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

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.

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).

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.

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.