Document mqYQa7pwQaKb1y0Gye2yQJ9qk

HFM - 003535 Medicine as an art demands constant evaluation, weighing: new treatments against oldpractices, benefits against '^Jr.- risks, successes againstfailures. On occasion, the evidence,' leads to different conclusions. Nowhere is this more : f- A evident than in the management ofthe cancerpatient. OPINIONS willpresent the views ofspecialists on a wide spectrum ofcontroversial subjects. It is hoped that the ? frank expression-ofideas willprovide aframework within' which our readers mayform their own opinions. Publication does not constitute endorsement by the American Cancer Society. John H. Welsburger, Ph.D. Vice President tor Research Naylor Dana Institute For Disease Prevention American Health Foundation Valhalla, New York WARNING: FALSE CANCER CLAIMS MAY BE HAZARDOUSTO YOUR HEALTH In the fall'of 1974, a rash of newspaper and magazine headlines claimed that con taminants discovered in the lower Missis sippi Valley drinking water were associat ed with a grave risk of cancer. One ac companying illustration, playing upon the . story's shock-value, showed the face of a man drinking a glass of water, and was' captioned:. "Will he get cancer?" It is highly unlikely that the trace con taminants of drinking water would pose specific risks of cancer in the general pop-' ulation. Yet these unfounded claims, sen sationalized in the media, have greatly alarmed the public. We can say that envi ronmental factors cause about 80 percent of all human cancers, and this knowledge is grounded in both epidemiologic and This review is an adaptation of a paper entitled "Social and Ethical Implications of Claims for Cancer Hazards", published in Medical and Pediatric Oncology 3:137-140 (1977) by Alan R. Liss, Inc., 150 fifth Avenue, New York, New York 10011, experimental data. The major human can cers are due to our lifestyle, among which cigarette smoking and diet, especially high-fat, low-fiber foods and mode of cooking, are key elements. When the public is informed of newly found environmental cancer hazards. fi is imperative that the information be sup ported by definitive documentation. Scare tactics are counter-productive. If baseless: assertions continue, society will only be come deafened to bona fide evidence'of real carcinogenic hazards. Valuable re search funds and time will be diverted in useless investigations, and efforts to focus on the key causes and prevention of major human cancers will be neglected for lack of resources. The stories dealing with the "carcino genic" contaminants in the Missis$ij$ri River were spun before any scientific evi dence had even established what tljat drinking or river water contained. SciCn-. tists in the fields Of chemical carcinogen esis and cancer etiology were left wonder ing as to the nature and basis of the prob lem. Months after the announcements had alarmed the general public, a paper appeared in Science, but it merely listed the chemicals found in the water of that region; its tables gave no information concerning the amounts of those chemi cals. The carcinogenicity of the agents was implied, but not specifically discussed, in relation to the publicly announced can cer hazard. Buried in the text was a state ment that the salient contaminant was H-0 i PSJSA CA-A CANCER JOURNAL FOR CLINICIANS chloroform, and that it was present at the level of three parts per million. Chloro form had beeaahown to induce liver tu mors in mice in about 1945. While I was even for powerful carcinogens. file other question iswhethafchesu- calSwhich are carcinogenic in e*$brimentalanimals at high dose levels cat) actually at the National Cancer Institute, addi lead to cancer in man in trace amounts tional tests on this and other chlorinated even when present for an entire life span. hydrocarbons &td been started under my All known chemical carcinogens have a direction; however, detailed and carefully classical pharmacological dose response. evaluated results of these tests were not The higher the dose, the higher the cancer available at the time of the publicity. yield and the shorter the latent period, Most chemical carcinogens have one andlyice versa. To be sure, there are syner or more specific target organs. No agent is known which! leads to a generalized in crease in diverse tissues. Yet, the implica gistic effects like inhalation of asbestos and smoking of cigarettes where the as bestos enhances manyfold the rijgtdue to tion of the publicity about contaminants ; smoking alone. Nevertheless, it is most in water was that these contaminants served to increase the cancer risk at diverse sites for people using such water. unlikely that the trace contaminants of drinking water or river water would be associated with specific carcinogenicity in This is scientifically unsound extrapola the general population. In this instance, tion. Aflatoxin, for example, causes can the press reports thoroughly frightened cer mainly in the liver, in many experi the public. This does not mean we should mental species and is strongly suspected not clean up our rivers and water. This is of doing so in man. Aromatic amines in an urgent aim, meritorious for its own an occupational setting have led to cancer sake. But we should not have to use a can in the urinary bladder in man and in most cer scare to reach this goal. ;; experimental species in which these same Misguided concern about therelat|on- chemicals were tested, although in mice shipof certain food additives to cancer is they also led. to tumors of the liver. The yet another case where facts were grossly fact that this is so probably stems from misrepresented and funds needlessly the specific biochemical transformation spent- When a study performed abroad required to convert procarcinogens to the found that the food dye Red #2 had a ultimate active forms. The required en . "carcinogenic effect," well-meaning but zymes are probably similarly located in ill-informed lay groups exerted pressure organs across species lines, although ad on the United States Food and Dpig Ad mittedly, more research in this area is ministration (FDA) to re-examirifethe data necessary. Nonetheless, if chloroform and in their hands. The foreign investigation other such chlorinated hydrocarbons did claimed to have obtained evidence for cause cancer inijnan,. the!!preferred site carcinogenicity in a test where the treated would be the liyer or kidney, these are animals developed cancer in different tar among the rare cancers of man in the get sites, mostly intheendocrine-sensitive United States. organs such as pituitary, gonads mid uter Not all carcinogens are alike. The mold us. In a lifetime study, the control animals toxin and aflatoxin Bi causes liver cancer reportedly had no cancer. This is a most in rats even at one part per billion in the unusual rinding: the cancers seen in the ' diet; the flavoring agent safrole requires. experimentally treated group were the 2000 to 5000 parts per million, a consider ones normally present in aged untreated able difference!'Yet the FDA has banned controls. Yet these were the resul&.which safrole, but has set a tolerance of 15 parts apparently caused the FDA to set up an per billion for aflatoxin B,. The latter is other expensive research project to re-test a sound practical decision, for setting a this dye, even though in the micU1950's, "zero tolerance," for foods with aflatoxin . FDA! scientists of excellent standing and B i would require .a ban on many of our repute had conducted a test, seriesjhiyolv- foods! Thus, the FDA also tacitly under ing large numbers of Jmice and rah; and writes the existence of "no effect" levels had concluded that this dye presented no VOL 28. NO. 2 MARCH/APRIL1976 'hh; V 09S 5: