substantial differences between the effect of estrogen only or unspecified hormone replacement therapy and combined hormone replacement therapy on ovarian cancer risk.
