Introduction and objectives: To determine the causes of death in patients operated on for stage IB non-small cell lung cancer (NSCLC) and to assess the impact on survival of the number of lymph nodes removed.
Patients and method: We studied 300 patients operated on for stage IB NSCLC. Only palpable or visible lymph nodes were excised. Kaplan-Meier survival estimates were calculated and the survival curves were compared using the log-rank test.
Results: The mean (SD) age of the patients was 62.9 (9.7) years; 280 were men, 20 were women. Pneumonectomy was performed in 84 patients, lobectomy in 186, double lobectomy in 23, and segmentectomy in 7. Squamous cell carcinoma was the most common histologic type. The mean number of lymph nodes excised was 5.05 (5.01). At the time of the study 201 patients (67%) had died, 63.2% from causes related to the NSCLC. Overall 5-year survival for the patient series was 51.9% (median, 5.50 years; 95% confidence interval [CI], 4.14-6.87 years), though the 5-year survival rate was 61.87% after non-NSCLC-related deaths were excluded (median, 11.05 years; 95% CI, 7.63-14.48 years). Tumor size and the number of lymph nodes examined significantly affected survival. In the multivariate analysis, these 2 variables were also significantly correlated with the risk of death from NSCLC (P<.0001), with relative risks of 1.158 (95% CI, 1.081-1.240) and 0.387 (95% CI, 0.254-0.591), respectively.
Conclusion: Besides being affected by stage and tumor size, survival in patients operated on for stage IB NSCLC is significantly influenced by the total number of lymph nodes examined. Therefore, surgical treatment of such patients should include the examination of as many lymph nodes as possible.