A Brief Discussion of the Etiology of Bronchiogenic Carcinoma

¹ The Department of Surgery, Washington University School of Medicine and Barnes Hospital, St. Louis, Missouri.

(1) A very remarkable increase in the incidence of bronchiogenic carcinoma has occurred in the last 25 years. From having been a curiosity in 1930, by 1950 it was so common that it had become the most frequent cancer in the male sex.

(2) No less than 12 statistical studies have shown a definite etiologic relationship between the disease and excessive cigarette smoking. Of equal importance, perhaps, is the fact that no careful study has been published which fails to show that relationship.

(3) The statistical evidence has been strongly supported by the experimental production of epidermoid carcinoma in the skin of CAF₁ mice by painting the skin with tar obtained from cigarette smoke. The incidence of cancer production was 44.4 per cent in 81 tarred mice.

(4) A mistake is commonly made in thinking that bronchiogenic carcinoma is a single disease. Actually there seem to be at least three separate varieties with different etiologies.