Clinical implications of the margin cytology findings and margin/tumor size ratio in patients who underwent pulmonary excision for peripheral non-small cell lung cancer

A pulmonary wedge resection is useful for the treatment of peripheral non-small cell lung cancer (NSCLC). The margin/tumor size ratio (M/T) is a predictor of positive margin cytology findings in these procedures, although the long-term clinical implications remain unclear. This relationship was investigated in this study. Thirty-seven cases with a high surgical risk without additional pulmonary resection were selected from those accrued in a multicenter prospective study of optimal margin distance for pulmonary excision of peripheral NSCLC and followed for more than 5 years (range 5.3-14 years). Both the M/T and margin cytology findings were indicators of cancer recurrence and survival. All seven cases of surgical margin recurrence had a cytology-positive surgical margin. The 5-year survival rate was 54.2% (n = 24) for M/T < 1 and 84.6% for M/T a parts per thousand yen 1 (n = 13, P = 0.05), while it was 38.5% for positive margin (n = 13) and 79.2% for negative margin (n = 24) cases (P = 0.001). In addition, the margin cytology findings were an independent prognostic factor. A pulmonary wedge resection for peripheral NSCLC should result in a negative malignant margin, which might be obtained from a sufficient tumor margin ratio of M/T a parts per thousand yen 1.