Survival after pathological stage IA nonsmall cell lung cancer: tumor size matters.

BACKGROUND: This study evaluates prognostic factors for survival in completely resected pathological stage IA nonsmall cell lung cancer with special emphasis on tumor size and assesses tumor recurrence rate by actual and actuarial analysis.
METHODS: From January 1989 to December 2001, 130 consecutive resections for pathological stage IA nonsmall cell lung cancer were performed. Pathological tumor size was categorized into 0 to 20 mm and 21 to 30 mm. Each patient was scaled according to the Charlson Comorbidity Index. The Kaplan-Meier method was used for estimation of actuarial recurrence rate and the cumulative incidence method was used to estimate the actual recurrence rate. Risk factors for overall and disease free survival were determined by univariate and multivariate Cox regression analysis.
RESULTS: Overall 5-year survival for patients with tumors 0 to 20 mm and 21 to 30 mm was 69% and 51%, respectively (p = 0.038). Disease-free survival at 5 years was 68% and 48%, respectively (p = 0.015). Only 27 patients had a recurrence and 69 patients died during follow-up. The actual 10-year recurrence rate was lower than the actuarial recurrence rate (23% vs 29%). Larger tumor size (relative risk 1.6; 95% confidence interval 1.0 to 2.7), Charlson Comorbidity Index score greater than or equal to 3 (relative risk 3.7; 95% confidence interval 1.7 to 8.0), and pneumonectomy (relative risk 2.1; 95% confidence interval 1.1 to 4.2) independently predicted adverse outcome.
CONCLUSIONS: Tumor size affects survival in resected stage IA nonsmall cell lung cancer. Current definition of stage IA disease should be substaged into two separate stages. In patients with early-stage lung cancer and relatively good prognosis actual recurrence rate is more realistic than the actuarial recurrence rate.