Environmental cancer and prevention on the cancer burden. Wilkinson outlines the need to distinguish between trivial and significant risks in de-
Although control of chemical carcinogenic hazards in the workplace was widely recognized during the postWorld War II era, much of the research effort of that time was directed to the identification of cancer viruses and possible vaccines. The discovery of the causal role of cigarette smoking in lung cancer was a milestone that led to expanded research on cancer causes-including chemical carcinogens and life-style factors-as a base for prevention. Later, Rachel Carson’s Silent Spring, which ded b e d ecological damage caused by misuse of commercial chemids, had a major impact on the public, who equated ecological hazards and environmental pollution with ill health, especially cancer. The politically and intellectually attractive view became widespread that human cancer could predominantly be controlled through elimination of the many potential carcinogenic chemicals in the ambient environment. Further, “cancerphobia” proved a useful adjunct to obtaining political support for the control of ecological hazards. In retrospect, it is clear that these views resulted from a misunderstanding of the major causes of human cancer, notably cigarettes. The tobacco industry continuaUy emphasized ambient air pollution as the cause of lung cancer. Further, when the public accepted the view that 80-9076of c a n m were attributable to the environment, the term “environment” was misinterpreted as applying only to chemicals. Chris Willdnson’s review (ES&Z September 1987, pp. 843-47) on the existing knowledge of the environmental causes of cancer is timely and places known and potential cancer hazards, including cultural and dietary factors, in perspective. Unfortunately, investigations of the latter are difficult bemuse definitive control methods do not yet exist for most dietary factors. Apart from drugs, occupation, and certain point source exposum, there is no evidence that the vast majority of chemical carcinogens individually or in toto (synthetic and natural) in the ambient environment at the usual levels of human exposure have had a detectable impact 992 Envimn. k i. Technol.. MI. 21, No. IO. 1987
veloping effective cancer prevention policies. In 1980 Isaac Ekrenblum, professor emeritus at the W e i i Institute in Rehovoth, Israel, concluded that only a slight reduction of the cancer burden was possible through the traditional eliminatory approach, apart from recognized public health procedures. He anticipated future efforts on preventative research that would focus on developing methods for active intervention to carcinogenic mwhanisms through chemoprevention and chemotherapy. Accarding to Berenblum, such preventative research represents the logical outcome of current basic research. Nonetheless, this view has received little attention in the regulatory circles that confuse stringent chemical controls, irrespective . . of effectiveness, with cancer prevention. The mmjuecb’on of preventative efforts may not only distort public health strategies and research efforts, but also divert national resources from more useful social goals. Prudent control of carcinogens should be based on scientific data, judgment, and common sense-not political and regulatory conveniences.
John HigdiMon is senior fellow at the
Insrilrdefor HeaIrh Policy Analysis of the G e o r g m University Medical Center and professor in the Depamnmh of Community Medicine and Parhobu. He is ah0 a research professor in pathology and epidemiolosy of the University of Norrh GuoIina. He was founding direcror of rhe International Agency on Cancer Research in Lyon, France (196681). .
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