Study objective: Despite renewed interest in early detection of lung cancer, the relationship between tumor size and survival remains controversial. The objective of this study was to evaluate the relationship between size and stage in patients with T1 (≤ 3.0 cm) non-small cell lung cancer (NSCLC).
Patients and methods: A retrospective review of a lung cancer database from 1995 to 2003 identified 503 patients with completely resected invasive NSCLC with tumors ≤ 3 cm. All clinical and pathologic characteristics were recorded. Univariate associations between nodal status and other prognostic factors were explored by χ2 and t tests. The independent effect of tumor size > 2 cm vs ≤ 2 cm on the risk of nodal disease was analyzed using a logistic regression model.
Results: Of the 503 patients, 324 patients (64.4%) had stage IA disease, 52 patients (10.3%) had stage IB disease, 37 patients (7.4%) had stage IIA disease, 15 patients (3%) had stage IIB disease, 43 patients (8.6%) had stage IIIA disease, 24 patients (4.8%) had stage IIIB disease, and 8 patients (1.6%) had stage IV disease. One hundred patients (19.9%) had nodal metastases. The mean (± SD) tumor size of cases without nodal disease was 1.90 ± 0.67 cm, compared to 2.18 ± 0.69 cm for node-positive tumors (p = 0.0003; 95% confidence interval [CI] for mean difference, 0.13 to 0.43). Forty-eight of 308 patients (15.6%) with smaller carcinomas (≤ 2.0 cm) compared to 52 of 195 patients (26.7%) with carcinomas > 2.0 cm had nodal metastases (p = 0.002). Exploratory multivariate analysis revealed that only tumor size (≤ 2.0 cm [referent] vs > 2.0 cm) affected nodal status and thus stage (adjusted odds ratio, 2.0; 95% CI, 1.3 to 3.1; p = 0.002).
Conclusions: Primary invasive NSCLC > 2.0 cm was twice as likely to have nodal metastases than carcinomas ≤ 2.0 cm. Our results suggest that in lung cancer smaller lesions may represent earlier stage disease. These results also suggest the need for further subclassification by tumor size within the current International Union Against Cancer/American Joint Committee on Cancer stage I, with tumors < 2 cm in size contained in a separate substage. This refinement may help to better clarify which patients might benefit from novel adjuvant or neoadjuvant therapeutic interventions.