OCCUPATIONAL NEOPLASTIC DISEASE CUSHMAN D. HAAGENSEN, M.D. (From the Memorial Hospital, New York City) The extensive investigations of occupational cancer, with the resultant important contributions to the literature of the subject from England and Germany during recent years, have stimulated interest in this field of cancer research. Since the incidence of the various types of occupational cancer apparently differs greatly in different countries, and the statistics on this subject for the United States are incomplete both as regards cancer morbidity and cancer mortality, we have proposed to survey the cancer morbidity data of the Memorial Hospital, which represents, we believe, the largest group of neoplastic diseases in an industrial community in the United States. In this study we shall discuss: (1) the occupational distribution of certain types of neoplastic disease; (2) their occupational inci­ dence; (3) the anatomic distribution of the cancers in the occupa­ tional groups; (4) the average ages at which the tumors occurred in the different occupational groups. 1. THE OCCUPATIONAL DISTRIBUTION OF NEOPLASTIC DISEASE The importance, in the etiology of cancer, of various agents which produce prolonged or chronic irritation is now generally recognized. Occupational cancer produced by tar, creosote, anthracene, pitch, soot, shale oil, petroleum, arsenic, aniline dyes, radium, and roentgen rays has been observed clinically. It has been produced experimentally in animals by these and other agents. In man the association of chronic irritation due to noxious occupa­ tional agents with cancer has naturally been most often observed on the surfaces of the body-on the skin and mucocutaneous surfaces. With the exception of cancer of the bladder in aniline dye workers and cancer of the lung in the Schneeberg miners, no relationship has been shown to exist between occupation and cancer of any of the internal organs. Young and Russell, for example, found that cancer of the tongue, esophagus, and stomach occurred with somewhat less than the normally expected frequency among 641 642 CUSHMAN D. HAAGENSEN cotton-spinning employees, who are subject to the most prevalent type of occupational cancer-mule spinners' cancer of the scrotum. This inquiry has, therefore, been limited to an investigation of the occupation in cancers of the skin, mucocutaneous surfaces, bladder, and lungs. During the period from January 1917 to January 1, 1930, there were accepted at Memorial Hospital 21,510 patients with neoplastic diseases. Of these, 2,914 had malignant tumors of the skin, 678 of the lip, 104 of the penis, 11 of the scrotum, and 125 of the vulva. There were 453 carcinomas and 66 papillomas of the urinary bladder and 108 carcinomas of the lung. Among these 4,459 histories the patient's occupation was noted in 2,684, or 60 per cent. Coal Coal, from which tars and other hydrocarbons are derived, is itself apparently innocuous, although, as Ross remarks, it is hard and gritty and may well cause mechanical injury of the skin TABLE I Cancer of the Skin and Mucocutaneous Surfaces in Occupational Groups (Male) Particularly Exposed to Coal Occupational Group Type of Lesion Ear Eyelid Nose Cheek Lip Neck Hand Penis Total ---- --- - ------ Coal shoveller Squamous carcinoma 1 1 --------- ------ Coal bargeman Squamous carcinoma 1 1 ------- - ---~ -- Fireman Squamous carcinoma 3 1 1 5 (unspecified) --- --- - ------ Basal-cell carcinoma 1 1 2 .---- --- - ------ * Epithelioma..... 1 3 3 7 TOTAL.... .. , ... ..... .. ... ......... 16 .. * Under epithelioma are included all cancers in which the type was not verified by biopsy. amounting almost to laceration. Coal miners, firemen, and many other workers come into intimate contact with it; yet Young and Russell found no significant 1 excess of cutaneous cancer among coal miners, according to English mortality statistics. The Memorial Hospital records are remarkable for the small number of cases of cancer of the skin and mucocutaneous surfaces with a history of exposure to coal and coal dust. These cases are listed in Table 1. 1 The word "significant" is used throughout this study in thc narrow statistical sense of significance with respect t.o errors of random sampling. OCCUPATIONAL NEOPLASTIC DISEASE 643 Tar and Pitch Coal tar may be described as concentrated coal. It is the residue after the first stage in the distillation of coal. Its composi­ tion is dependent upon the kind of coal from which it is derived and also upon the method of carbonization employed. Gas works and coke ovens produce most of it. Naphthalene, phenol, pyri­ dine, creosote oil, anthracene, and pitch are successive fractions obtained in the distillation of tar. Of all these products, pitch is probably the most highly carcinogenic. Woglom has made the most comprehensive study of the vast amount of experimental work which has been done with tar and its related substances. In 1875 Volkmann described tar cancer occurring among the lignite tar workers of Saxony. Ullmann has reported 10 cases of tar cancer which developed among 2,500 employees in Prussian briquette factories. There have been a considerable number of isolated case reports. British mortality statistics, however, have furnished the most extensive information on the subject. Indeed, British statistics have confirmed a great part of our clinical knowl­ edge of occupational cancer. From this source Henry lists 439 cases reported as due to tar between the years 1920 and 1928. The occupations in this group were: Patent fuel manufacture (briquette making). .. 