Venous Resection Research Articles

Outcome of pancreatoduodenectomy with venous resection and reconstruction in locally advanced pancreatic head cancer

Outcome of pancreatoduodenectomy with venous resection and reconstruction in locally advanced pancreatic head cancer

Venous resection in pancreatic cancer surgery: Short and long-term results from a tertiary cancer center

Venous resection in pancreatic cancer surgery: Short and long-term results from a tertiary cancer center

Better Therapy for Pancreatic Cancer through More Radical Surgery?

Despite advances in the treatment of pancreatic cancer, the survival of affected patients remains limited. A more radical surgical therapy could help to improve the prognosis, in particular by reducing the local recurrence rate, which is around 45% in patients with resected pancreatic cancer. In addition, patients with oligometastatic pancreatic cancer could also benefit from a more radical indication for surgery.Based on an analysis of the literature, important principles of pancreatic cancer surgery were examined.Even if even more radical surgical approaches such as an "extended" lymphadenectomy or a standard complete pancreatectomy do not bring any survival advantage, complete resection of the tumour (R0), a thorough locoregional lymphadenectomy and an adequate radical dissection in the area of the peripancreatic vessels including periarterial nerve plexuses should be the standard of pancreatic carcinoma resections. Whenever necessary to achieve an R0 resection, resections of the pancreas have to be extended, as well as additional venous vascular resections and multivisceral resections had to be performed. Simultaneous arterial vascular resections as part of pancreatic resections as well as surgical resections in oligometastatic patients should, however, be reserved for selected patients. These aspects of the surgical technique in pancreatic carcinoma mentioned above must not be neglected from the point of view of an "existing limited prognosis". On the contrary, they form the absolutely necessary basis in order to achieve good survival results in combination with system therapy. However, it may always be necessary to adapt these standards according to the age, comorbidities and wishes of the patient.

Laparoscopic Pancreatoduodenectomy with Resection of the Inferior Vena Cava and Reconstruction with a Peritoneal Patch.

Laparoscopic resection of the inferior vena cava (IVC) during laparoscopic pancreatoduodenectomy (LPD) has never been described. A 32-year-old male with large solid pseudopapillary neoplasm underwent LPD with resection of the IVC and reconstruction by a peritoneal patch (PP). In this indication, the dissection is achieved by resection of the IVC. Kocher maneuver is difficult owing to the caval invasion, and section of the retroportal lamina tissue, before Kocher maneuver, is needed to control the left side of the IVC. Extended lymphadenectomy is not needed because the risk of lymph node invasion is low, and venous resection may be required for severe tumor adhesions without necessary histological invasion, to avoid tumor rupture at high risk of recurrence.1,2 The IVC was clamped by a laparoscopic vascular clamp and reconstructed (5-6 cm) with a PP. The operative duration was 430 min, including IVC clamping for 27 min. The outcome was marked by biliary fistula and 24 days of hospital stay. Histology showed 6 cm tumor without histological invasion of the IVC wall. After 15 months of follow-up, there was no recurrence and no stenosis of the IVC. In our experience, reconstruction of the IVC with a PP is a safe procedure, with no PP-related complications and high patency rate (> 90%).3 CONCLUSION: Laparoscopic resection of the IVC is feasible in highly selected centers. The harvesting of the PP is easier than that of other autologous venous grafts, especially when done by the laparoscopic approach.

An example of “pancreatic Pringle maneuver” during a distal pancreatectomy with venous resection

An example of “pancreatic Pringle maneuver” during a distal pancreatectomy with venous resection

Impact of prior biliary stenting on diagnostic performance of endoscopic ultrasound for mesenteric vascular staging in patients with head of pancreas and periampullary malignancy

ObjectiveThe diagnostic performance of endoscopic ultrasound (EUS) for stratification of head of pancreas and periampullary tumours into resectable, borderline resectable and locally advanced tumours is unclear as is the effect...

