Diameter of Non-small Cell Lung Cancer Correlates With Long-term Survival : Implications for T Stage

Study objectives: To determine the effect of tumor diameter on the long-term survival of patients with stage I non-small cell lung cancer (NSCLC) within a large multi-institutional database, and to assess the accuracy of the T-descriptor threshold of 3 cm.Design and patients: A total of 9,191 patients ≥ 20 years old with surgically treated stage I NSCLC ≤ 6 cm registered in the Surveillance, Epidemiology, and End Results database from 1992 to 1997 were included. The size of the nodule was grouped into six categories: < 1 cm (n = 191, 2%), 1 to 1.9 cm (n = 2,130, 23%), 2 to 2.9 cm (n = 2,851, 31%), 3 to 3.9 cm (n = 1,984, 22%), 4 to 4.9 cm (n = 1,161, 13%), and 5 to 6 cm (n = 874, 9%). Due to its limited sample size, subcentimeter nodules were not included in the survival analysis. Survival analyses were performed with Kaplan-Meier estimates, log-rank tests, and Cox proportional hazards models.Measurements and results: A total of 4,904 (53%) men and 4,287 women (mean ± SD age, 66.6 ± 9.4 years) with stage I NSCLC were analyzed. The use of lobectomies and pneumonectomies as surgical treatment instead of limited resections increased with the size of the tumor, from 62% in subcentimeter nodules to 96% in 5- to 6-cm tumors (p < 0.0001). Survival decreased with increasing size of the tumor (p < 0.0001). There was a significant survival difference when size groups were compared to tumors 1.0 to 1.9 cm: 2.0 to 2.9 cm (hazard ratio [HR], 1.3; 95% confidence interval [CI], 1.16 to 1.47), 3.0 to 3.9 cm (HR, 1.49; 95% CI, 1.32 to 1.69), 4.0 to 4.9 cm (HR, 1.82; 95% CI, 1.59 to 2.08), and 5.0 to 6.0 cm (HR, 2.04; 95% CI, 1.77 to 2.36). Survival was similar in tumors between 2.0 to 2.9 cm and 3.0 to 3.9 cm, and in tumors between 4.0 to 4.9 cm and 5.0 to 6.0 cm.Conclusions: The T descriptor should be changed so that T1 is reserved for tumors < 2 cm. Further refinement of larger tumors into T2a (2 to 3.9 cm) and T2b (≥ 4 cm) should be considered.