Tips and tricks of the surgical technique for borderline resectable pancreatic cancer: mesenteric approach and modified distal pancreatectomy with en-bloc celiac axis resection

Complete circumferential lymphadenectomy around the superior mesenteric artery with preservation of nerve plexus reduces locoregional recurrence after pancreatoduodenectomy for resectable pancreatic ductal adenocarcinoma

BACKGROUND

Evaluation of recurrence pattern and risk factors for recurrence are essential for good rates of survival after upfront pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC).

METHODS

This retrospective study included 167 consecutive patients who underwent upfront PD for resectable PDAC between 2000 and 2018. Postoperative recurrences were classified into three patterns according to initial recurrence site: isolated locoregional, isolated distant, and simultaneous locoregional and distant recurrences.

RESULTS

This study found 114 patients who developed postoperative recurrence (68.3%), including 37 patients with isolated locoregional recurrence (32.5%), 67 patients with isolated distant recurrence (58.8%), and 10 patients with simultaneous locoregional and distant recurrences (6.0%). When locoregional recurrence was classified based on the location of recurrent lesions, locoregional recurrence most commonly occurred around the superior mesenteric artery (SMA) (70.2%), followed by around the hepatic artery (25.5%) and in the paraaortic region (14.9%). Multivariate analyses showed that complete circumferential lymphadenectomy around the SMA, including not only the right side, but also the left side, was an independent factor for reduction of locoregional recurrence (P = 0.019, odds ratio [OR]: 2.217). Lymph node metastasis was an independent risk factor for both locoregional (P < 0.001, OR: 3.686) and distant recurrences (P < 0.001, OR: 4.315). Non-completion of postoperative adjuvant therapy was a risk factor for distant recurrence (P < 0.001, OR: 3.748).

CONCLUSION

Based on our data, complete circumferential lymphadenectomy around the SMA might contribute to local control, and multidisciplinary treatment including neoadjuvant therapy might be needed for resectable PDAC with high risk for recurrence.

Preoperative assessment of the resectability of pancreatic ductal adenocarcinoma on CT according to the NCCN Guidelines focusing on SMA/SMV branch invasion

OBJECTIVES

For patients with pancreatic adenocarcinoma (PAC), adequate determination of disease extent is critical for optimal management. We aimed to evaluate diagnostic accuracy of CT in determining the resectability of PAC based on 2020 NCCN Guidelines.

METHODS

We retrospectively enrolled 368 consecutive patients who underwent upfront surgery for PAC and preoperative pancreas protocol CT from January 2012 to December 2017. The resectability of PAC was assessed based on 2020 NCCN Guidelines and compared to 2017 NCCN Guidelines using chi-square tests. Overall survival (OS) was estimated using the Kaplan-Meier method and compared using log-rank test. R0 resection-associated factors were identified using logistic regression analysis.

RESULTS

R0 rates were 80.8% (189/234), 67% (71/106), and 10.7% (3/28) for resectable, borderline resectable, and unresectable PAC according to 2020 NCCN Guidelines, respectively (p < 0.001). The estimated 3-year OS was 28.9% for borderline resectable PAC, which was significantly lower than for resectable PAC (43.6%) (p = 0.004) but significantly higher than for unresectable PAC (0.0%) (p < 0.001). R0 rate was significantly lower in patients with unresectable PAC according to 2020 NCCN Guidelines (10.7%, 3/28) than in those with unresectable PAC according to the previous version (31.7%, 20/63) (p = 0.038). In resectable PAC, tumor size ≥ 3 cm (p = 0.03) and abutment to portal vein (PV) (p = 0.04) were independently associated with margin-positive resection.

CONCLUSIONS

The current NCCN Guidelines are useful for stratifying patients according to prognosis and perform better in R0 prediction in unresectable PAC than the previous version. Larger tumor size and abutment to PV were associated with margin-positive resection in patients with resectable PAC.

KEY POINTS

• The updated 2020 NCCN Guidelines were useful for stratifying patients according to prognosis. • The updated 2020 NCCN Guidelines performed better in the prediction of margin-positive resection in unresectable cases than the previous version. • Tumor size ≥ 3 cm and abutment to the portal vein were associated with margin-positive resection in patients with resectable pancreatic adenocarcinoma.

