Number of examined lymph nodes and nodal status assessment in pancreaticoduodenectomy for pancreatic adenocarcinoma

Background The accuracy of the assessment of the nodal status in resected cephalic pancreatic adenocarcinoma (PA) depends on the number of examined lymph nodes (NELN). This study assesses the impact of the NELN on N staging and survival and propose a minimal number of examined lymph nodes (MNELN) ensuring reliability of the pN status determination. Methods 188 consecutive patients treated by pancreaticoduodenectomy (PD) for PA. Correlations between NELN and survivals of pN0 and pN1 groups and with the rate of pN1 patients were studied. A probability model based on the binomial law was built to estimate the MNELN able to detect pN1 patients with a sensitivity ≥95%. Results Overall and disease free 5-year survivals were 27.2% and 24.6% respectively. 135 patients (71.8%) were staged pN1. The median NELN was 17 (range 0–68). Overall and disease free survivals of pN1 patients were not related to NELN. The influence of NELN on survival in pN0 patients due to stage migration did not reach significance. The probability model showed that a MNELN of 16 nodes was required to detect pN1 patients with a sensitivity of 95%. Conclusion A MNELN of 16 is required to assess pN status and should be considered as a quality criterion in future studies and trials on PD for PA.