Clinicopathological study of p-T1aN0M0 non-small-cell lung cancer, as defined in the seventh edition of the TNM classification of malignant tumors

Abstract

Objective: The seventh edition of the TNM Classification of Malignant Tumours was published in 2009. The present study was conducted to investigate the clinicopathological features of p-T1aN0M0 non-small-cell lung cancer, which is the earliest stage defined in the new tumor, node, metastasis (TNM) classification, in relation to patient prognosis.

Methods: We retrospectively studied 162 patients, who underwent surgical resection at our institution for p-T1aN0M0 non-small-cell lung cancer, as re-categorized in the seventh TNM classification. Univariate and multivariate analyses of disease-free survival were performed.

Results: The mean tumor size was 13.2 ± 4.7 mm. The maximum tumor diameter was >10 mm in 104 cases (64.6%), and ≤ 10 mm in 58 (35.4%). The median follow-up period was 44.5 months. Univariate analysis showed that the 5-year disease-free survival rate of patients with and without preoperative serum carcinoembryonic antigen elevation was 50.8% and 95.1% (P<0.0001), respectively, that of patients with and without blood vessel or lymphatic invasion was 40.0% and 95.8% (positive vs negative, P<0.0001), respectively, and that of patients aged ≥ 70 years and <70 years was 86.8% and 96.1% (P=0.014), respectively. Multivariate analysis including these three clinicopathologic factors demonstrated that preoperative elevation of the carcinoembryonic antigen level and blood vessel or lymphatic invasion were independent prognostic factors.

Conclusion: In patients with p-T1aN0M0 non-small-cell lung cancer, an elevated preoperative carcinoembryonic antigen level and blood vessel or lymphatic invasion tend to affect prognosis to a greater degree than tumor size. Therefore, the efficacy of adjuvant chemotherapy for these patients should be evaluated in clinical trials.