MAPLE-PD trial (Mesenteric Approach vs. Conventional Approach for Pancreatic Cancer during Pancreaticoduodenectomy): study protocol for a multicenter randomized controlled trial of 354 patients with pancreatic ductal adenocarcinoma

Background

The mesenteric approach is an artery-first approach to pancreaticoduodenectomy for pancreatic cancer, which starts with the dissection of connective tissues around the superior mesenteric artery. The procedure aims for early confirmation of resectability by checking the surgical margin around the superior mesenteric artery first during the operation. It also aims to decrease intraoperative blood loss by early ligation of the inferior pancreaticoduodenal artery and to increase R0 rate by complete clearance of the lymph nodes around the superior mesenteric artery and pancreatic head plexus II, the most favorable positive margin site for pancreatic ductal adenocarcinoma. Furthermore, it aims to avoid the spread of cancer cells during operation (nontouch isolation technique). The MAPLE-PD (Mesenteric Approach vs. Conventional Approach for Pancreatic Cancer during Pancreaticoduodenectomy) trial investigates whether the mesenteric approach can prolong the survival of patients with pancreatic ductal adenocarcinoma who undergo pancreaticoduodenectomy compared with the conventional approach.

Methods/design

The MAPLE-PD trial is a Japanese multicenter randomized controlled trial that compares the surgical outcomes between the mesenteric and conventional approaches to pancreaticoduodenectomy. Patients with pancreatic ductal adenocarcinoma scheduled to undergo pancreaticoduodenectomy are randomized before operation to either a conventional approach (arm A) or a mesenteric approach (arm B). In arm A, the operation starts with Kocher’s maneuver. At the final step of the removal procedure, the connective tissues around the superior mesenteric artery are dissected. In arm B, the operation starts with dissection of the connective tissues around the superior mesenteric artery and ends with Kocher’s maneuver. In total, 354 patients from 15 Japanese high-volume centers will be randomized. The primary endpoint is overall survival by intention-to-treat analysis. Secondary endpoints include intraoperative blood loss, R0 rate, and recurrence-free survival.

Discussion

If the MAPLE-PD trial shows the oncological benefits of the mesenteric approach for patients with pancreatic ductal adenocarcinoma, this procedure may become a standard approach to pancreaticoduodenectomy.

Trial registration

ClinicalTrials.gov, NCT03317886. Registered on 23 October 2017.

University Hospital Medical Information Network Clinical Trials Registry, UMIN000029615. Registered on 15 January 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-3002-z) contains supplementary material, which is available to authorized users.

Management of Borderline Resectable Pancreatic Cancer

With the rapid development of imaging modalities and surgical techniques, the clinical entity representing tumors that are intermediate between resectable and unresectable pancreatic adenocarcinoma has been identified has been termed "borderline resectable" (BR). These tumors are generally amenable for resection but portend an increased risk for positive margins after surgery and commonly necessitate vascular resection and reconstruction. Although there is a lack of consensus regarding the appropriate definition of what constitutes a BR pancreatic tumor, it has been demonstrated that this intermediate category carries a particular prognosis that is in between resectable and unresectable disease. In order to downstage the tumor and increase the probability of clear surgical margins, neoadjuvant therapy is being increasingly utilized and studied. There is a lack of high-level evidence to establish the optimal treatment regimen for BR tumors. When resection with negative margins is achieved after neoadjuvant therapy, the prognosis for BR tumors approaches and even exceeds that for resectable disease. This review presents the current definitions, different treatment approaches, and the clinical outcomes of BR pancreatic cancer.

Clinical significance of defining borderline resectable pancreatic cancer

Since the introduction of the concept of borderline resectable pancreatic cancer (BRPC), various definitions of this disease entity have been suggested. However, there are several obstacles in defining this disease category. The current diagnostic criteria of BRPC mainly focuses on its expanded 'technical resectability'; however, they are difficult to interpret because of their ambiguity using potential subjective or arbitrary terminology, In addition, limitations in current imaging technology and a lack of evidence in radiological-pathological-clinical correlation make it difficult to refine the criteria. On the other hand, neoadjuvant treatment is usually applied to increase the R0 resection rate of BRPC focusing on the 'oncological curability'. However, evidence is needed concerning the effect of neoadjuvant treatment by quality-controlled prospective randomized clinical trials based on a standardized radiologic and pathologic reporting system. In conclusion, there are two aspects in the current concept of BRPC, which are technical resectability and oncological curability. Although the recent evolution of surgical techniques is expanding the scope of technical resectability, it should not be overlooked that the disease entity must be defined based on the evidence of oncological curability.

