Document wgVJY7776OZb3m6RxZj3ak8gD

FILE NAME: Smoking (SMOK) DATE: 1942 DOC#: SMOK033 DOCUMENT DESCRIPTION: Book Excerpt - Cancers of the Respiratory System OCCUPATIONAL TUMORS AND ALLIED DISEASES By W. C HUEPER, M.D. ASSISTANT DIRECTOR AND PRINCIPAL PATHOLOGIST WARNER INSTITUTE FOR THERAPEUTIC RESEARCH N EW YORK CITY 1942 CHARLES C THOMAS PUBLISHER SPRINGFIELD ILLINO IS BALTIMORE M ARYLAND - CANCERS OF TH E RESPIRATO RY SYSTEM 403 They occur, moreover, in the peribronchial lymph nodes, within the walls of the sinuses, and embedded in fibrous areas. In the alveoli they are surrounded by phagocytic, mononuclear cells and foreign body giant cells massed espe cially around the larger bodies. T he interstitial tissue shows a diffuse fibrous thickening and scarring. The asbestosis is, thus, an indurative, interstitial, diffuse fibrosis of the lung increasing in degree from the apex to the base. Asbestosis and Carcinoma of the Lung. It is only in very recent years that serious consideration has been given to the possibility of a cancerigenic action of asbestosis upon the lungs. In an analysis of 18,280 death certificates for cancer of the lung and larynx in males from England and W ales from 19 2 1 to 1932, Kennaway and Kennaway did not find any cases of lung cancer in asbestos workers. Since 19 35, an appreciable number of cases of asbestosis associated with carcinoma of the lung, have been reported from England, Germany, and the United States (Lynch and Smith; Lynch; Gloyne; W ood; Horning; Nordmann; and Egbert and Geiger). The incidence of lung cancer among workers in whom an asbestosis was found at autopsy is relatively high, ranging from 17 per cent (Nordmann: 2 out of 17 cases) to 20 per cent (W ood: 2 or possibly 3 out of 12 cases). T eleky noted that there exists a minimum of 39 and a maximum of 78 autopsies in fatalities from asbestosis, the records not being clear in this respect. T eleky only knows of 6 cases of pulmonary cancer with asbestosis, and feels that this ratio is high in comparison to the number of necropsies. Koelsch mentioned the occurrence of 12 cases [Lynch ( 3 ) ; Egbert and Geiger ( 1 ) ; Gloyne ( 2 ) ; Dominici ( 2 ) ; Baader ( 1 ) ; Nordmann ( 2 ) ; W ood ( 3 ) ; and Horning ( 1 ) ] . Lynch and Smith found among 35 autopsies with asbestosis 2 cases of pulmonary malignancy (six per cent), whereas there was an incidence of only 0.3 per cent of this type of neoplasia among approximately 2,300 autopsies of the general population. The period of occupational exposure to asbestos dust ranged for five cases from 7 to 21 years, but in an additional case only a year and a half. In several instances the lung tumor became manifest several years ( 1 0 to 12 ) after cessation of the work in asbestos. Fifteen to twenty-one years elapsed (average, 18 years) between the first exposure to asbestos and the death from asbestosis with carcinoma of the lung. T he age at death depended upon the age of the in dividual at the time of the first exposure. The workers dying in the more advanced age groups entered an occupation with an asbestos hazard later in life, while those who died at an early age started to work in asbestos plants when still young. There was no evidence of a so-called old age predisposition, as two of these cases died at the age of 35 years and a third was 4 1 years old. T he majority of neoplasms were cornified squamous-cell carcinomas. Only one case was an adenocarcinoma, and a second was an anaplastic, round-cell carcinoma. T he latest case reported by Lynch and Smith showed squamous cellular and glandular carcinomatous structures. This numerical distribution between the different histologic types of carcinomas varies distinctly from 404 OCCUPATIONAL TUMORS AND ALLIED DISEASES that usually observed (Nordmann), but agrees with the shift toward a more frequent occurrence of the cancroids noted in recent years by Probst in pul monary malignancies of unknown genesis. A multicentric development of malignant growths in asbestos lungs was found by Nordmann and Gloyne, and it is considered by Nordmann as a characteristic feature of this type of lung cancer. A multifocal sprouting of squamous cells lining the bronchial walls was seen by Nordmann, who regards these changes as precancerous in nature. A diffuse, proliferative thickening of the bronchial epithelium was recorded by Gloyne, who