[Evaluated cases of M1a (non-regional) and recurrent lymph node metastases obtained long-term survival by additional local treatment].

According to the 2014 guidelines for the treatment of Stage IV colorectal cancer, surgical therapy is recommended if R0 resection is possible by resecting both distant metastases and the primary tumor. However, there was no clear evidence regarding the treatment of non-regional lymph node metastases and recurrent lymph node metastases. Thus, we evaluated cases of non-regional lymph node metastases and recurrent lymph node metastases at our hospital from 2005 to the present date. The 5-year overall survival (OS) rate was 50.0%. There was no significant difference in the survival rate between synchronous and metachronous metastases. The survival rate increased significantly in cases that received additional local treatment compared to that in cases that did not receive additional treatment (p=0.013). Multivariate analysis based on the 5-year OS rate of 50.0% revealed a statistically significant difference only in disease free interval (DFI). Although no predictive factor for OS was identified, DFI was considered to be a critical factor. Performing chemotherapy during the perioperative period and determining the appropriate timing of resection based on the response to the chemotherapy and presence/absence of metastases in other organs are expected to increase the survival rate.