Impact of skip lymph node metastasis on the prognosis of gastric cancer patients who underwent curative gastrectomy

Purpose: Skip metastasis (SK) is an exceptional pattern of lymph node metastasis and the incidence of skip metastasis is not infrequent in gastric cancer (GC). In the present study, we evaluated the clinical significance of skip LN metastasis in GC patients. Methods: According to the anatomical location of positive lymph nodes (LNs), the patients who underwent curative gastrectomy in our institute were classified in three groups: only perigastric involvement (PG group), only extraperigastric involvement (SK group) and both perigastric and extraperigastric involvement (PG+EP group). The clinicopathologic features and prognostic differences between the different groups were compared. Results: The incidence of skip metastasis was 3.9% in all GC patients and the most common location of skip metastasis was No.7 and No.8a node station. The proportion of only one involved station accounted for 83.0% of all cases. In addition, the SK group had fewer numbers of retrieved LNs than the PG and the PG+EP group, especially in the perigastric area. There were significant differences between different groups in the baseline characteristics. After clinicopathologic factors were adjusted and matched, we found that the prognosis of skip metastasis was poorer than that of only perigastric involvement, but was similar to that of both perigastric and extraperigastric involvement. Conclusion: The patients with skip metastasis had a poorer prognosis than those with only perigastric involvement. Anatomical location of metastatic LNs may be not ignored, and adequate lymphadenectomy should be indispensable for node-positive patients.