Effects of the Largest Metastatic Lymph Node Size on the Outcomes of Patients who Underwent Pancreaticoduodenectomy for Pancreatic Ductal Adenocarcinoma

OBJECTIVES: Prognostic importance of metastatic lymph nodes in pancreatic cancer is always garnered attention due to dismal prognosis, with some quantitative factors drawing attention for significantly predicting outcomes. Size is one of the easy approach morphological characteristics of the lymph node, and data for effect of largest metastatic lymph node (LMLN) size on survival outcomes are lacking in pancreatic cancer. We aim to evaluate the effect of LMLN size on the prognosis of patients with pancreatic ductal adenocarcinoma (PDAC). METHODS: This retrospective study evaluates the effect of LMLN size on survival outcomes by grouping the patients who were surgically treated for PDAC, according to their lymph node stage and calculated cutoff value for LMLN size, between February 2015 and May 2020. RESULTS: In the study cohort of 131 patients, the mean age was 63.9±10.8 years and 77 patients were female. Ninety-nine of the patients had pN1, 32 had pN2 stage disease. The optimal cutoff point of LMLN size for predicting the prognosis was calculated as 7.5 mm (sensitivity = 81% and specificity = 81%). 34 (34.3%) of pN1 and 7 (21.9%) of pN2-staged patients had lymph node smaller than 7.5 mm. Three-year survival was significantly longer for patients whose LMLN size was <7.5 mm (56.2–18.2%, p<0.001). Whereas, the patients with LMLN size <7.5 mm had statistically significant longer median survival rate in the subgroup of patients with pN1 lymph node stage, no significant difference in median survival rates was observed between subgroups of pN2 patients (p=0.237). CONCLUSION: The present study demonstrated that the LMLN size was one of the potential predictors of survival in patients with PDAC.