Cancer histology in metastatic lymph node predicts prognosis in patients with node-positive stage IV colorectal cancer.

ABSTRACT

Background: Appropriate prognostic indicators are required for patients with stage IV colorectal cancer (CRC). Lymph node metastasis mainly involves four histological types of CRC. Some metastatic lymph nodes (mLNs) showing cribriform carcinoma are associated with distant metastasis in patients with node-positive CRC and are correlated with recurrence and survival in stage III disease. However, the significance of mLN histology in the prognosis of patients with node-positive stage IV disease remains unclear. Methods: We enrolled 449 consecutive patients with CRC who underwent primary tumor resection with lymph node dissection between January 2011 and November 2018. This study included 88 patients with node-positive stage IV CRC and synchronous or metachronous distant metastases. We retrospectively investigated the association between cancer histology in the mLNs based on our classification and cancer-specific survival (CSS) in patients with node-positive stage IV CRC. Results: Kaplan-Meier analysis showed that CSS was better in patients with CRC and all the mLNs showing tubular-type carcinoma. In contrast, patients with at least some mLNs showing poorly differentiated-type carcinoma had poor prognosis. Multivariate analysis showed that "all mLNs showing tubular-type carcinoma" was an independent good prognostic factor for CSS in patients with node-positive stage IV CRC. In addition, "at least some mLNs showing poorly differentiated-type carcinoma" was an independent poor prognostic factor for CSS in patients with node-positive stage IV disease. Conclusions: The histological type of the mLN may indicate a better or poor prognosis for patients with stage IV CRC.