183 Tar distilling . 118 Coal gas manufacture . 65 Pitch loading (wharves, etc.) . 22 Coke ovens . 8 Brick, tile, and pipe manufacturing . 6 Producer gas manufacture. ... 6 Cable manufacturing . 6 Creosoting timber _.. ,.,. 5 Anthracene manufacture _ 4 Net fixing and barge repairing. ................. 5 Felt proofing . 2 Brattice cloth, asphalt trough, electric brush, insulator, and bitumastic paint manufacturing, sailmaking, cable handling, road mending, and creosoting molds in steel works, each . 1 This list illustrates the wide variety of uses to which tar and tar products are put in modern industry and the possibilities of their carcinogenic importance. The increasing use of tar in road­ making more and more exposes the whole population. Because of the lack of occupational mortality statistics in the United States, it is difficult to estimate the frequency of tar cancer in this country. H. B. Wood, in an investigation in Pennsylvania, found a few warty 644 CUSHMAN D. HAAGENSEN conditions but no cancer among 88 workmen who handled tar in six gas works, six coke by-product plants, five briquette works, and in the largest tar products plant. The Philadelphia Gas Company, employing 750 men, reported no cases of cancer. No carcinoma was found among workmen creosoting wood. Heller has recently investigated tar distillation plants, battery manufacturing plants using pitch, wood-preserving plants, and briquette-manufacturing works. No cancer was found among the briquette workers because, Heller believes, liquid petroleum asphalt is used as a binder and because the workmen do not come into contact with it. He collected 37 cases of probable tar cancer and found that gas-works tar and pitch were responsible for 70.2 per cent of the cases. He concludes that gas-works pitch is much more highly carcinogenic than coke-oven tar and pitch. There are definite precancerous dermatoses occurring among workers with tar and pitch. Volkmann describes small red nodules corresponding to the openings of the sebaceous glands, forming on the skin of the head, arms, hands, and scrotum of workers with tar. After the acute phase the red nodules diminish, leaving a black point or comedo. The skin between the glands becomes thickened, dry, and stiff. Small warts and horns of epidermis and flat, brown scales and crusts form. Legge describes the pitch warts common to briquette workers. They begin as small nodules and almost im­ mediately begin to break down, forming an ulcer covered by a crust which gives the characteristic appearance of the so-called wart. The underlying ulcer almost always heals, leaving a small scar when the crust has fallen off. The cases of cancer of the skin and mucocutaneous surfaces with an occupational history of exposure to tar from the Memorial Hospital data are briefly as follows: 1. J. H. M., a roofer, aged sixty: Epithelioma of the skin of the cheek near the angle of the mouth. 2. A. S., a roofer, aged thirty-six: Epithelioma of the nose. 3. E. N., a roofer, aged sixty: Epithelioma of the lip. 4. J. B., a roofer, aged seventy-two: Epithelioma of the nose. 5. T. M., a painter and roofer, aged seventy-four, who remembered having been spattered with tar many times, and whose face had also been burned with powder: Multiple epithelioma of the face and keratoses of face and hands. 6. J. F., a tar roofer who had worked with tar for thirty-three years: Keratoses of the skin of the face and a squamous carcinoma of the right ear (Figs. 1 and 2). OCCUPATIONAL NEOPLASTIC DISEASE 645 7. N. P., a roofer, aged seventy: Epithelioma of the upper lip. 8. M. M., aged sixty-nine, a road mender who had worked with tar for twenty-two years: Basal-cell epithelioma of the tip of the nose. 9. D. F., a road mender who had repaired asphalt roads for seven years: Epithelioma of the hand. 10. J. M., a workman who had handled barrels of tar, frequently spilling it on himself: Epithelioma of the skin of the cheek. FIGs. 1 AND 2. SQUAMOUS CARCINOMA OF THE EAR IN A ROOFER (J. F.) WHO HAD WORKED FOR THIRTY-THREE YEARS WITH TAR 11. E. G., aged seventy-two, who had worked with tar occasionally, was a painter in winter and worked on the beach in summer: Epidermoid carcinoma of the nose. 12. H. P., a telegraph operator, who had burned the dorsum of his left hand with hot tar: Epithelioma in the burned area.