Upfront versus resection after neoadjuvant chemotherapy for pancreatic adenocarcinomas with venous contact: comparative analysis of operative and survival outcomes

BackgroundNeoadjuvant treatment before resection for pancreatic adenocarcinoma having contact with the splenomesentericoportal venous axis could improve the results of extended pancreatectomies. We compared the outcomes of upfront (UR) and resection after neoadjuvant chemotherapy (NAC) for pancreatic adenocarcinoma. MethodsWe retrospectively reviewed clinical data of patients who underwent pancreaticoduodenectomy with venous resection for pancreatic adenocarcinoma between January 1, 2006, and December 31, 2020. Operative, pathologic, and survival outcomes were compared between upfront and resection after neoadjuvant chemotherapy. ResultsOf the 169 patients, 55 patients underwent preoperative chemotherapy and 114 underwent upfront. No differences were found in operative time, morbidity, and mortality between the 2 groups. At pathologic examination, patients who underwent resection after neoadjuvant chemotherapy had a significantly smaller tumor size, higher rate of R0 resection, less lymph node involvement, and a lower rate of pathologic venous invasion (P < .05). The median overall survival was 27.96 months, and the overall survival rates at 1, 3, 5, and 10 years were 82%, 39%, 22%, and 11%, respectively. Multivariate Cox analysis found neoadjuvant treatment (hazard ratio: 0.60; 95% confidence interval: 0.38–0.97; P = .03), and intraoperative transfusion (hazard ratio: 2.25; 95% confidence interval: 1.47–3.46; P = .0002) as independent prognostic factors for overall survival. A dose-dependent effect of perioperative transfusion on overall survival was found (no transfusion, = 2 red blood cells, >2 red blood cells; median overall survival 41.1 months vs 27.01 months vs 19.4 months; P = .0003). ConclusionNeoadjuvant chemotherapy improves the pathologic and survival outcomes of pancreaticoduodenectomy with venous resection for pancreatic adenocarcinomas. The dose-dependent effect of perioperative transfusion on overall survival warrants further investigation.

Robotic versus open pancreaticoduodenectomy with vascular resection for pancreatic ductal adenocarcinoma: surgical and oncological outcomes from pilot experience.

Venous resection and reconstruction (VR) is a feasible surgical technique to achieve optimal outcomes in selected patients with pancreatic ductal adenocarcinoma (PDAC) who undergo open pancreaticoduodenectomy (OPD). However, data regarding patient outcomes in patients who undergo VR in robotic-assisted pancreaticoduodenectomy (RPD) are scarce. All patients with a diagnosis of PDAC who underwent upfront open or robotic pancreatoduodenectomy with VR in a high-volume institution for pancreatic surgery between 2011 and 2019 were retrospectively reviewed. Perioperative and long-term outcomes were compared between the RPD and OPD cohorts. A total of 84 patients were included in the final analysis, 14 patients underwent RPD with VR and 70 who had OPD with VR. Reconstructed venous patency, postoperative 30-day morbidity, and 90-day mortality were comparable; however, lymph node resection rates were lower in the RPC cohort (p = 0.029). No difference was identified in 3-year survival rates between the two groups (34.0% versus 25.7% respectively, p = 0.667). RPD with VR is a feasible approach for patients with PDAC and venous invasion. Further studies are needed to assess long-term outcomes compared to the open approach.

Predicting pathologic venous invasion before pancreatectomy with venous resection: When does radiology tell the truth?

