Vein resection without reconstruction (VROR) in pancreatoduodenectomy: expanding the surgical spectrum for locally advanced pancreatic tumours

Pancreatoduodenectomy with superior mesenteric vein resection and non-reconstruction for pancreatic head cancer paying particular attention to hemodynamics

PURPOSE

Locally advanced pancreatic ductal adenocarcinoma (PDAC) with an unreconstructible superior mesenteric vein (SMV) invasion is one of the criteria of unresectability in the National Comprehensive Cancer Network guidelines. Advances in chemotherapy have improved downstaging and conversion surgery outcomes, thereby broadening surgical options for locally advanced PDAC. However, operations for PDAC with an unreconstructible SMV is less well-documented. If the collateral route is well-developed and can be preserved or reconstructed, SMV resection can be performed without reconstruction. In this paper, we detail our surgical technique and the outcomes for patients undergoing pancreatoduodenectomy with SMV resection and non-reconstruction (PD-SMVR-NR).

METHODS

All consecutive patients with pancreatic head cancer who underwent PD at Juntendo University Hospital, Japan, between January 2019 and December 2022 were evaluated from a prospectively maintained preoperative database. Demographic data, clinical history, operative record, morbidity, mortality, and pathologic data were reviewed.

RESULTS

Over four years at our Institute, 161 patients with pancreatic head cancer underwent PD, and 86 of these patients underwent PD with portal vein (PV) or SMV resection. There were three patients who underwent PD-SMVR-NR. Each patient had well-developed collateral vessels bypassing the obstructed segment of the SMV. All three patients had no hospital mortality with acceptable complications (Clavien-Dindo grade 2). Two patients achieved R0 resection.

CONCLUSION

By understanding the hemodynamics of venous flow and preserving collateral vessels, especially the superior right colic vein arcade and porto-mesenterico-splenic confluence, pancreatoduodenectomy with superior mesenteric vein resection and non-reconstruction can be performed safely.

Pancreatectomy with En Bloc Superior Mesenteric Vein and All Its Tributaries Resection without PV/SMV Reconstruction for "Low" Locally Advanced Pancreatic Head Cancer

The "vein definition" for locally advanced pancreatic ductal adenocarcinoma (LA PDAC) assumes portal-to-superior mesenteric vein (PV/SMV) unreconstructability due to tumor involvement or occlusion. Radical pancreatectomies with SMV resection without PV/SMV reconstruction are scarcely discussed in the literature. Retrospective analysis of 19 radical pancreatectomies for "low" LA PDAC with SMV and all its tributaries resection without PV/SMV reconstruction has shown zero mortality; overall morbidity-56%; Dindo-Clavien-3-10.5%; R0-rate-82%; mean operative procedure time-355 ± 154 min; mean blood loss-330 ± 170 mL; delayed gastric emptying-25%; and clinically relevant postoperative pancreatic fistula-8%. In three cases, surgery was associated with superior mesenteric (n2) and common hepatic artery (n1) resection. Surgery was completed without vein reconstruction (n13) and with inferior mesenteric-to-splenic anastomosis (n6). There were no cases of liver, gastric, or intestinal ischemia. A specific complication of the SMV resection without reconstruction was 2-3 days-long intestinal edema (48%). Median overall survival was 25 months, and median progression-free survival was 18 months. All the relapses, except two, were distant. The possibility of successful SMV resection without PV/SMV reconstruction can be predicted before surgery by CT-based reconstructions. The mandatory anatomical conditions for the procedure were as follows: (1) preserved SMV-SV confluence; (2) occluded SMV for any reason (tumor or thrombus); (3) well-developed inferior mesenteric vein collaterals with dilated intestinal veins; (4) no right-sided vein collaterals; and (5) no varices in the upper abdomen. Conclusion: "Low" LA PDACs involving SMV with all its tributaries can be radically and safely resected in highly and specifically selected cases without PV/SMV reconstruction with an acceptable survival rate.

