Positive Lymph Node Ratio as an Indicator of Prognosis and Local Tumor Clearance in N3 Gastric Cancer

Nodal metastasis is an important clinical issue in gastric cancer patients. This study was designed to investigate the clinical usefulness of the positive lymph node ratio (PLNR), which reflects both metastatic and retrieved lymph node numbers, in patients with pN3 gastric cancer. We retrospectively analyzed the records of 138 consecutive pN3 patients who underwent curative gastrectomy with lymphadenectomy from 2000 to 2012. A PLNR of 0.4 was proved to be the best cutoff value to stratify the prognosis of patients with pN3 gastric cancer (P < 0.001). Univariate and multivariate analyses revealed that older age, larger tumor size (aeyen10 cm), and PLNR aeyenaEuroe0.4 [P < 0.001, HR 3.1 (95 % CI 1.7-5.4)] were independent prognostic factors in pN3 gastric cancer. Regarding the recurrence, patients with PLNR < 0.4 had a significantly lower rate of lymph node recurrence than those with PLNR aeyen0.4 (P = 0.020). There was no significant difference in the lymph node recurrence rate between N3a and N3b patients in the PLNR < 0.4 group [P = 0.546, 11.6 % (7/60) vs. 12.5 (1/8)], indicating a better local control regardless of pN3 subgroups. PLNR is useful to stratify the prognosis and evaluate the extent of local tumor clearance in pN3 gastric cancer.