Significant changes in the distribution of histologic types of lung cancer in Hong Kong.

A retrospective study of 2385 Chinese patients with proven carcinoma of lung was performed. The autopsy incidence was 3.3%. Most patients presented in the seventh decade. The age distribution was 24-94 yrs with a mean age of 63 yrs. The four major histologic types (37.3% of adenocarcinoma, 33.4% of squamous cell carcinoma, 13.7% of small cell carcinoma and 14.7% of large cell carcinoma) accounted for 99.1% of the cases. Among the four, adenocarcinoma was the most common histologic type, particularly for females and there has been an increase in the incidence of adenocarcinoma in recent years. This trend has been observed and reported in many affluent countries. In Hong Kong, the frequency of adenocarcinoma among Chinese females is exceptionally high.