Small Cell Lung Cancer. Methodology and Preliminary Results of the SMALL CELL Study. / Cáncer de pulmón microcítico. Metodología y resultados preliminares del estudio SMALL CELL.

INTRODUCTION: Small cell lung cancer (SCLC) is the most aggressive histologic type of lung cancer, and accounts for approximately 10%-15% of all cases. Few studies have analyzed the effect of residential radon. Our aim is to determine the risk factors of SCLC. METHODS: We designed a multicenter, hospital-based case-control study with the participation of 11 hospitals in 4 autonomous communities. RESULTS: Results of the first 113 cases have been analyzed, 63 of which included residential radon measurements. Median age at diagnosis was 63 years; 11% of cases were younger than 50 years of age; 22% were women; 57% had extended disease; and 95% were smokers or former smokers. Median residential radon concentration was 128Bq/m3. Concentrations higher than 400Bq/m3 were found in 8% of cases. The only remarkable difference by gender was the percentage of never smokers, which was higher in women compared to men (P<.001). Radon concentration was higher in patients with stageIV disease (non-significant difference) and in individuals diagnosed at 63 years of age or older (P=.032). CONCLUSIONS: A high percentage of SCLC cases are diagnosed early and there is a predominance of disseminated disease at diagnosis. Residential radon seems to play an important role on the onset of this disease, with some cases having very high indoor radon concentrations.