Primary tumors of the lung are surprisingly frequent. All newer writers agree that pulmonary cancer is increasing. The increase is not only apparent but real.
The frequency of pulmonary tumors in newer clinical statistics might be explained by greater diagnostic accuracy; however, a similar increase is noted in necropsy statistics, and this cannot be accounted for otherwise than by matters of fact. The cause of the increase is no clearer than is the cause of cancer. Perhaps postinfluenzal changes have something to do with it.
In 1886, Fuchs calculated that primary cancer of the lung formed 0.06 per cent, of 12,307 Munich necropsies. Ewing (1922) states that, in deaths from cancer, the lung was found to be the seat of the primary tumor in about 1 per cent.; other statistics place the lung as being affected in from 1 to 2 per cent.; Berlin statistics give 3.4 per cent. (Karrenstein,