Differences in epidemiological and clinical features in non-small cell lung cancer (NSCLC) in never and ever smokers

Cigarette smoking is the most important factor for lung cancer, yet it also occurs in never-smokers (NS). We assessed epidemiologic, clinical, pathological features and survival.We analyzed 504 NS NSCLC and compared with 907 smokers (S) NSCLC. Differences in epidemiological clinical features and survival between S and NS were analyzed with Studentu0027s t and Mann-Whitney U test to compare variables. Survival curves were calculated using Kaplan-Meier method.In NS NSCLC median age was 67±11 years (54% females). Most frequent histology was Adenocarcinoma (65%), followed by squamous cell (20%).There was professional exposure to carcinogens in 9%, family history of lung cancer in 5%, previous cancer diagnosis in 6% and 18% had hypertension. Stage at diagnosis was IV in 59%, with performance status (PS-ECOG) 1 in 44%. More frequent metastatic sites at presentation were lung (34%), bone (29%), and brain (10%). There were 395 deaths. Median survival was 51 months.Comparing NS-NSCLC with S-NSCLC we found more women (272 vs 85; pu003c0.001), less chronic obstructive pulmonary disease (64 vs 555; pu003c0.001), cardiac ischemic disease (19 vs 67; p:0.007), adenocarcinoma (350 vs 393; pu003c0.001), previous larynx cancer (9 vs 81; pu003c0.001); weight loss (p:0.001) and longer survival (25 vs 51months; pu003c0.001) that remained when controlled for stage and PS.In NS NSCLC female sex is more frequent, adenocarcinoma histology is more common. Comorbidity related to smoking (COPD, cardiac ischemic disease, larynx cancer) is less frequent. Survival is better across all stages. These data corroborate that NS NSCLC is a different clinical entity that has a better prognosis.