The Pulmonary Function Loss to Smoking Pack-year as an Independent Prognostic Factor in Non-small Cell Lung Cancer Patients having Smoking History.

초록

Background: Smoking is a major risk factor causing lung cancer and chronic obstructive pulmonary disease. Smoking status has been known to be an independent prognostic factor in lung cancer patients. We conducted this study to know if individual susceptibility to smoking is related to the survival in locally advanced or advanced non-small cell lung cancer (NSCLC) patients. Methods: From our prospective cohort of the lung cancer, after excluding non-smokers, we included consecutively locally advanced or advanced NSCLC patients who were completed with treatment (n=186) or treated only conservatively (n=151) in this study. All patients were performed pulmonary function testing at the time of diagnosis. We estimated individual susceptibility to smoking using a formula of (100-%predicted FEV1)/pack-year and categorized it by quartile based on the distribution among study subjects. Results: Clinical stage of the patients was IIIA in 65 (19.3%), IIIB in 120 (35.6%) and IV in 152 (45.1%). The median survival time was 13.2months (95% CI: 11.9-15.0 months) for treatment group and 4.9months (95% CI: 3.8-6.5 months) for conservative care group (P<0.001). In log-rank test survival time were significantly different according to age, sex, body weight loss (>5%), %predicted FEV1, clinical stage and individual susceptibility to smoking (P<0.005, 0.036, <0.001, 0.006, <0.001 and <0.001, respectively). The hazard ratio adjusting covariates among patients of highest quartile of susceptibility to smoking was 1.90 (95% CI: 1.49-2.38). Conclusions: Therefore we suggest that individual susceptibility to smoking may be an independent prognostic factor in locally advanced and advanced NSCLC patients.