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

Abstract

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. 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. 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. 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.