believed that this constituted a continuous pro longation of epithelial growth from some unknown starting point rather than a series of isolated proliferative units. These epithelial prolongations were hollow in places, showing a degenerating layer of cells surrounding a central empty space, and, in turn, being enveloped by rings of keratinized squamous cells. The carcinomas of three cases were very small [Gloyne (2)5 and Nordmann ( 1 ) ], and had not produced any metastases. For this reason two of these cases (Gloyne) represented coincidental observations made during the post-mortem examination. T he other cases were large tumors with ex tensive metastatic deposits in remote organs. An evaluation of the evidence presented reveals certain features connected with these cases, which are suggestive of an occupational causation. There is an incidence of lung cancer in asbestosis of the lung which is definitely excessive. The relatively small number of necropsies on which this conclusion is based represents an urgent indication for more extensive post-mortem examinations in cases of asbestosis j especially considering that pulmonary malignancies seen in previously reported cases were, in several instances, very small and were coincidental observations. A second point favoring an in dustrial origin is the young age of an appreciable portion of the cases thus far recorded, and the relationship existing between the time of exposure to asbestos dust and the manifestation of the neoplasms throughout the entire series. T he third factor consists in the shift of the histological types observed in the direction of a predominance of cancroids, and in the multicentric de velopment of two (Nordmann; and Gloyne) and possibly even three (Lynch and Smith) of these pulmonary neoplasms. The existence of the cutaneous warty lesions suggests that asbestos needles embedded in epithelial tissue are apparently capable of eliciting non-inflammatory, epithelial proliferations. Nothing is known about the actual causative mechanism through which as bestosis may produce such epithelial lesions, and may transform them subse quently into malignant growths. The assumption of a chronic irritation of nonspecific nature or of specific silicotic character, such as proposed by Lynch, is scarcely acceptable and satisfactory in view of the negative evidence available in this respect. One of the cases reported by Nordmann in association with Horning showed symptoms of a marked and generalized, allergic disposi tion (bronchial asthma, and hematic eosinophilia), which may have played a CANCERS OF TH E RESPIRATO RY SYSTEM 405 contributory role in the development of the neoplastic response. Asbestos bodies contain a considerable amount of iron, and there exists some evidence that points to a possible causative interrelation of pulmonary siderosis and carcinoma. The relatively small number of asbestosis carcinomas o the lung reported does not disprove an occupational origin of this condition. Previous experience with other industrial neoplasms (lung cancer of the Joachimsthal miners^ and lung cancer of the chromate workers) has shown that such iso lated cases may represent the first warning of a subsequent appearance of large numbers of similar tumors of undeniable occupational derivation. Medico-Legal and Social Aspects. Asbestosis carcinoma of the lung is not included in any group of occupational tumors recognized by any country. T he evidence presented is sufficiently serious, and the number of persons exposed to the suspected causative agent large enough to indicate a thorough and extensive clinical, statistical, and experimental investigation of the incidence and causative interrelation of asbestosis and pulmonary carcinoma. In view of the fact that several of the states with many large asbestos plants do not include asbestosis among compensatory occupational diseases, this study is even more urgent. Such a condition militates against an effective hygienic control of an important industrial hazard, and impedes the collection of pertinent and essential information in regard to the incidence, nature, and potentialities of an occupational disease growing steadily in general sig nificance. W orkers dying from asbestosis should be subjected to a post-mortem examination including a histological study of the pulmonary lesions, as multiple