The Significance of Skip Lymph Node Metastasis in Colorectal Cancer

The purpose of this study was to elucidate the status and clinical significance of skip lymph node metastasis (LNM) in colorectal cancer.

This is a retrospective cohort study from a high-volume cancer center in Japan. A total of 1,060 patients with primary stage III colorectal cancer (CRC) underwent radical resection were included in the study and divided into skip LNM (LNM) (skip+) and non-skip LNM (skip-) groups. Propensity score matching was used to balance potential confounding factors. The cancer-specific survival (CSS) and relapse-free survival rate (RFS) between the two groups before and after matching were evaluated.

Before matching, patients in the skip+ group had a greater number of LNM (pN2: 48.3% vs. 31.1%; p<0.001), more pathological stage IIIC (43.2% vs. 17.6%; p<0.001), and a higher rate of recurrence (38.1% vs. 25.8%; p=0.0045). Consequently, the CSS (p=0.034) and RFS (p=0.005) were worse compared to the skip- group. However, after matching, there were no significant differences in prognosis for CSS (p=0.529) and RFS (p=0.515). In multivariate analysis, skip+ was not an independent risk factor for prognosis. However, the skip+ LNM group was more likely to have local lymph node recurrence.

Skip+ LNM was more likely to happen in later stage CRCs, leading to significantly poorer survival outcomes. However, when all background factors were matched, the prognosis of the skip+ group was not worse. Surgeons need to be more alert to the possibility of local recurrence in patients with skip LNM.