Lung carcinoma in the elderly population. Influence of histology on the inverse relationship of stage to age.

Unlike most cancers, lung carcinoma is more likely to be localized at the time of diagnosis in older age groups when compared to those who are middle-aged. In an attempt to explain this inverse age-stage relationship we studied 9062 histologically confirmed cases of lung carcinoma occurring from 1975 to 1984 obtained from the regional cancer registry for Kansas and western Missouri. They were analyzed according to histologic type, age, sex, and stage at diagnosis. The data suggest that the proportion of squamous cell carcinoma rises and that of adenocarcinoma and small cell undifferentiated carcinoma falls with increasing age. The proportion of staged lung carcinoma with local disease at the time of diagnosis increases with age. In males this trend occurred in all cell types except large cell undifferentiated carcinoma but was most significant for squamous cell carcinoma. Squamous cell carcinoma was the only group to show a significant trend among females. The rise in squamous cell and fall in small cell carcinoma may partially explain the increased prevalence of local stage disease with advancing age.