neoplastic manifestations in asbestosis may be mistaken for tubercu losis (Lynch). Sanitary Measures. The following measures may be taken to eliminate or reduce the existing hazard caused by the inhalation of asbestos dust: humidi fication of the asbestos matter and the air to decrease the production of dust; introduction of a closed production system, wherever possible} establishment of an extensive and efficient exhaust ventilation} frequent cleaning of the workrooms to remove the accumulated dust; prevention of air currents caused by moving machinery parts; construction of rooms, machinery, and pipelines offering little opportunity for deposition and accumulation of dust; separa tion of operations in which the production of dust can be eliminated entirely from those in which this is not possible; wearing of respirators by workers engaged in dusty operations; and mechanization of operations under elimina tion of human labor to reduce the number of workers exposed. T he dust hazard is most pronounced in store rooms for raw material, in rooms in which the raw fibers are handled, and in spinning, weaving, mixing, and filling rooms. Siderosis Occupational siderosis of the lung is of the black type, which is caused 426 OCCUPATIONAL TUMORS AND ALLIED DISEASES various sources. Kennaway pointed out that there had been a pollution of air with soot for a long time before the increase in the incidence of pulmonary malignancy was noted. The rarity of this type of neoplasm among chimney sweeps (one case among 65 cases of chimney sweep cancer (1920 -19 23)) was cited by Kennaway in confirmation of his contention. Fischer-Wasels mentioned that the tar and pitch workers who inhale considerable amounts of tar dust suffer rarely from lung cancer in spite of the fact that they ' develop cutaneous carcinomas from their occupational exposure to this carcinogenic agent. A similar statement was made by Barnewitz and Behring in regard to the low incidence of lung carcinoma among the pitch and tar workers in the R uhr district. Habitual Exposure to Tarry Substances. T h e tobacco smoking habit pro vides an additional source through which tarry substances of known car cinogenic quality may enter the respiratory system. It has been suggested by investigators that this rapidly spreading habit, especially in regard to cigarettes, may have some relation to the increase and production of pulmo nary malignancy (Bogen and Loom is; Schurch and Winterstein; Hruby and Sweany; R offo; M cN ally; Lickint; Brockbank; M u ller; and others). It is contended that not only persons who smoke, but also those who inhale tobacco smoke because of environmental reasons over prolonged periods (waiters, housewives, etc.) show an excessive liability to lung carcinoma (Editorial, J.A .M .A .). The amount of tarry substances introduced into the respiratory tract by a heavy smoker is, in the opinion of Lehmann, much greater than that inhaled by an automobilist travelling on a tarred road. The occurrence of pulmonary malignancy in two heavy smokers was reported by Campbell. Similar observations on a large series of lung cancers (96) were reported by M uller. Lickint asserted that carcinomas of organs which are situated in the so-called smoke-tract (lips, oral cavity, larynx, trachea, bronchi, lung) are found more frequently in smokers than in non-smokers. This investigator sees in the exposure- to tobacco tar the reason for the numerical discrepancy in the incidence of lung cancer among the two sexes, and for the more rapid increase of this type of cancer among men than among women. It may be added that this argument is open to question, in view of the increase of this habit during the last two decades among the female sex. Jackson and Jackson presented in 19 4 1 statistical data indicating a small but progressive yearly increase in the incidence of laryngeal cancer probably caused by smoking. The proportion of men to women with this lesion was 1 0 :1 , and 95 per cent of the men were smokers. Occupational Atmospheric Mineral Oil. There exists also some evidence incriminating the respiratory contact with carcinogenic oils for the develop ment of malignant tumors of the respiratory organs. A relatively high ratio of laryngeal cancer was found by Kennaway and Kennaway in mulespinners, who, during their work, inhale a mist of a carcinogenic shale oil used