Long-term outcome and prognostic factors for patients with para-aortic lymph node dissection in left-sided colorectal cancer

Background: Para-aortic lymph node (PALN) metastasis of colorectal cancer is rare, and the treatment strategy for PALN metastasis (PALNM) is not established in contrast to liver or lung metastases. We sought to evaluate the survival outcomes and prognostic factors among patients undergoing surgery combined with extended lymphadenectomy for PALNM from left-sided colorectal cancer.

Methods: From 1992 to 2012, 322 patients who underwent PALN dissection (PALND) synchronously with primary resection, among 1819 left-sided colorectal surgical cases, were retrospectively examined. We investigated the overall survival (OS) and prognostic factors for patients with PALNM.

Results: Of the 322 patients, 62 (19.3%) were histologically confirmed to have PALNM. The 5-year OS in patients with and without PALNM was 19.5% and 67.0% (p < 0.001), respectively. Among patients with PALNM, on the multivariable analysis, the positive resection margin (hazard ratio (HR) 3.61; 95% confidence interval (CI) 1.85-7.06), undifferentiated histological type ((por/muc/sig), HR 4.51; 95% CI, 2.22-9.19), ≥ 4 PALNMs (HR 3.34; 95% CI 1.53-7.31), and preoperative CEA ≥ 10 ng/mL (HR 2.1; 95% CI 1.11-4.27) were significant prognostic factors. Among R0 resected cases, the 5-year OS of the 17 cases with ≤ 3 PALNM and well/moderately differentiated adenocarcinoma was 54.2%, which was comparable to that of patients undergoing PALND and diagnosed with stage IIIC (49.6%).

Conclusion: Patients with PALNM of colorectal cancer had a poor prognosis. However, curative resection, ≤ 3 PALNM, and well/moderately differentiated histology type were associated with the long-term survival.