Risk of lung cancer by histology among immigrants to Sweden

BackgroundWe wanted to define lung cancer incidence rates by histological subtype among immigrants in Sweden to explore the effect of new environments on the incidence of lung cancer by histological subtype in different ethnic populations.MethodsThe nationwide Swedish Family-Cancer Database w used to calculate age-standardized incidence rates (ASR) (per 100,000) and standardized incidence ratios (SIRs). The patient series covered 19,255 male and 14,601 female Swedes, and 3236 male and 1751 female immigrants.ResultsBy time since immigration, Former Yugoslavian (ASR = 46.4) and Asian Arab (38.8) men, and Danish (23.3), Norwegian (19.5) and Finnish (14.5) women had the highest rates for lung cancer, while the lowest rate was seen among Asian Arab women (5.8). The highest adenocarcinoma rates were seen among South European men (11.5), and Danish (7.4) and Norwegian (6.9) women, while squamous cell (SCC) and small cell carcinomas rates were the highest among former Yugoslavian (16.0) and Baltic (8.8) men, respectively. Former Yugoslavian men (2.6) had the highest rate for large cell carcinoma. Compared to Swedes, former Yugoslavian men had the highest significant risk for SCC (SIR = 3.62), small cell (3.14) and large cell (4.21) carcinomas, whereas the highest adenocarcinoma risk was seen among Asian Arabs (2.35). Danish women had the highest risks for SCC (1.91) and small cell carcinoma (2.56).ConclusionThe ethnic-specific lung cancer rates by histology followed the rates in the countries of origin. Our findings may suggest that preservation of smoking habits in the host country is linked to the ethnic diversity of lung cancer incidence by histology.