Risk of Lung Cancer by Histologic Type among Smokers in Miyagi Prefecture

Smoking habits of the 827 lung cancer patients aged 40 yearsor over who were treated in the Sendai Kosei Hospital from 1977–82were compared with those in the general population of a non-metropolitandistrict in northern Japan, which we recently surveyed by mailquestionnaire. The relative risks of lung cancer by histologictype adjusted by age and area of residence were as follows:1.9 for adenocarcinoma, 4.3 for squamous cell carcinoma, 3.9for small cell carcinoma and 3.4 for large cell carcinoma inmen, and 2.9, 6.4, 4.5 and 4.0 for these histologic types, respectively,in women. These elevated risks were all statistically significant(p < 0.05). These findings suggest that smoking habits shouldbe carefully considered when studying the etiology of any celltype of lung cancer, even adenocarcinoma, which often has beenthought to be unrelated to smoking habits.