Impact Of Total Retrieved Lymph Nodes On Staging And Survival Of Patients With PT3 Gastric Cancer

Background:The incidence of lymph node metastasis is high in pT3 gastric cancer. However, the impact of total retrieved lymph nodes (tLN) on staging and survival of these patients is not clear, especially on the determination of pT3N0 patients. Also in pT1 and pT2 gastric cancer patients, in whom lymph node metastasis is not so frequent, whether the same problem is exist is unclear, either.Methods:1,895 patients with pT3 gastric cancer who underwent surgery at Yonsei University Medical College from January 1987 to June 2000 were examined in our study. All the patients received radical surgeries. We also evaluated 1,452 pT1 and 885 pT2 patients from the same database.Results: Four hundred sixty patients (24.3%) were diagnosed as pT3N0. Patients with fewer than 31 tLN (25th percentile) had a less advanced N stage than other patients (P<0.001). Lymph node metastasis was positivelyassociated with tLN when a logistic regression was performed (P<0.001; Hazard ratio, 1.014; 95% Cl, 1.006-1.021). With a median 61.1-month follow-up, the overall 10-year survival rate (10-YSR) was 42.8%. pT3N0 patients with fewer than 31 tLN had a 10-YSR of only 55.4%. Although this 10-YSR was not significantly different from NO patients with 31 or more tLN (65.8%; P=0.108), it approached the N1 group (53.3%; P=0.207). When increased this number to 38, this phenomena vanished. pT3N0 patients with fewer than 38 tLN had a 10-YSR of 59.8% (N=233), significantly better than N1 patients (P=0.025).The same phenomena was not seem in pT3N1, pT3N2 or pT1, pT2 patients. In multivariable analyses, tLN emerged as an independent prognostic predictor in pT3N2 and N3 patients but was not one in NO and N1 patients.Conclusions:Increasing number of tLN may improve the accuracy of staging in pT3 patients. Since preoperative nodal staging is difficult, a thorough lymph node dissection is mandatory in all serosa positive patients.