Risk Factors for Recurrence After Lung Cancer Resection as Estimated Using the Survival Tree Method

Background Patients with lung cancer often present with recurrence, even after resection. The identification of risk factors for recurrence after resection is useful. Methods Among 1,338 patients with lung cancer who underwent a complete resection, 277 developed recurrences post surgery. Data regarding the TNM factors, histologic subtype, and presence/absence of vessel invasion were analyzed retrospectively using the survival tree method to identify groups with a high risk of recurrence after resection. Results The results revealed that the T factor, the N factor, and lymphatic (ly) and blood (v) vessel invasion were related to the risk of recurrence, and six combinations of these factors were identified using the survival tree method: group A: v = 0, T ≤ 1b, ly = 0; group B: v = 0, T ≤ 1b, ly ≥ 1; group C: v = 0, T ≥ 2a; group D: v ≥ 1, N ≤ 1, T ≤ 2b; group E: v ≥ 1, N ≤ 1, T ≥ 3; and group F: v ≥ 1, N ≥ 2. The six groups were then further classified into three groups: a low-risk group (group A), a moderate-risk group (groups B, C, and D), and a high-risk group (groups E and F). The 5-year recurrence-free survival rate was approximately 98% for the low-risk group, 75% for the moderate-risk group, and 30% for the high-risk group. Conclusions Combining the T, N, v, and ly factors allowed the precise identification of a group with a high risk of recurrence after resection.