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I Appendix C TRANSLATION: Schmahl. D.: IP INTERVIEW: LUNG CANCER DUE TO PASSIVE SMOKING? NO -- ALL JUST SPECULATIONI (AP-Gesprach: Lungenkrebs durch Passivrauchen7 Nein --alles aur Spekulationt) ilrtzliche Praxis. Vol. 60, No. 92, p. 2,867, 1988. Professor Dietrich Scbmahl: In terms of tozicology. an elevated risk is extremely unlikely -- furthermore, the nose acts as a filter to protect against hazardous substances. A critical examination of the epidemiological data yields no indication of an increased risk of lung cancer due to passive smoking, and such a risk also appears extremely unlikely from the aspect of toxicology. This is the opinion of Professor Dietrich F. X. Schauhl, executive director of the Toxicology and Chesntherapy Institute of the German Cancer Research Center in Heidelberg, in an iP interview with Kirk Rohvedder. The bronchial carcinoma of the smoker has quite characteristic preliminary stages that no one has been able to detect in passive smokers, according to Dr. Schmlhl. AP: Smoking has been ^ subject of your research and clinical activity for nearly 35 years. How important is the matter of passive smoking in your work? Schmahl: Given the significance of active smoking, passive smoking has never been as important to me as active smoking -- although the subject con- tinually recurs in discussions. I am personally convinced that a gross imbal- ance develops when the discussion unfortunately turns from the risks of active smoking to those of passive smoking. In my estimation, that is a falsifica- tion of the health situation. A8: Yet this shift in the discussion =istakably occurs today. How can this be explained? Schmahl: There is no doubt that smoking is harmful to the smoker. In our free society, however, a person has the right to harm himself. But if it is alleged that a smoker harms not only himself, but others as well, then this PA N 0

cological aspect, to which I can contribute something. an elevated risk appears to be iztremely unlikely. Ap: Can you be more specific? Schmahl: Nore or less all epidemiological studies of active smokers emphasize that a risk of bronchial cancer exists essentially for the smoker who inhales, that is. who smokes through the lungs. For a smoker who only puffs, the risk is approximately comparable to that for a nonsmoker. This applies to swst pipe and cigar smokers. But precisely these puffing active smokers are in fact themselves the most extreme passive smokers. And for them -- as all studies on active smoking have demonstrated -- the risk of lung can- cer is no higher than for nonsmokers. SF: That is a logical argument based on epidemiological data. Nov let us discuss the toxicological aspects. Schmghl: Apparently the carcinogenic substances that we assume are con- tained in tobacco smoke have a local carcinogenic effect. A massive contact between the inhaled noxious substance and the bronchial mucosa as the target tissue is necessary. Based on all the available data, that is the pattern that we must assume exists for the smoker who inhales. AF: And what does that mean for the passive smokert Schmxhl: First of all. depending an the size of the room. its ventila- tion, and the distance from the smoker, the substances in question are greatly diluted for the passive smoker compared to active inhalation. Second, in pas- sive smoking there is not the direct route from the mouth to the bronchial tree; rather. the passively inhaled smoke passes through the nasal filter, so that a further dilution of the hazardous substances occurs. The result of these two factors is a dilution that certainly involves several orders of mag- 3

nitude. Nov if the major epidemiological studies of active smoking are considered from this aspect, there is a truly significant increase in the risk of bron- chial carcinoma for the actively inhaling smoker only if he smokes at least five to ten cigarettes a day. Just consider how mtch a passive smoker would have to inhale in order to bring the equivalent of five actively inhaled cigarettes into his lungs; the only possible conclusion is that such extreme exposure levels are not found in daily life. Yp: Once again, epidemiological considerations have slipped into this line of reasoning. Can the subject also be discussed from a more mechanical point of view? SchmYhl: The bronchial carcinoma of the smoker is a squamous cell carci- . noma. This type of carcinoma never arises from a normal mucous membrane. Rather, there are quite characteristic preliminary stages. The process begins with a paralysis and the subsequent destruction of the ciliary apparatus which is responsible for the self-cleaning of the bronchus. In the next stage, this damaged mucous membrane is transformed from cylindrical epithelium to squamous epithelium. Only then does the tumor begin to grow. This pattern has been described experimentally and clinically by a great many pathologists. 9owever. I do not know of a single study in which - changes like this, which are inevitable in the bronchial carcinoma of smokers, have been identified in passive smokers. AP: But there is indeed a Japanese study that has demonstrated an increased risk of cancer for vives who are passive smokers. N Schmahl: Discuss this study with critical epidemiologists, and you'll 0 see that in the final analysis, it has proved nothing at all. Do a little N r 4 (0 N I

