Lung cancer in scleroderma: results from an Italian rheumatologic center and review of the literature

The association between systemic sclerosis (SSc) and cancer was widely described, particularly with breast and lung carcinoma; while, data regarding possible associations between cancer and SSc features are still scarce. We retrospectively evaluated the prevalence of lung cancer in our SSc patient cohort (318 SSc patients, 31 M and 287 F, age 51.5±14.5SD years, disease duration 10.3±6.5SD years) and clinico-serological factors potentially associated to the development of this malignancy. A review of the world literature about this topic was also done. We found that lung cancer complicated 16/318 (5%) SSc patients; namely 11/287 females (4%) and 5/31 males (16.1%). Median age of SSc patients with lung cancer was 54 (range 38-72) years for female patients, and 63 (range 40-73) for males; 13/16 patients died because of the neoplasia. Considering the incidence of lung carcinoma in sex/age-matched general population of the same geographical area, the percentages of lung cancer in our SSc series are about 2.5 and >5 times higher for male and female patients, respectively. The presence of lung cancer significantly correlated with male sex (p=0.011), presence of anti-Scl70 antibodies (p=0.0007), cyclophosphamide therapy (p=0.0001), forced vital capacity (FVC) <75% (p=0.0001), and lung fibrosis (p=0.0127); moreover patients with cancer have a significantly lower age at the diagnosis of SSc (p=0.009) and longer disease duration (p=0.0175). The logistic regression analysis confirmed a significant association with the anti-Scl70 antibodies (OR 6.4, 95%IC 1.7-24.1; p=0.006) and the reduction of FVC (OR 6.7, 95%IC 2.2-20.7; p=0.001) only. Overall, the prevalence of lung cancer in the subset of SSc patients with anti-Scl70 antibodies was 12/105 (11.4%), 9/40 (22.5%) in patients with FVC% reduction, and 7/22 (31.8%) in patients with both. In literature, the median prevalence of lung cancer in SSc series was 2.4% (range 0-4.2%); even if sporadic, associations with lung involvement or antiScl70 autoantibodies were raised, according to our findings. Our study confirmed the higher frequency of lung cancer among SSc patients compared to general population, particularly within patients' subset with serum anti-Scl70 antibodies and lung involvement.