Characteristics and prognostic factors of node-negative non-small cell lung cancer larger than 5 cm.

OBJECTIVES: In the 7th edition of the tumour, node and metastasis staging system, a primary tumour size larger than 5 cm was shifted to Stage II. Therefore, we aimed to evaluate the characteristics and prognostic factors of node-negative non-small cell lung cancer (NSCLC) larger than 5 cm.

METHODS: We included 109 patients who underwent curative resection and had pathologically confirmed node-negative NSCLC >5 cm (Group 1). We compared the clinicopathological characteristics and prognosis of these patients with 85 patients with node-positive NSCLC >5 cm (Group 2) and 383 patients who had node-positive NSCLC ≤5 cm (Group 3).

RESULTS: Compared with Group 2, old age and absence of lymphovascular invasion was significantly more common in Group 1. Compared with Group 3, frequency of non-adenocarcinoma type and visceral pleural invasion were significantly higher in Group 1; however, the frequency of lymphovascular invasion was higher in Group 3. A Cox proportional hazards model showed that the maximized standardized uptake value and visceral pleural invasion was a statistically worse prognostic factor. Compared with Group 2, Group 1 showed significantly longer overall survival; however, there was no difference in recurrence-free survival. Compared with Group 3, there was no significant difference in recurrence-free survival and overall survival. In Group 1, recurrence in the contralateral lung was the most common recurrence pattern, and there was no metastasis in the mediastinal lymph nodes.

CONCLUSIONS: Patients with node-negative NSCLC >5 cm had a lower incidence of lymphovascular invasion and a more common contralateral recurrence than patients with node-positive NSCLC, and visceral pleural invasion was identified as independent prognostic factors.