Long-term outcomes of resection of synchronous paraaortic lymph node metastasis of left-sided colorectal cancer: A multicentre study.

Abstract

The standard treatment strategy for left-sided colorectal cancer with synchronous paraaortic lymph node metastasis (PALNM) remains unclear. Therefore, we aimed to evaluate the long-term outcomes of resection of synchronous PALNM of left-sided colorectal cancer and identify the prognostic factors. In total, 105 patients who underwent resection of synchronous PALNM of left-sided colorectal cancer, with or without other distant metastases, at 36 institutions in Japan between 2011 and 2015 were included in this study. Patients who underwent R0 and R1/2 resections were defined as the R0 and R1/2 groups, respectively. The long-term outcomes of resection of synchronous PALNM and the prognostic factors were investigated. The 5-year overall survival (OS) rate in the entire cohort was 35.5%, and the presence of metastasis other than PALNM was identified as an independent prognostic factor for OS. Of 105 patients, 69 and 36 patients were in the R0 and R1/2 groups, respectively. The 5-year OS rates in the R0 and R1/2 groups were 43.4% and 21.2%, respectively (p = 0.13), and the 5-year relapse-free survival (RFS) rate in the R0 group was 17.3%. In the R0 group, the number of PALNMs ≥3 was identified as an independent prognostic factor for OS, whereas the number of PALNMs ≥3, preoperative carcinoembryonic antigen level ≥10 ng/mL, pathological N stages 1-3, and lack of adjuvant chemotherapy were identified as independent prognostic factors for RFS. R0 resection of synchronous PALNM of left-sided colorectal cancer can confer a survival benefit. However, indications for resection of synchronous PALNM should be carefully considered, particularly in patients with metastasis other than PALNM or those at high risk of R1/2 resection. Among patients who underwent R0 resection, the presence of three or more PALNMs was an independent factor associated with poor outcomes in both OS and RFS.