simple arithmetic with me. based on a realistic 24-hour day. The husband who smokes spends eight hours sleeping and nine to ten hours at work or commuting. That leaves at best a period of six to seven hours in which the wife is subjected to passive smoking, and that only if the husband who smokes is a real homebody. If this relatively short period is going to significantly increase the risk of bronchial cancer for the wife, the tobacco smoke would have to contain an enormously potent carcinogen, and this has been proven not to be the case. IP: In your opinion, is there a justification for no-smoking regulations that are intended to protect nonsmokers from passive smoking? Schmahl: Prohibitions are political decisions. ihere is no scientific justification for such prohibitions as far as the risk of lung cancer due to passive smoking is concerned. I believe that the nonsmoker has a certain right not to be bothered by smokers. But the increased risk of lung cancer is not a sound link in the line of reasoning, and thus is not to be taken seriously. If health politicians want to pass prohibitions, that's their business -- but they cannot cite a definite risk of cancer connected with the matter of passive smoking as we are discussing it. AP: Hov great is the risk that a smoker will develop a bronchial carci- noma within a particular time? Schm8hl: 'Lung cancer' isn't a single disease entity;-rather, there are four different types. It is probably undisputed that squamous cell carcinoma. which constitutes ca. 70Z of all lung cancers, occurs practically only in amokers. However, it cannot be said that every smoker will get lung cancer. It can only be said that the statistical probability, compared with the proba- bility for a nonsmoker, increases with the number of cigarettes smoked daily 5 N O N N ~ CG N C9 m m

for a particular period, and that for heavy smokers, for example, those who have smoked 30 or more cigarettes for several decades, the probability can be 30 to 60 times as high as for nonsmokers. eP: In addition to the number of cigarettes smoked, does their strength enter into the calculation of risk? Schmahl: The smoker's addiction is an addiction to nicotine -- but the cancer is caused by the condensate. In the early research groups, we were among the first to call for 'less harmful cigarettes', although it must be recognized that there can be no such thing as a completely harmless cigarette. But the cigarettes can be made less harmful, and in fact this has been done. The risk of bronchial carcinoma is as much as 30S.Lower for smokers of cigar- ettes that are lower in condensates than for smokers of high-condensate cigar- ettes. The lung carcinomas that we are now seeing clinically, given a latency period of 2.5 to 4 decades, were caused by smoking the cigarettes that were on the market 30 years ago. It is interesting that in many countries, the frequency of bronchial carcinoma is declining. This development is probably attributable to the cigarettes with a Lower content of condensates. Given the ! long latency period for lung cancer, the decreasing number of smokers cannot yet have had any effect on the statistics for morbidity or mortality. i1F: The toxicologist Semmer, professor emeritus of Tubingen, maintains that sidestream smoke has a significantly higher carcinogenic potency than actively inhaled smoke. How can this be explained7 SchmYhl: For me personally -- and here I find myself in very good com- pany -- the reasoning of my otherwise highly esteemed colleague gemmer is at all convincing. And I strongly criticize the fact that he presents no 6

established data, so that his arguments remain pure speculation. Of course, that is his perfect right, but it doesn't advance the scientific discussion. AP: We've been discussing epidemiology and tozicology; now let's turn to preventive medicine. Is the protection of nonsmokers a relevant subject in this field? Schmahl: If we are serious about preventive medicine, there are a great many problems that are much more urgently in need of solutions. If anything at all is to be achieved in the area of smoking and nonsmoking, it's not a question of prohibitions, but rather a matter of education. Of course, physicians nowadays must be quite conscious of the importance of preventive medicine. govever, in order to maintain their credibility, they should only call for measures that can be demonstrated with facts and figures. For passive smoking, unlike actively inhaled smoke, there is no such demon- strable risk as far as lung cancer is concerned. :1F: Thank you for this discussion. [Takeouts:] (p. 3] The discussion of a causal relationship between passive smoking and bron- chial carcinoma has by no means arrived at the conclusion that an elevated . risk may be assumed to exist in this respect. [p• 6] It is probably undisputed that squamous cell carcinoma, which constitutes ca. 70Z of all lung cancers, occurs practically only in smokers. 7 N O N N CA GD N ~ O

There is no doubt that smoking is harmful to the smoker. There is no such thing as a completely harmless cigarette. -- Schmahl In the early research groups, we were among the first to call for •less harmful cigarettes.• A risk of bronchial cancer exists essentially for the smoker who inhales. that is. who smokes through the lungs. For a smoker who only puffs, the risk is approximately comparable to that for a nonsmoker. (p• 6] In my opinion,  gross imbalance develops when the discussion unfortu- nately turns from the risks of active smoking to g N those of passive smoking. Q N N N ~ N T ~ N

Prohibitions are political decisions. There is no scientific justifica- tion for such prohibitions as far as the risk of lung cancer due to passive smoking is concerned. 9 N O N N Lj1 N ~ ~ N