Impact of comorbidity and treatment pattern on lung cancer survival

Background Lung cancer incidence rate is increasing and it is the 2nd highest in men and 5th in women. While 5-year cancer relative survival rates of lung cancer has been improved, it is the leading cause of cancer death in Korea. Many publications examined the data from single or limited number of hospitals. Thus, the study focused to evaluate survival difference using bigger data set from National Health Insurance Service(NHIS). Subjects and Methods Data on a total 6,779 lung cancer patients were identified with initial diagnosis for 7 years from 2004 to 2010 after 2 years' wash-out period from 2002 to 2003 using the sample cohort data from National Health Insurance Service(NHIS). Among the 6,779 data, patients with at least one treatment record were selected and death cases within the landmark time 2 months and 6 months were removed respectively. Finally 1,011 and 837 patients were captured as landmark time 2 months and 6 months respectively. Kaplan-Meier method was used for conditional 2-year, 5-year and median survival analysis and Cox proportional hazard's model was used to assess the effect of comorbidity and treatment pattern on overall survival. Results Of these patients, 5-year survival rate was highest in surgery after chemo/radiotherapy group as 13.3% in landmark time 2 months and in surgery group as 13.6% in landmark time 6 months, with a median survival of 12.3 months and 17.0 months respectively. Risk of death was higher in CCI(Charson Comorbidity Index) 4-5 group than 0-3, and in upper 9-10 income distribution than lower 0-2. Patients who received chemotherapy, radiotherapy, non-surgery with chemo/radiotherapy showed higher death risk than those who received surgery only. Mild liver disease and peptic ulcer were most commonly seen comorbidities over all treatment patterns. Myocardial infarction, diabetes with chronic complication, renal disease and congestive heart failure were associated with decreased conditional survival times. Conclusion It is crucial to initiate cancer treatment as soon as possible once lung cancer is diagnosed and intensively manage comorbid diseases together for long-term survival. In addition, various policies and methods for treatment access by lower-income group should be developed.open석