Lung cancer incidence rates by histologic type in high- and low-risk areas; a population-based study in Osaka, Okinawa, and Saku Nagano, Japan.

Abstract

We investigated lung cancer incidence by histologic type using the data from population-based cancer registries in high-risk (Osaka and Okinawa) and low-risk (Saku Nagano) areas. Since the proportion of cases with histologic types identified was not sufficiently high, sex- and age-specific incidence rates by histologic type were estimated assuming that the distribution of histologic types was the same across the same sex and age groups regardless of reporting status. Compared to Saku in Nagano Prefecture, the cumulative risk of lung cancer incidence rates in Osaka and Okinawa were 1.3 and 1.5 times higher for males and 1.3 and 1.2 times higher for females, respectively. When divided by histologic type, male adenocarcinoma and small cell carcinoma were 1.6-2.1 times higher in Osaka and Okinawa, while squamous cell carcinoma was 1.6 times higher only in Okinawa compared to Saku Nagano. In females, squamous cell carcinoma and small cell carcinoma were 2.5-3.3 times higher in Osaka and Okinawa compared to Saku Nagano, while adenocarcinoma was almost equal in the 3 areas. These results indicate that the pattern of incidence of lung cancer by histologic type may differ between high- and low- risk areas.