The epidemiology of cancer: An overview

Abstract

The contribution of cancer epidemiology to cancer prevention is in identifying risk factors, providing clues for understanding etiologic mechanisms, and in developing the scientific rationale for the effective application of preventive measures. Cancer mortality, incidence, and survival trends over 25 years (1950-1974) in the United States are reviewed for 12 selected sites in adult men and women. If both incidence and mortality for a specific cancer site remain unchanged or change proportionately over a period of years, no major change in survival should be anticipated. The patterns of occurrence and their etiologic implications are reviewed separately in American blacks and in children and young adults. The studies of geographic pathology and of various migrant populations have provided observational "experiments of nature" that have facilitated our understanding of cancer etiology by stimulating important paths of research.

Epidemiological investigations on neuroblastomas in Denmark 1943-1980

“…It is therefore believed that the present estimates reflect the true trends in incidence of childhood neuroblastoma in Denmark during the period 1943-80. Some of this rise in incidence would be consistent with the suggestion that environmental carcinogens of importance in the induction of neuroblastoma may have increased (Schottenfeld, 1981). The investigation revealed that the incidence as well as the mortality is significantly lower for the children of self-employed parents than for children in other socio-economic groups.…”

“…In Denmark the social stresses in this maternal age group are higher than in other maternal age groups (high frequency of extramarital births, lower socio-economic class). One may speculate that some of the children born to mothers under 20 years have been highly exposed to carcinogens in early gestational life, since the incidence in the first year of life is higher (Miller, 1977;Rice, 1973;Schottenfeld, 1981). However, aside from lower socio-economic circumstances, this study revealed no specific risk factors [as for example a higher alcohol consumption during pregnancy (Seeler et al, 1979)].…”

“…In Denmark the living conditions for children born to self-employed parents are generally the best and the percentage of extra-marital births is very low in the group of selfemployed. Social class factors have also been revealed for other types of childhood neoplasms (Gutensohn et al, 1982;Ramot & Magrath, 1982;Schottenfeld, 1981). During the study period the percentage of children of self-employed parents fell from 41 % to 19%.…”

“…Furthermore, diagnostic techniques have undoubtedly been improved, for example by the introduction of the urinary VMA excretion as a diagnostic tool in the sixties. The frequency of autopsy for death statistics is significant (Juel, 1981); however, it seems difficult to believe that the ominous symptoms of cancer could have been overlooked during the first part of the study period, so that children were incorrectly registered as dying of non-neoplastic diseases, even though the possibility cannot be dismissed (Schottenfeld, 1981;Young & Miller, 1975). The present study demonstrates that neuroblastoma cases which might have been wrongly attributed to death by other cancers, should be sought amongst children who died before their 5th year.…”

Pathogenesis of Human Urinary Bladder Cancer

“…Bladder cancer in most humans appears to be multifactorial in origin and multistage in evolution (1)(2)(3)(4)(5)(6)(7)(8). Our natural environment may contain a number of factors important in the etiology of bladder cancer (5,6,9).…”