BackgroundPatients factors in addition to radiological characteristics could predict the presence of pathologic venous invasion in patients undergoing pancreatectomy with venous resection. MethodsWe tested the predictive value of 6 radiological classification methods for predicting pathologic venous invasion—the Nakao, Ishikawa, MD Anderson, Lu, Raptopoulos, and National Comprehensive Cancer Network methods—on a cohort of 198 pancreatectomies (160 pancreaticoduodenectomies and 38 total pancreatectomies) with venous resection for pancreatic adenocarcinomas. Radiological and clinical factors determining pathologic venous invasion were identified by multivariable logistic analysis. ResultsPathologic venous invasion was detected in 124 patients (63.2%). The multivariable logistic regression analysis identified Lu classification (odds ratio = 1.77, 95% confidence interval =1.34–2.35; P < .0001), elevated serum CA19-9 values (odds ratio = 1.97, 95% confidence interval = 1.00–3.90; P = .04), and preoperative neoadjuvant chemotherapy (odds ratio = 0.38, 95% confidence interval = 0.18–0.79; P = .009) as independent factors associated with pathologic venous invasion. Radiological tumor-vessel contact greater than 50% of the circumference or venous wall deformity was associated with a significantly higher rate of pathological venous invasion (80% vs 52%; P < .0001), deeper (media-intima) venous invasion (47% vs 25%; P < .0001), R1 resection (58% vs 41%; P = .03), higher transfusions (84% vs 66%; P = .005), and arterial resection rates (43% vs 27%; P < .0001). Tumor-vein circumference contact of >50% and/or venous wall deformity was still associated with significantly higher rates of pathologic venous invasion, regardless of whether neoadjuvant chemotherapy was used or not and CA19-9 normalized or not under preoperative treatment. ConclusionPreoperative radiological detection of tumor-vein circumference contact >50% and/or venous wall deformity is associated with up to 80% of cases of pathological venous invasion. The combination of radiologic features with biological (CA19-9) and clinical (presence of preoperative chemotherapy) factors could better refine preoperatively the need for venous resection.

Is Pancreatectomy with Vascular Resection and Reconstruction for Locally Advanced Pancreatic Neuroendocrine Tumors Safe?

Introduction: While pancreatectomy with vascular resection and reconstruction (VR) is commonly performed for locally advanced pancreatic adenocarcinoma, little is known regarding outcomes for pancreatic neuroendocrine tumors (pNETs). Methods: Non-parenchyma-sparing pancreatectomies for pNETs at Mayo Clinic 2000-2020 were retrospectively reviewed. Propensity score matching was performed to adjust for selection bias. Differences between groups were compared with chi-square, Fisher‘s exact, and Mann-Whitney tests and survival assessed using Kaplan-Meier analysis. Results: Of 813 eligible patients, 36 (4.4%) required VR: 22 underwent pancreaticoduodenectomy or total pancreatectomy and 14 distal pancreatectomy. 34 patients had venous resection, one arterial, and one both. Patients requiring VR had larger tumors (median 55 vs. 25 mm, p<0.001), higher grade (84.6% vs. 58.5% grade 2-3, p=0.008), and higher stage (44.4% vs. 19.2% stage 4, p<0.001). After matching, the VR group had longer operative times (median 410 vs. 331 minutes, p<0.001), greater blood loss (47.2% vs. 25.0% >1000 ml, p=0.035), and higher transfusion rates (63.9% vs. 29.2%, p=0.001). Major complications (Clavien-Dindo >/=3) occurred in 41.7% after VR and 25.0% after standard resection (p=0.121). 90-day mortality was 2.8% after VR and 4.2% after standard resection (p>0.999). Over the entire period, overall (p=0.172) and progression-free (p=0.105) survival were not significantly different. On landmark analysis, VR patients had worse overall survival starting at 60 months (p=0.043) and worse progression-free survival starting at 18 months (p=0.044). Conclusion: For patients with locally advanced pNETs, pancreatectomy with VR can be performed in selected patients at high-volume centers with acceptable perioperative morbidity and short- and long-term survival.

