Clinical significance of the KRAS G13D mutation in anastomotic recurrence of colorectal cancer

The genetic risk factors for anastomotic recurrence (AR) after curative surgery for colorectal cancer (CRC) are unclear. The present study is a single-center retrospective observational study that aimed to elucidate the association between the KRAS G13D mutation and AR in CRC. The present study included 21 patients with AR and 67 patients with non-anastomotic local recurrence (NALR) following curative surgery for CRC between January 2005 and December 2019. KRAS G13D mutation status was examined by droplet digital polymerase chain reaction. Data of clinicopathological findings and oncological outcomes were analyzed and compared between the AR group and the matched NALR group. The prevalence of the KRAS G13D mutation was significantly higher in the AR group (AR vs. NALR, 33.3 vs. 4.8%; P=0.047). Comparing the KRAS G13D mutation-positive and KRAS G13D mutation-negative patients in the AR group, there was no significant difference in the time from initial surgery to AR or resection rate of AR; however, all patients with KRAS G13D mutation who underwent resection of AR had subsequent recurrence within 2 years after resection, and overall survival was poor (3-year survival rate: Positive vs. negative, 68.6 vs. 90.9%; P=0.02). The prevalence of the KRAS G13D mutation was significantly higher in patients with AR, and KRAS G13D-mutant patients with AR had a poorer prognosis than those that were negative for the KRAS G13D mutation. In conclusion, postoperative surveillance and treatment strategies should be considered with attention to the possibility of AR and subsequent recurrence in KRAS G13D-mutant patients.