Mesenteric approach during pancreaticoduodenectomy for pancreatic ductal adenocarcinoma

Mesenteric approach is an artery‐first approach during pancreaticoduodenectomy (PD). In the present study, we evaluated clinical and oncological benefits of this procedure for pancreatic ductal adenocarcinoma (PDAC) of the pancreas head. Between 2000 and 2015, 237 consecutive PDAC patients underwent PD. Among them, 72 experienced the mesenteric approach (mesenteric group) and 165 the conventional approach (conventional group). A matched‐pairs group consisted of 116 patients (58 patients in each group) matched for age, gender, resectability status, and neoadjuvant therapy. Surgical and oncological outcomes were compared between the two groups in unmatched‐ and matched‐pair analyses. Intraoperative blood loss was lower in the mesenteric group than in the conventional group in both resectable PDAC (R‐PDAC) and borderline resectable PDAC (BR‐PDAC) on unmatched‐ and matched‐pairs analyses (R‐PDAC, unmatched: 312.5 vs 510 mL, P=.008; matched: 312.5 vs 501.5 mL, P=.023; BR‐PDAC, unmatched: 507.5 vs 935 mL, P<.001; matched: 507.5 vs 920 mL, P=.003). Negative surgical margins (R0) and overall survival (OS) rates in the mesenteric group were better in R‐PDAC patients (R0 rates, unmatched: 100% vs 87.7%, P=.044; matched: 100% vs 86.7%, P=.045; OS, unmatched: P=.008, matched: P=.021), although there were no significant differences in BR‐PDAC patients. Mesenteric approach might reduce blood loss by early ligation of the vessels to the pancreatic head. Furthermore, it might increase R0 rate, leading to improvement of survival for R‐PDAC patients. However, R0 and survival rates could not be improved only by the mesenteric approach for BR‐PDAC patients. Therefore, effective multidisciplinary treatment is essential to improve survival in BR‐PDAC patients.

Superior mesenteric-portal vein resection during laparoscopic pancreatoduodenectomy

BACKGROUND

Laparoscopic pancreatoduodenectomy (LPD) with concomitant resection of major portal vessels has recently emerged as feasible and safe, with similar morbidity and mortality as well as oncologic outcome compared with patients undergoing open PD with major vascular resection.

MATERIALS AND METHODS

Of a consecutive series of 133 LPD, eight patients underwent concomitant superior mesenteric vein/portal vein (SMV/PV) resection and reconstruction with the intent of achieving a R0 resection.

RESULTS

Four of these eight patients had tangential resection followed by lateral wall repair with Prolene 4.0. One patient had tangential resection with patch reconstruction. Three patients had circular venous resection: One had end-to-end primary venous reconstruction, and two patients had a prosthetic vascular graft interposition. There was no operative mortality. The SMV/PV was patent in all patients postoperatively on ultrasound Doppler or CT scans. Two patients (who underwent circular venous resection) had postoperative complications. One 77-year-old patient with preexisting cardiovascular disease died of heart failure on postoperative day 2, while another (undergoing prosthetic graft reconstruction) had postoperative bilioenteric anastomotic dehiscence and underwent immediate re-laparoscopy for repair.

CONCLUSIONS

In our experience, LPD with concomitant major venous resection is feasible even in cases of longitudinal venous invasion. Further studies are needed to evaluate the role of laparoscopy in borderline pancreatic cancer.

Concomitant major vessel resection in pancreatic adenocarcinoma

Increasing evidence has contraindicated extended radical dissection of pancreatic adenocarcinoma (PC). With the recent improvement of perioperative management techniques and multimodal treatment strategy for PC, concomitant major vessel resection and reconstruction has thus been aggressively attempted in association with comparatively better pathologically negative surgical margins and postoperative survival. We have discussed the clinical relevance of concomitant major vessel resection mainly focusing on indications for such resection with borderline resectable tumor associated with chemoradiotherapy, distal pancreatectomy with en bloc celiac axis resection for pancreatic body and tail cancer, and adjuvant surgery for initially unresectable pancreatic cancer.