Incidence of and Risk Factors for Chyle Leak after Pancreatic Resection: A Nationwide Analysis

Introduction: In 2017 the International Study Group for Pancreatic Surgery (ISGPS) published a consensus definition of chyle leak (CL). Multicenter series assessing the ISGPS-CL definition are lacking and previous studies investigating risk factors for CL used different definitions and showed heterogeneous results. The aim of this study was to assess the clinical impact of the ISGPS-CL definition on incidence, the association with length of stay and mortality, and to assess risk factors of CL. Method: This observational cohort study included patients who underwent pancreatoduodenectomy from the mandatory nationwide Dutch Pancreatic Cancer Audit (2017-2019). Only clinically relevant CL (grade B/C) was included. Prolonged length of stay was defined as more than 14 days. Multivariable logistic regression models were performed. Results: Overall, 2159 patients after pancreatoduodenectomy were included. The rate of CL was 7.0% (n=152), including 6.9% (n=150) grade B and 0.1% (n=2) grade C. After adjustment for confounders, CL was associated with a prolonged hospital stay (OR 2.84, 95% CI 1.85-4.36, p < 0.001). In multivariable analysis, CL was not related to in-hospital mortality. Vascular resection, i.e. arterial and/or venous resections (OR 2.1, 95% CI 1.4-3.2, p < 0.001) and open surgery (OR 3.5, 95% CI 1.7-7.2, p = 0.001) were identified as independent predictors for CL in multivariable analyses, whereas the number of lymph nodes resected and aortocaval lymph node sampling was not. Conclusion: Use of the ISGPS-CL definition is recommended for further studies, to adequately compare results. Risk factors should be taken into account in the postoperative follow-up.

Different Advanced Surgical Approaches for Resection of Tumors Involving the Mesentericoportal Venous System

Introduction: Long term survial in pancreatic cancer depends on radical surgery. Tumor infiltration of the mesentericoportal venous system is not in itself a contraindication for resection provided venous reconstruction is possible. Complication-rates and oncological outcomes after pancreatic surgery with venous resection are in high-volume centers comparable to standard resections. In some cases standard mesentericoportal vein resection is not possible and alternatives have to be considered.

Laparoscopic pancreatectomies for borderline tumors with major venous resections.

Resection of the portal vein or superior mesenteric vein infiltrated by the pancreatic cancer is currently a standard during open pancreatic surgery for cancer. When found intraoperatively it often leads to conversion. Nowadays, research data for laparoscopic pancreatectomies with major venous resections and reconstructions are scarce. To present our own results of laparoscopic total pancreatectomies, pancreaticoduodenectomy and distal pancreatectomies (RAMPS) performed for cancer with major venous resection and reconstructions of the portal system. This is a retrospective study of our own clinical material of consecutive patients treated for adenocarcinoma of pancreas who underwent laparoscopic pancreatectomies with major venous resection and reconstruction in 2020 and 2021. The study included 6 females and 2 males in median age of 68 years (56-77). 6 tumors were located in the pancreatic head, 1 in the pancreatic neck and 1 in the pancreatic body. Surgical procedures included 5 total pancreatectomies, 2 RAMPS and 1 Whipple pancreaticoduodenectomy. There were no conversions. Median time of vascular closure was 55.5 (41-70) min. Median blood loss was 500 (250-900) ml. Median length of hospital stay (LOS) was 18.5 (11-34) days. We observed no complications related directly to vascular resection. Laparoscopic approach for pancreatectomies with portal or superior mesenteric vein resections could be a safe and feasible approach in the hands of an experienced surgeon.

Venous Resection for Locally Advanced Pancreatic Cancer: Time Trend and Outcome Analysis of 80 Consecutive Resections at a High-Volume Center

