Resection of the Portal-Superior Mesenteric Vein in Pancreatic Cancer: Pathological Assessment and Recurrence Patterns.

OBJECTIVES: The portal vein (PV)-superior mesenteric vein (SMV) margin is the most affected margin in pancreatic cancer. This study investigates the association between venous resection, tumor invasion in the resected PV-SMV, recurrence patterns, and overall survival (OS). METHODS: This multicenter cohort study included patients who underwent pancreatoduodenectomy for pancreatic cancer (2010-2017). In addition, a systematic literature search was performed. RESULTS: In total, 531 patients were included, of which 149 (28%) underwent venous resection of whom 53% had tumor invasion in the resected PV-SMV. Patients with venous resection had a significant higher rate of R1 margins (69% vs 37%) and had more often multiple R1 margins (43% vs 16%). Patient with venous resection had a significant shorter time to locoregional recurrence and a shorter OS (15 vs 19 months). At multivariable analyses, venous resection and tumor invasion in the resected PV-SMV were not predictive for time to recurrence and OS. The literature overview showed that pathological assessment of the resected PV-SMV is not adequately standardized. CONCLUSIONS: Only half of patients with venous resection had pathology confirmed tumor invasion in the resected PV-SMV, and both are not independently associated with time to recurrence and OS. The pathological assessment of the resected PV-SMV needs to be standardized.

Does mesenteric venous imaging assessment accurately predict pathologic invasion in localized pancreatic ductal adenocarcinoma?

BACKGROUND: Accurate prediction of mesenteric venous involvement in pancreatic ductal adenocarcinoma (PDAC) is necessary for adequate staging and treatment. METHODS: A retrospective cohort study was conducted in PDAC patients at a single institution. All patients with resected PDAC and staging CT and EUS between 2003 and 2014 were included and sub-divided into "upfront resected" and "neoadjuvant chemotherapy (NAC)" groups. Independent imaging re-review was correlated to venous resection and venous invasion. Sensitivity, specificity, positive and negative predictive values were then calculated. RESULTS: A total of 109 patients underwent analysis, 60 received upfront resection, and 49 NAC. Venous resection (30%) and vein invasion (13%) was less common in patients resected upfront than those who received NAC (53% and 16%, respectively). Both CT and EUS had poor sensitivity (14-44%) but high specificity (75-95%) for detecting venous resection and vein invasion in patients resected upfront, whereas sensitivity was high (84-100%) and specificity was low (27-44%) after NAC. CONCLUSIONS: Preoperative CT and EUS in PDAC have similar efficacy but different predictive capacity in assessing mesenteric venous involvement depending on whether patients are resected upfront or received NAC. Both modalities appear to significantly overestimate true vascular involvement and should be interpreted in the appropriate clinical context.

Meta-analysis and cost effective analysis of portal-superior mesenteric vein resection during pancreatoduodenectomy: Impact on margin status and survival.

INTRODUCTION: The benefit of portal-superior mesenteric vein resection (PSMVR) with pancreatoduodenectomy (PD) remains controversial. This study assesses the impact of PSMVR on resection margin status and survival. METHOD: An electronic search was performed to identify relevant articles. Pooled odds ratios were calculated for outcomes using the fixed or random-effects models for meta-analysis. A decision analytical model was developed for estimating cost effectiveness. RESULTS: Sixteen studies with 4145 patients who underwent pancreatoduodenectomy were included: 1207 patients had PSMVR and 2938 patients had no PSMVR. The R1 resection rate and post-operative mortality was significantly higher in PSMVR group (OR1.59[1.35, 1.86] p=<0.0001, and OR1.72 [1.02,2.92] p = 0.04 respectively). The overall survival at 5-years was worse in the PSMVR group (HR0.20 [0.07,0.55] P = 0.020). Tumour size (p = 0.030) and perineural invasion (P = 0.009) were higher in the PSMVR group. Not performing PSMVR yielded cost savings of $1617 per additional month alive without reduction in overall outcome. CONCLUSION: On the basis of retrospective data this study shows that PD with PSMVR is associated with a higher R1 rate, lower 5-year survival and is not cost-effective. It appears that PD with PSMVR can only be justified if R0 resection can be achieved. The continuing challenge is accurate selection of these patients.

