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

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Abstract

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.

Introduction

Nodal involvement impairs survival after pancreatic resection for pancreatic adenocarcinoma (PA).1, 2, 3 The Minimal Number of Examined Lymph Nodes (MNELN) able to insure the accuracy of the nodal status assessment has been established in colorectal4 and gastric cancers5 and integrates clinical practice. As an example, adjuvant treatment after surgical resection of colorectal cancer is usually indicated for pN0 tumours if the MNELN is not reached. On the opposite, for resected PA, consensual indications of adjuvant therapies are presently independent of the nodal status.6 Adjuvant gemcitabine6 or radio-chemotherapy7, 8 are therefore proposed by most centres for N0 and N+ patients which have contributed to the scarcity of available studies on the MNELN in PA.9 Nevertheless, there are strong arguments to define the MNELN in PA. First, it would help to standardize the prognostic implications of nodal involvement in PA and the known influence of the underestimation of nodal involvement on survival curves of N0 and N+ patients by stage migration.4 Second, the refinement of the indications for adjuvant therapy that is likely to occur in the near future, and finally, the need for standardization of both surgical resections and pathological examinations in future trials of therapeutic strategies in PA. This study aims therefore to determine the MNELN ensuring reliable detection of nodal involvement in resected cephalic PA.

Section snippets

Patients

All patients who underwent pancreatoduodenectomy (PD) for cephalic PA in two universitary French centers from 1996 to 2009 were prospectively included in a computerized database and retrospectively analysed. The diagnosis of PA was confirmed by a specialized gastro-intestinal pathologist from each centre.

In both centers, liver and peritoneal metastases contraindicated PD leading to endoscopic palliatives procedures, or surgical biliary and gastric bypasses if discovered at laparotomy. Patients

Results

After application of the exclusion criteria, 188 patients were included in this study, with 122 patients from one centre (HSA) and 66 from the other one (HAP). Median age was 64 years and 117 patients (62%) were men. Eighty percent of patients had jaundice (Total bilirubin > 30 μmol/l) and 15% had a preoperative weight loss > 5%.

In 39 patients (21%), a mesentericoportal venous resection was performed. Postoperative mortality rate at 90 days was 1%. Morbidity rate was 40.2% (76 patients), with

Discussion

The prognostic value of the nodal status13, 14 described by the TNM classification and the Lymph Node Ratio1, 15, 16, 17 in cephalic PA treated by PD is confirmed here by the influence of both pN1 status and the Lymph Node Ratio > 0.2 on overall and disease free survivals. The three methods used to assess the MNELN able to ensure reliable detection of pN1 status were concordant. First, the influence of the NELN on the survival of the pN0 group of patients was almost significant despite its

Conflict of interest statement

Authors don't have any financial or personal relationships with other people or organisations that could inappropriately influence (bias) their work.

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