Document yrx52OOoY3pD5VorB2gDNL48X

CANCERS OF THE RESPIRATORY SYSTEM 397 Important autopsy observations made on South African gold miners, in whom silicosis is of frequent occurrence, were used in a study of the alleged causative interrelation of lung cancer in silicotic individuals (Reports of the Miner's Phthisis Medical Bureau of South Africa, 1932 and 1935). Among 3,215 autopsies performed on European males employed in the mines or members of the white population of Johannesburg (deaths in the Johannes burg General Hospital), there were 16 cases of lung cancer during a period of eight and a half and eleven years, respectively (report of 1932). The relative percentage of lung cancer of these groups was as follows: O Lri OO hH O 00 Autopsies Per cent of Lung Cancer European NonMiners 1023 Miners with out Silicosis 1109 O.54 Miners with Silicosis o-37 Similar relations were stated in the report of the year 1935 Autopsies Lung cancers Per cent 1393 13 o-93 1679 12 0.71 1438 10 0.70 These data, obtained through post-mortem examinations, indicate clearly that the presence of a silicosis does not predispose or favor the development of a pulmonary malignancy. Similar extensive studies of the question, based on the roentgenological and clinical examinations of persons exposed to dust, were reported by Vorwald and Karr, using evidence collected from the literature and their own observations. The following tables are taken from the paper of these two investigators: Incidence of Pulmonary Tumors in Clinical and Roentgenological Examinations of Individuals Exposed to Dust, as Reported in the Literature Number of Cases Non-Silicotics Silicotics Pulmonary Tumor 57,362 45A56 12,206 3(0.005%) t Incidence of Pulmonary Tumors as Revealed by Serial Chest Roentgenograms in Individuals Exposed to Dust and Examined in the Saranac Laboratory Occupation Iron Mines Foundries Cement plants Gypsum plants and mills Copper mines Silicotics Non-Silicotics Total Number Examined 7,324 6,613 823 762 65 L357 14,230 Pulmonary Tun, 3 0 0 0 0 I (0.074%) 2 (0.014%) 3 (0.019%) 0\0r\