Introduction: Locally advanced pancreatic cancer (LAPC) is a highly malignant carcinoma with an extremely poor prognosis. Vascular venous invasion is a frequent finding in patients with pancreatic cancer. The aim of this study was to investigate the morbidity, mortality, and survival of patients with advanced pancreatic cancer. Methods: We retrospectively reviewed our experience of 80 consecutive pancreatic surgeries with venous resection for pancreatic cancer in three hospitals: Ramon y Cajal (Madrid, Spain) from 2002 to 2004, Monteprincipe University Hospital (Madrid, Spain) from 2005 to 2006 and Sanchinarro University Hospital (Madrid, Spain) from 2007 to December 2020. Prognostic factors were analyzed by the log-rank test and a multivariate proportional hazard regression analysis. Results: Major venous reconstruction was performed by primary lateral venorrhaphy in 17% of patients, primary end-to-end anastomosis in 70.7% and reconstruction with a Gore-Tex® patch (W.L. Gore & Associates, Inc., Flagstaff, AZ) in 12.3% of patient. In 58% of the patients, the pathological examination showed infiltration of the vascular specimen. About 85% of the procedures performed were R0. The perioperative morbidity rate with Dindo-Clavien classification = III was 21.5%. Tumor size and nodal status were the only prognostic variables, which significantly decreased survival by a multivariate analysis. Conclusions: Major vascular resection to achieve macroscopic tumor clearance can be performed safely with acceptable operative morbidity and mortality. Nevertheless, it is justified only in carefully selected cases.

Changes in Pancreatoduodenectomy over Three Decades to Predict Future Pathological and Operative Complexity

Introduction: Patient selection for pancreatoduodenectomy (PD) is largely based upon local experience and established practice. This study sought to firstly observe changes in complexity and patient cohort over time, then predict characteristics of patients undergoing PD in the future. Method: All PDs at our institution between 1988-2020 were reviewed (n=1,878) to observe changing trends in patient and operative factors. Coefficients from regression models were used to quantify the rate of change over time. The resulting models were then plotted to illustrate the trend across the study period, as well as forecasts for subsequent years. Results: Annual volume (7 to 128) and proportion of pancreatic ductal adenocarcinoma (PDAC) (28 to 53%) increased at a linear rate. The proportion of associated vein resection (3 to 25%) and technical difficulty (type 2-4; 5 to 28%) increased in a nonlinear manner. The average age (48 to 67) increased in a log-linear trend. Length of stay reduced by 9.3%, whilst mortality reduced with an odds ratio of 0.69 per decade. By 2030 average age will increase to 69, PDAC will comprise 62% of pathology, 40% will have associated venous resection and 43% will be graded 2-4 in technical difficulty. Length of stay will reduce to 9.6 days and mortality to 2%. Conclusions: Despite increasing complexity of surgery and patient age, length of stay and mortality after PD are reducing. Understanding changes over time permits an estimation of a future surgical cohort where complexity will increase. It is important that surgeons continue to push boundaries.

P-P49 Predicting Future Pathological and Operative Complexity in Pancreatoduodenectomy: 30 Years of Experience

Abstract Background Patient selection for pancreatoduodenectomy (PD) is largely based upon local experience and established practice. This study sought to observe changes in complexity and patient cohort over time with the aim of predicting future cohort characteristic of patients undergoing PD. Methods All PDs at our institution between 1988 and 2020 were reviewed (n = 1,878) to observe changing trends in patient demographic, pathological diagnosis, operative factors and postoperative outcomes. Coefficients from regression models were reported as gradients per decade, to quantify the rate of change over time. The resulting models were then plotted to illustrate the trend across the study period, as well as forecasts for subsequent years. Results The annual volume (7 to 128) and proportion of pancreatic ductal adenocarcinoma (PDAC) (28 to 53%) increased at a linear rate. The proportion of associated vein resection (3 to 25%) and technical difficulty (type 2-4; 5 to 28%) increased in a nonlinear way, increasing more rapidly in later times. The average age (48 to 67) increased in a log linear trend. Length of stay reduced by 9.3%, whilst mortality reduced with an odds ratio of 0.69, per decade. Furthermore, When performance at our institution was compared to recently established benchmarks, it was shown that our institution regularly performed within these standards with few exceptions. By 2030 our predictions indicate that the average age will increase to 69, PDAC will comprise 62% of pathology, 40% will have an associated venous resection and 43% will be graded 2-4 in technical difficulty. Length of stay will have reduced to 9.6 days and mortality to 2%. Conclusions Despite increasing complexity of surgery and patient age, length of stay and mortality after PD are reducing. Understanding changes over time permits an estimation of a future surgical cohort where complexity will increase. It is important that surgeons continue to push boundaries. Patient selection, based upon prior experience may inhibit progression and development of services.