Assessment of surgical resectability of pancreatic adenocarcinomas with multidetector computed tomography: what are the possibilities and problems?

BACKGROUND/AIMS: To investigate the accuracy of multidetector computed tomography (MDCT) in preoperatively determining the surgical resectability of pancreatic adenocarcinomas. MATERIALS AND METHODS: Multidetector computed tomography, surgery, and pathological results of 274 patients with pancreatic adenocarcinoma were evaluated retrospectively. MDCT findings were compared with surgical and pathological findings to determine the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MDCT in determining surgical resectability. RESULTS: A total of 124 of 274 (56%) patients (83 males, mean age: 60 years) underwent laparoscopy and/or laparotomy. The sensitivity, specificity, PPV, NPV, and accuracy of MDCT in determining the surgical resectability of pancreatic adenocarcinomas were 100%, 72%, 78%, 100%, and 86%, respectively. Liver metastases in 9 cases, peritoneal metastases in 3 cases, and vascular invasion in 5 cases, which were determined during surgery, were not reported by MDCT. On re-review of the MDCT images of these 17 patients, no metastatic lesions could be seen in 9 patients with liver metastases and in 2 of 3 patients with peritoneal metastases. In 1 patient, a peritoneal implant of a diameter of 8 mm was missed on MDCT. There was no vascular invasion according to Lu criteria on the MDCT images in the 5 cases that had vascular invasion in the surgical exploration. CONCLUSION: The accuracy of MDCT is high in the preoperative determination of surgical resectability of pancreatic adenocarcinomas, but the detection of small liver and peritoneal metastases and accurate determination of vascular invasion are still major problems. Surgeons should be aware of the limitations of preoperative MDCT.

Assessment of vascular invasion in pancreatic head cancer with multislice spiral CT: value of multiplanar reconstructions.

The use of multiplanar reconstructions (MPRs) generated from multislice spiral CT (MSCT) data sets in the preoperative assessment of vascular invasion in pancreatic cancer was evaluated. Forty patients underwent biphasic high-resolution MSCT prior to surgery for pancreatic head cancer. Image reconstruction included thin-slice axial, sagittal and coronal MPRs as well as an MPR perpendicular to the course of a major peripancreatic vessel in proximity to the tumor. CT criteria for vascular invasion were: (1) circumferential involvement >180 degrees and (2) vessel narrowing. Imaging findings of 52 vessels were correlated with surgical and histopathological reports. Regarding the CT criterion circumferential involvement, vascular invasion was demonstrated on axial MPRs with a sensitivity and specificity of 58 and 97%. For the assessment with coronal and sagittal MPRs sensitivity was only 47%. Vascular invasion was recognized best on perpendicular MPRs with a sensitivity, specificity and accuracy of 74, 97 and 88%, respectively. Vessel narrowing was a less reliable CT criterion for vascular invasion, mainly due to the lower specificity of 91% obtained with each available MPR. Thin-slice MPRs oriented perpendicularly to a possibly invaded vessel exactly depict the grade of circumferential involvement and thus have the capability to improve the assessment of vascular invasion in pancreatic cancer.

Noninvasive assessment of portomesenteric venous thrombosis: current concepts and imaging strategies.

Rapid, noninvasive imaging strategies, especially multidetector spiral CT and CT angiography (CTA) as well as gadolinium-enhanced MR angiography (MRA), have facilitated early diagnosis of splanchnic venous thrombosis, a potentially lethal cause of intestinal ischemia. Single breath-hold volumetric acquisitions permit superior temporal and contrast resolution while eliminating motion artifact and suppressing respiratory misregistration. Increased spatial resolution is aided by thinner slice collimation. These cross-sectional imaging techniques are becoming a preferred noninvasive alternative to conventional selective mesenteric angiography with delayed imaging for venous evaluation and should be considered the primary diagnostic modalities for evaluating patients with high clinical suspicion of nonsurgical mesenteric ischemia.

Dual-phase helical CT of pancreatic adenocarcinoma: assessment of resectability before surgery.

