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.

Intraductal papillary mucinous tumors of the pancreas: pancreatic resections guided by preoperative morphological assessment and intraoperative frozen section examination.

BACKGROUND: We undertook this study to assess the results of a policy of limited pancreatic resections for intraductal papillary-mucinous tumors (IPMT), guided by a standardized preoperative morphological assessment and the frozen section histologic examination of pancreatic resection margins. METHODS: From 1991 to 1998, there were 41 patients who underwent resection of IPMT in our center after standardized morphological preoperative assessment, including abdominal computed tomography scans, endoscopic retrograde cholangiopancreatography, and endoscopic ultrasonography. All patients but one underwent a partial pancreatic resection. RESULTS: Preoperative assessment had an 89% diagnostic accuracy for IPMT. It detected malignant transformation with a 67% sensitivity and a 95% specificity, but failed to correctly assess ductal extension of the disease in 17 cases (41%). The diagnostic accuracy of frozen section histologic examination of the pancreatic resection margin was 92%. There was no recurrence in case of in situ carcinoma when epithelial lesions were completely resected (8 cases) nor in lower grades of dysplasia (23 cases). Conversely, recurrence was constant in invasive carcinoma (10 cases) regardless of the status of the pancreatic margin. CONCLUSIONS: Frozen section histologic examination of the pancreatic resection margin is useful and reliable to ensure a complete resection of IPMT by a partial resection that prevents recurrence of noninvasive lesions.

In vivo assessment of lipid peroxidation in experimental edematous and necrotizing rat pancreatitis.

Lipid peroxidation, which may be involved in the pathogenesis of acute pancreatitis, is usually assessed in vitro or indirectly using antioxidants or free radical scavengers. We assessed lipid peroxidation in an in vivo model by measuring ethane exhalation in two models of acute pancreatitis. Edematous acute pancreatitis was induced by a supramaximal intraperitoneal injection of cerulein. Necrotizing acute pancreatitis was induced by retrograde infusion of sodium taurocholate into the pancreaticobiliary duct. Rats were placed in closed chambers and ethane exhalation was measured in aliquots. Ethane exhalation was significantly increased (p < 0.002) in cerulein (n = 12)- but not in taurocholate (n = 6)-induced pancreatitis compared to controls (n = 12 and 6, respectively). Our results suggest that free radicals may play a role in the pathogenesis of edematous pancreatitis but do not play an important role in the progression to necrotizing pancreatitis.