Falciform ligament tubular graft for mesenteric-portal vein reconstruction during pancreaticoduodenectomy.

Portal vein resection and reconstruction in locally advanced pancreatic cancer represents a potentially curative treatment in selected patients without increasing surgical mortality. However, vascular reconstruction after segmental venous resection is challenging. The parietal peritoneum has emerged as a venous substitute but few reports include its use as a tubular graft. We report a retrospective series of portal vein reconstruction using a falciform ligament tubular graft during pancreaticoduodenectomy. Technical aspects and short-term morbidity and mortality after pancreaticoduodenectomy with falciform ligament tubular graft interposition were analyzed. Among 21 patients who used parietal peritoneum for venous substitution between 2015 and 2019, eight underwent pancreaticoduodenectomy with venous resection and reconstruction using interposition of falciform ligament tubular graft. The mean duration of surgery and clamping time were 350 and 27 min, respectively. No perioperative blood transfusion was required. All the grafts were patent the day after surgery. No complication related to venous obstruction was detected during the hospital stay. Two patients had postoperative pancreatic fistula. No further intervention was needed. The 90-day mortality was null. The use of interposition of falciform ligament tubular graft for portal venous reconstruction during pancreaticoduodenectomy seems to be a reliable, inexpensive, and safe procedure.

Venous wedge and segment resection during pancreatoduodenectomy for pancreatic cancer: impact on short- and long-term outcomes in a nationwide cohort analysis.

Venous resection of the superior mesenteric or portal vein is increasingly performed in pancreatic cancer surgery, whereas results of studies on short- and long-term outcomes are contradictory. The aim of this study was to evaluate the impact of the type of venous resection in pancreatoduodenectomy for pancreatic cancer on postoperative morbidity and overall survival. This nationwide retrospective cohort study included all patients who underwent pancreatoduodenectomy for pancreatic cancer in 18 centres (2013-2017). A total of 1311 patients were included, of whom 17 per cent underwent wedge resection and 10 per cent segmental resection. Patients with segmental resection had higher rates of major morbidity (39 versus 20 versus 23 per cent, respectively; P < 0.001) and portal or superior mesenteric vein thrombosis (18 versus 5 versus 1 per cent, respectively; P < 0.001) and worse overall survival (median 12 versus 16 versus 20 months, respectively; P < 0.001), compared to patients with wedge resection and those without venous resection. Multivariable analysis showed patients with segmental resection, but not those who had wedge resection, had higher rates of major morbidity (odds ratio = 1.93, 95 per cent c.i. 1.20 to 3.11) and worse overall survival (hazard ratio = 1.40, 95 per cent c.i. 1.10 to 1.78), compared to patients without venous resection. Among patients who received neoadjuvant therapy, there was no difference in overall survival among patients with segmental and wedge resection and those without venous resection (median 32 versus 25 versus 33 months, respectively; P = 0.470), although there was a difference in major morbidity rates (52 versus 19 versus 21 per cent, respectively; P = 0.012). In pancreatic surgery, the short- and long-term outcomes are worse in patients with venous segmental resection, compared to patients with wedge resection and those without venous resection.

