Frequency of different histologic types of bronchogenic carcinoma as related to radiation exposure

Epidermoid, small cell undifferentiated, and adenomatous types of bronchogenic carcinoma were all shown to be increased among uranium miners. This was done by use of calculations of expected numbers for each of the major histologic types. The predominance of the small cell undifferentiated histologic types, however, was so great that it appeared to be the only type whose frequency was elevated in earlier, relative distribution studies. The same three histologic types have been shown to be elevated among cigarette smokers, but with different relative frequencies. These findings are consistent with Kreyberg's hypothesis that small cell undifferentiated and epidermoid carcinomas of the lung are closely related, and are the principal types whose frequency is affected by inhaled carcinogens, even though adenocarcinomas are also increased to some extent.