Extent of venous resection during pancreatectomy-finding the balance of technical possibility and feasibility

The improvement of effective multidrug agents has allowed more patients to undergo resection for pancreatic cancer (PC). In the conversion cases of initially unresectable PC after induction chemotherapy, pancreatic surgeons often encounter challenging vein resections cases such as those of long-segment portal vein (PV)/superior mesenteric vein (SMV) encasement or occlusion of the distal (caudal) SMV. Given the lack of consensus for the optimal approach for major vein resections and reconstructions in these situations, this review summarizes the literature on this topic and provides the best currently available approaches for challenging vein reconstruction cases. For long-segment PV/SMV encasement, tips for direct end-to-end anastomosis without grafts and the splenic vein (SpV) reconstruction to prevent left-side portal hypertension will be introduced. For distal SMV encasement, several bypass techniques to deal with collateralizations will be introduced. Even though some high-volume PC centers are obtaining favorable outcomes for challenging vein resection cases, existing evidence on this topic is limited. It is essential to organize the well-designed international multicenter studies for the small population of challenging vein resection cases. With the emergence of effective chemotherapies, the number of PC patients who can undergo curative resection is increasing. Achieving more successful vessel resection and reconstruction in the treatment of PC is a common goal that pancreatic surgeons should focus on together.

Surgery for pancreatic cancer: current controversies and challenges

Two areas that remain the focus of improvement in pancreatic cancer include high post-operative morbidity and inability to uniformly translate surgical success into long-term survival. This narrative review addresses specific aspects of pancreatic cancer surgery, including neoadjuvant therapy, vascular resections, extended pancreatectomy, extent of lymphadenectomy and current status of minimally invasive surgery. R0 resection confers longer disease-free survival and overall survival. Vascular and adjacent organ resections should be undertaken after neoadjuvant therapy, only if R0 resection can be ensured based on high-quality preoperative imaging, and that too, with acceptable post-operative morbidity. Extended lymphadenectomy does not offer any advantage over standard lymphadenectomy. Although minimally invasive distal pancreatectomies offers some short-term benefits over open distal pancreatectomy, safety remains a concern with minimally invasive pancreatoduodenectomy. Strict adherence to principles and judicious utilization of surgery within a multimodality framework is the way forward.

Systematic review of the incidence and risk factors for chyle leak after pancreatic surgery

BACKGROUND

The incidence of and risk factors for chyle leak, as defined by the 2017 International Study Group on Pancreatic Surgery, remain unknown.

METHODS

MEDLINE, EMBASE, and Scopus were systematically searched for studies of patients undergoing pancreatectomy that reported chyle leak according to the 2017 International Study Group on Pancreatic Surgery definition. The primary outcomes were the incidence of overall and clinically relevant chyle leak. A random-effects pairwise meta-analysis was used to calculate the incidence of chyle leak.

RESULTS

Thirty-five studies including 7,083 patients were included in the meta-analysis. The weighted incidence of overall chyle leak was 6.8% (95% confidence interval 5.6-8.2), and clinically relevant chyle leak was 5.5% (95% confidence interval 3.8-7.7). Pancreaticoduodenectomy, total pancreatectomy, and distal pancreatectomy were associated with a CL incidence of 7.3%, 4.3%, and 5.8%, respectively. Fourteen individual risk factors for chyle leak were identified from included studies. Younger age, low prognostic nutritional index, para-aortic node manipulation, lymphatic involvement, and post-pancreatectomy pancreatitis were significantly associated with chyle leak, all from individual studies.

CONCLUSION

The incidence of overall chyle leak and clinically relevant chyle leak after pancreatic surgery, as defined by the 2017 International Study Group on Pancreatic Surgery, is 6.8% and 5.5%, respectively. Several risk factors for chyle leak were identified in the present review; however, larger high-quality studies are needed to more accurately define these risks.