From an initial sample of 410 (SG) and 735 (CG) patients we were able to match 333 patients from each group. At the same follow-up time lung cancer incidence density was 1.79/100 person-years in the SG and 4.14/100 person-years in the CG (p = 0.004). The most frequent histological type was adenocarcinoma in both SG and CG (65% and 46%, respectively), followed by squamous cell carcinoma (25% and 37%, respectively). Eighty percent of lung cancers in the SG (16/20) were diagnosed in stage I, and all of CG cancers (35/35) were in stage III or IV. Mortality incidence density from lung cancer (0.08 vs. 2.48/100 person-years, p < 0.001) was lower in the SG.