OBJECTIVE: The aim of our study was to prospectively evaluate the accuracy of dual-phase helical CT in the preoperative assessment of resectability in patients with suspected pancreatic cancer using surgical and histopathologic correlation. SUBJECTS AND METHODS: Between January 1999 and December 2000, 76 patients with suspected pancreatic cancer underwent preoperative evaluation and staging with dual-phase helical CT (3-mm collimation for pancreatic phase, 5-mm collimation for portal phase). Iodinated contrast material was injected IV (170 mL at a rate of 4 mL/sec); acquisition began at 40 sec during the pancreatic phase and at 70 sec during the portal phase. Three radiologists prospectively evaluated the imaging findings to determine the presence of pancreatic tumor and signs of unresectability (liver metastasis, vascular encasement, or regional lymph nodes metastasis). The degree of tumor-vessel contiguity was recorded for each patient (no contiguity with tumor, contiguity of < 50%, or contiguity of > or =50%). RESULTS: Thirty-nine patients with pancreatic adenocarcinoma were surgically explored. Curative resections were attempted in 34 patients and were successful in 25. The positive predictive value for resectability was 73.5%. Nine patients considered resectable on the basis of CT findings were found to be unresectable at surgery because of liver metastasis (n = 5), vascular encasement (n = 2), or lymph node metastasis (n = 2). We found that the overall accuracy of helical CT as a tool for determining whether a pancreatic adenocarcinoma was resectable was 77% (30/39 patients). CONCLUSION: Dual-phase helical CT is a useful technique for preoperative staging of pancreatic cancer. The main limitation of CT is that it may not reveal small hepatic metastases.

Pancreatic carcinoma: MR assessment of tumor invasion of the peripancreatic vessels.

OBJECTIVE: Our goal was to determine the value of MRI in the assessment of vascular invasion in the preoperative staging of pancreatic carcinoma. MATERIALS AND METHODS: In 53 consecutive patients with an established diagnosis of pancreatic ductal adenocarcinoma, SE T1-weighted and breath-hold gradient echo images at 0.5 T were obtained before and after bolus injection of Gd-DTPA. Major peripancreatic vessels were evaluated for the presence of (a) no tumor invasion, (b) contiguity with tumor, and (c) tumor encasement. All patients subsequently underwent surgery. Results of unenhanced and contrast-enhanced MRI studies were compared with the histologic findings in the resected specimens in 34 cases and with the surgical findings in 19 nonresected cases. RESULTS: In six patients, pathologic examination showed the presence of tumor confined to the pancreas with no vascular invasion. With MRI, five of these cases were correctly evaluated; in the remaining case, tumor-vessel contiguity was erroneously diagnosed. In 21 patients, tumor contiguity with adjacent vessels was found at pathologic examination. At MRI, 16 of these cases were correctly assessed, and 5 were understaged as tumors confined to the pancreas. Of the remaining 26 patients, 7 had vascular encasement by tumor at pathologic examination of the resected specimen; the other 19 patients had unresectable tumors encasing the adjacent vessels at surgical evaluation. MRI detected vascular encasement in 21 of these 26 cases; in the other 5, tumor contiguity was incorrectly diagnosed. The overall accuracy of MRI for determining vascular invasion was 79%. CONCLUSION: MRI is a helpful method for preoperative assessment of vascular involvement due to pancreatic carcinoma.

Assessment of portal hypertension by endoscopic ultrasonography.

Endoscopic ultrasonography (EUS) was performed in 40 patients with portal hypertension (PH) and in 48 control subjects. The azygous, splenic, mesenteric, and portal veins were displayed in both groups. However, esophageal and gastric varices, periesophageal and perigastric collateral veins, and submucosal gastric venules were displayed only in patients with portal hypertension. EUS was inferior to endoscopy in detecting and grading esophageal varices (p less than 0.0005), but EUS was superior in the detection of varices in the fundus of the stomach (p less than 0.0005). Detection of periesophageal veins by EUS increased with increasing diameter of esophageal varices at endoscopy (57% in grade 1, 89% in grade 2, and 100% in grade 3), and there was a direct correlation between endoscopic grade and the diameter of the periesophageal collateral veins at EUS. The diameter of the azygous vein by EUS at its distal and proximal margins was significantly greater in patients with PH (p less than 0.001); the EUS diameter of the azygous vein was significantly larger with variceal grade 2 compared with grade 1 (p less than 0.02 and p less than 0.01, respectively). In portal hypertensive gastropathy, endoscopic and EUS detection were coincident. No correlation was found between the presence of portal hypertensive gastropathy, endoscopic grade of esophageal varices, and detection of gastric varices at EUS.