Categorization of Differing Types of Total Pancreatectomy

Comparability of morbidity and mortality rates after total pancreatectomy (TP) reported by different surgical centers is limited. Procedure-specific differences, such as the extent of resection, including additional vascular or multivisceral resections, are rarely acknowledged when postoperative outcomes are reported. To evaluate postoperative outcomes after TP and categorize different types of TP based on the extent, complexity, and technical aspects of each procedure. This single-center study included a retrospective cohort of 1451 patients who had undergone TP between October 1, 2001, and December 31, 2020. Each patient was assigned to 1 of the following 4 categories that reflect increasing levels of procedure-related difficulty: standard TP (type 1), TP with venous resection (type 2), TP with multivisceral resection (type 3), and TP with arterial resection (type 4). Postoperative outcomes among the groups were compared. Categorization of different types of TP based on the procedure-related difficulty and differing postoperative outcomes. Of the 1451 patients who had undergone TP and were included in the analysis, 840 were men (57.9%); median age was 64.9 (IQR, 56.7-71.7) years. A total of 676 patients (46.6%) were assigned to type 1, 296 patients (20.4%) to type 2, 314 patients (21.6%) to type 3, and 165 patients (11.4%) to type 4 TP. A gradual increase in surgical morbidity was noted by TP type (type 1: 255 [37.7%], type 2: 137 [46.3%], type 3: 178 [56.7%], and type 4: 98 [59.4%]; P < .001), as was noted for median length of hospital stay (type 1: 14 [IQR, 10-19] days, type 2: 16 [IQR, 12-23] days, type 3: 17 [IQR, 13-29] days, and type 4: 18 [IQR, 13-30] days; P < .001), and 90-day mortality (type 1: 23 [3.4%], type 2: 17 [5.7%], type 3: 29 [9.2%], and type 4: 20 [12.1%]; P < .001). In the multivariable analysis, type 3 (TP with multivisceral resection) and type 4 (TP with arterial resection) were independently associated with an increased 90-day mortality rate. The findings of this study suggest there are significant differences in postoperative outcomes when the extent, complexity, and technical aspects of the procedure are considered. Classifying TP into 4 different categories may allow for better postoperative risk stratification as well as more accurate comparisons in future studies.

Clinical Correlates of Portal Venous or Superior Mesenteric Vein Thrombosis Following Neoadjuvant Therapy with Dose Escalated Radiation for Borderline Resectable or Locally Advanced Pancreatic Adenocarcinoma

Neoadjuvant regimens for borderline resectable and locally advanced pancreatic adenocarcinoma (PDAC) are incorporating radiation dose escalation through conventional external beam radiation (EBRT), intraoperative radiation therapy (IORT), and stereotactic body radiation (SBRT). We conducted a retrospective review of patients treated with and without IORT dose escalation to identify risk factors for portal vein and superior mesenteric vein thrombosis (PVT/SMVT).We identified 96 patients with locally advanced or borderline-resectable PDAC treated at our institution with neoadjuvant therapy followed by exploratory laparotomy between 2009 and 2014. Patients considered at risk for close or positive surgical margins based on preoperative imaging were treated with dose escalated RT consisting of EBRT with or without IORT boost to a biological equivalent dose (BED) greater than 100. Prognostic factors for PVT/SMVT were evaluated using the Wilcoxon rank-sum test, Fisher exact test, and Cox proportional hazards model.Median follow-up was 23 months. Fifty-six patients received IORT (58%). Twenty-nine patients (30%) developed PVT/SMVT, fifteen of which (52%) occurred in the setting of local recurrence (LR). Median time to PVT/SMVT was 10 months for patients with and without LR. On multivariate analysis, local recurrence and venous resection and repair with vascular interposition grafts were significantly associated with PVT/SMVT. IORT dose escalation and history of diabetes were not associated with PVT/SMVT. Six patients underwent both IORT and vascular repair, one with vascular interposition graft, of whom 50% developed PVT/SMVT. While the fourteen patients who developed PVT/ SMVT in the absence of LR did not experience a decrease in overall survival, there was significant morbidity associated with PVT/SMVT in this setting, with ten patients developing ascites requiring frequent paracenteses and additional interventions.Approximately 30% of patients who underwent neoadjuvant chemoradiation for PDAC developed PVT/SMVT a median of 10 months following surgery. This was significantly associated with local recurrence and vascular resection with reconstruction with vascular grafts, but not with escalating RT dose. PVT/SMVT in the absence of LR was associated with significant morbidity.