Histologic type of lung cancer in relation to smoking habits, year of diagnosis and sites of metastases.

A study was made of histologic type of lung cancer in relation to smoking habit, year of diagnosis, age and sites of metastasis. It comprised 662 autopsies of men during the period from 1955 to 1972. As classified by the WHO system, 35.2 percent were epidermoid carcinoma, 24.6 percent were small cell carcinoma, 25.2 percent were adenocarcinoma and 14.2 percent were large cell undifferentiated carcinoma. The six non-smokers of the series were all found to be in class 3, adenocarcinoma. No clearcut and consistent relationships were observed. Although there was a steady decrease in the incidence of small cell carcinoma during this time period, this observation did not prove to be statistically significant. Small cell carcinomas increased with amount of smoking but not for all age groups. Adenocarcinomas decreased with advancing age but not in all smoking groups. Metastases were found in 96.3 percent of the cases and the sites most frequently involved were regional lymph nodes, liver, brain, distant lymph nodes, adrenals and bone. Small cell carcinomas showed the greatest percentage of involvement for those major sites and for the same sites, epidermoid carcinoma showed the lowest percentage.

Presence of asbestos bodies in organs other than the lung.

This study was designed to test the hypothesis that subjects with many asbestos bodies in their lungs at autopsy would also have asbestos bodies in various other organs. The subjects included 19 cases with diagnosis of asbestosis at death (two of these had mesothelioma, five had lung cancer) and 18 with pleural plaques but not asbestosis. Occupational histories were obtained from relatives. In subjects occupationally exposed to asbestos, large numbers of asbestos bodies were found in the lungs, and in most of these, asbestos bodies were found in many of the other organs examined. In the 18 cases with only pleural plaques found at autopsy, considerably fewer asbestos bodies were found in the lungs. The number of other organs with one or more asbestos bodies ranged from 32 percent to 62 percent of the sites examined. The findings seem to confirm the hypothesis of the study.

Scar cancer of the lung: increase over a 21 year period.

In a review of 1,186 cases of lung cancer found amoung 7,629 autopsied cases over a 21 year period a total of 82 peripheral cancers related to scars were found, constituting 1% of the autopsied cases and 7% of the lung tumors. 15% of all lung tumors were peripheral (vs. bronchogenic) and the percentage rose from less than 7 in the time period of 1955 to 1960 to a little more than 23 in the 1970 to 1976 time period. 45% of all peripheral lung cancers originated in a scar. Less than 2% of all lung cancers were found associated with scars in the 1955 through 1959 time period. This increased to nearly 16% in the 1970 through 1975 time period. 72% of the scar cancers were adenocarcinomas and 18% were of squamous cell type. The rest were large cell undifferentiated carcinomas and none was oat cell or small cell type. Over three-quarters of these scar cancers were found in the upper lobes and more than half were related to infarcts. Less than a quarter were related to tuberculosis scars. No relationship was found between smoking habits and scar cancer.

Morphologic alterations induced by short-term cigarette smoking.

Pulmonary fibrosis and emphysema were produced in beagle dogs by their direct inhalation of cigarette smoke over a relatively short period of time (2-7 cigarettes daily for 2-4 months). One dog was sacrificed after having smoked 172 cigarettes, one after 282 cigarettes, and the others after 480 and 534 cigarettes, respectively. Examination of the lungs by scanning and transmission electron microscopy showed a range of response from the presence of numerous smoker's macrophages to extensive alterations, including destruction and enlargement of alveolar ducts and varying degrees of enlargement of alveolar spaces. Interalveolar pores were enlarged, and marked fenestration leading to destruction of the alveolar walls became apparent. These features were accompanied by interstitial fibrosis of the interalveolar septa. Light- and electron-microscopic examination showed no evidence of bronchitis and/or bronchiolitis or of physical obstruction to the terminal airways in the early development of fibrosis and emphysema.

A comparison of World Health Organization (WHO) classification of lung tumors by light and electron microscopy.

Forty-nine cases of lung tumor were initially classified according to the World Health Organization (WHO) system by light microscopy. Additional study by electron microscopy using only a minimum of ultrastructural features as criteria for each type made more precise classification of some of the poorly differentiated or undifferentiated tumors possible. Most significant was the finding of evidence of a second tumor type in nine of the 35 tumors previously classified as moderately to well differentiated thus reclassifying them as mixed tumors. Sixteen of the 49 tumors were reclassified and a more precise classification was made in five others. Only two cases of undifferentiated small cell tumors were available and no unequivocal neurosecretory granules could be found in either. Correlation of the more precise typing of lung tumors by electron microscopy with the clinical data and modes of therapy will provide necessary information for determining the usefulness of the WHO classification.

Histologic type of lung cancer and asbestos exposure.

The histologic types of lung cancer in 855 patients (747 men and 107 women) from three hospitals and one international study of insulation workers were evaluated. Of these, 196 cases had asbestos exposure. About one half of the cases were diagnosed from surgical slides and one half from autopsy slides. Squamous cell carcinoma constituted the largest percentage of tumor types and was found with the same frequency in exposed and nonexposed groups. Small cell carcinoma was found in 25% of the exposed and in 15% of the nonexposed patients. Upper lung sites were involved in about two thirds of the cases with asbestos exposure and lower lobes in the other one third. There was little difference in histologic type in cases regardless of whether upper or lower lobes were involved. Cigarette smokers who smoked until their cancer diagnosis showed no difference in histologic type by amount smoked, and slight but not statistically significant differences from ex-cigarette smokers.