PURPOSE: A tumor size of 3cm in diameter has been regarded as the prognostic threshold in the staging of non-small cell lung cancer (NSCLC). The purpose of this study was to assess the accuracy of the T descriptor threshold of 3cm for patients with resected pathological N0 (pN0) NSCLC.
METHODS: From 1994 to 2004, we performed surgical resection in 238 patients with NSCLC, in whom no lymph node metastasis was revealed by pathologic examination. These patients constituted the study population, and their survivals were retrospectively analyzed based on the tumor size of 4 groups (<2.1cm, 2.1-3cm, 3.1–5cm and >5cm). The median follow-up time was 36.6 months (range, 3-162months).
RESULTS: The tumors were classified histologically as 170 adenocarcinomas, 55 squamous cell carcinomas, 6 adenosquamous cell carcinomas, 5 large cell carcinomas, and 3 unclassified carcinomas. Disease-free survivals at 5 years for patients with T1 tumor (n = 118), T2 (n = 91), T3 (n = 18), and T4 (n = 11) were 84.5%, 76.4%, 31.9%, and 54.5%, respectively. When it is distributed according to the tumor size, disease-free survivals at 5 years for patients with <2.1cm tumor (n = 68), 2.1–3cm (n = 61), 3.1–5cm (n = 66), and >5cm (n = 41) were 92.4%, 78.3%, 74.3%, and 51.4%, respectively. Survival rates were similar in 2 groups of 2.1–3cm tumors and 3.1–5cm tumors. When tumor sizes were divided into 3 groups (<2.1cm, 2.1–5cm, and >5cm), disease-free survivals at 5 years for patients were 92.4%, 75.8%, and 51.4%, respectively. There were significant survival differences between 3 groups (p<0.05).
CONCLUSION: These results suggest that the T descriptor threshold of 3cm would not be appropriate for the prediction of survival. The T descriptor should be changed in order to make similar survival groups. We propose a new T criterion that is divided into 3 classifications for tumor size (<2.1cm, 2.1–5cm, and >5cm) in patients without extrapulmonary invasion.
CLINICAL IMPLICATIONS: We propose a new T descriptor that provides us with more accurate prognosis than conventional TNM classification.
DISCLOSURE: Mika Uchiyama, None.