Lymphatic invasion is a more significant prognostic factor than visceral pleural invasion in non-small cell lung cancer with tumours of 3 cm or less.

BACKGROUND AND

OBJECTIVE

Visceral pleural invasion is an upstaging factor that increases cancer staging from stage IA to IB for tumours of 3 cm or less. However, lymphatic invasion has not been associated with the tumour-node-metastasis (TNM) staging system. The purpose of this study was to compare visceral pleural invasion and lymphatic invasion as prognostic factors.

METHODS

We retrospectively reviewed 353 consecutive patients who underwent curative resection for stage I non-small cell lung cancer (NSCLC) tumours of 3 cm or less. Patients were divided into three groups and compared. Group A contained no invasions; group B contained visceral pleural invasion only and group C had lymphatic invasion only.

RESULTS

Group A patients had stage IA, but group B patients had stage IB tumours. However, group C patients had stage IA tumours. The 5-year recurrence-free survival for the three groups was 86.2%, 71.5% and 48.0%, respectively. There was a significant difference in survival between groups A and C (P = 0.001).Survival was not different between groups A and B (P = 0.547). In a multivariate analysis conducted to determine risk factors for recurrence, lymphatic invasion was a significant independent risk factor for recurrence (hazard ratio = 2.570, P = 0.006). Pleural invasion was not a significant risk factor for recurrence.

CONCLUSION

Lymphatic invasion is a more significant prognostic factor than visceral pleural invasion in NSCLC of 3 cm or less.