Authors' reply: Resection margin involvement and tumour origin in pancreatic head cancer (Br J Surg 2012; 99: 1036-1049)

Does the Volume-Outcome Association in Pancreas Cancer Surgery Justify Regionalization of Care? A Review of Current Controversies

INTRODUCTION

Increasing hospital or surgeon volume is associated with improved outcomes among patients with pancreatic cancer. Promotion of regionalized care is based on this volume-outcome association. However, other research has exposed nuances and complexities inherent to this association that should be considered when promoting regionalized care models. We herein provide a critical review of the literature on the volume-outcome association and a discussion of areas of ongoing controversy.

METHODS

A PubMed literature search was conducted for the years 1995-2020. Peer reviewed original research studies were selected for critical review based on study design, potential to draw meaningful conclusions from the data, and discussion of current knowledge gaps.

RESULTS

Based on the cumulative published literature, hospital/surgeon volume and patient mortality are inversely related. However, it remains unclear whether volume is a proxy for other more causative variables inherent in high-volume centers. Interpretation of the volume-outcome association is made more difficult to interpret due to the large variation in the definition of high volume, difficulty in isolating the individual impact of surgeon versus hospital volume, challenges in quantifying health system processes related to volume, and the fact that some low-volume centers consistently achieve excellent clinical results. Implementation of true regionalized care models has been rare, likely reflecting both health system and patient level challenges.

CONCLUSION

The volume-outcome association has been consistently demonstrated to be important to the care of patients with pancreas cancer. The underlying mechanism of this association to explain the overall benefit is likely multifactorial. Better understanding of what drives the volume-outcome association may increase access to optimized care for a broader range of hospital systems and patients.

[Standardized diagnosis of pancreatic head carcinoma]

Most pancreatic ductal adenocarcinomas are localized in the pancreatic head. Due to the complex anatomic relationships with the surrounding organs and vascular structures in the retroperitoneal space and to the presence of numerous transection margins and dissection planes, pancreatic head resections belong to the most complex specimens concerning grossing and sampling for histopathologic analysis.Here we discuss current guidelines for standardized grossing and reporting of pancreatic cancer, with special reference to the assessment of the resection margin status. The importance of standardized reporting for the sake of completeness, comprehensibility, comparability, and quality control as well as for the integration of pathology reports in interdisciplinary digital workflows and artificial intelligence applications will be emphasized.

The role of intraoperative radiation therapy in resectable pancreatic cancer: a systematic review and meta-analysis

PURPOSE

Several studies investigating the role of intraoperative radiotherapy (IORT) in the treatment of resectable pancreatic cancer (PC) have been published; however, their results remain inconsistent. By conducting a systematic review and meta-analysis, this study aimed to compare clinical outcomes in patients with resectable PC who underwent surgery with or without IORT.

METHODS AND MATERIALS

The MEDLINE/PubMed, EMBASE, and Cochrane Library databases were searched to identify relevant studies published up to February 28, 2019. The main outcome measures included median survival time (MST), local recurrence (LR), postoperative complications, and operation-related mortality. Pooled effect estimates were obtained by performing a random-effects meta-analysis.

RESULTS

A total of 1095 studies were screened for inclusion, of which 15 studies with 834 patients were included in the meta-analysis. Overall, 401 patients underwent pancreatic resection with IORT and 433 underwent surgery without IORT. The pooled analysis revealed that IORT group experienced favorable overall survival (median survival rate [MSR], 1.20; 95% confidence interval [CI], 1.06-1.37, P = 0.005), compared with patients who did not receive IORT. Additionally, the pooled data showed a significantly reduced LR rate in the IORT group compared with that in the non-IORT group (relative risk [RR], 0.70; 95% CI, 0.51-0.97, P = 0.03). The incidences of postoperative complications (RR, 0.95; 95% CI, 0.73-1.23) and operation-related mortality (RR, 1.07; 95% CI, 0.44-2.63) were similar between the IORT and non-IORT groups.

CONCLUSION

IORT significantly improved locoregional control and overall survival in patients with resectable PC, without increasing postoperative complications and operation-related mortality rates.

A systematic review and network meta-analysis of different surgical approaches for pancreaticoduodenectomy

BACKGROUND

Minimally invasive pancreaticoduodenectomy (MIPD) is a demanding surgical procedure, thus explaining its slow expansion and limited popularity amongst Hepato-Pancreatico-Biliary (HPB) surgeons. However, three main advantages of robotic assisted pancreaticoduodenectomy (PD) including improved dexterity, 3D vision less surgical fatigue, may overcome some of the hurdles and ultimately lead to a wider adoption. This systematic review and network meta-analysis aims to evaluate the current literature on open and MIPD.

METHODS

A systematic literature search was conducted for studies reporting robotic, laparoscopic and open surgery for PD. Network meta-analysis of intraoperative (operating time, blood loss, transfusion rate), postoperative (overall and major complications, pancreatic fistula, delayed gastric emptying, length of hospital stay) and oncological outcomes (R0 resection, lymphadenectomy) were performed.

RESULTS

Sixty-one studies including 62,529 patients were included in the network meta-analysis, of which 3% (n = 2131) were totally robotic (TR) and 10% (n = 6514) were totally laparoscopic (TL). There were no significant differences between surgical techniques for major complications, overall and grade B/C fistula, biliary leak, mortality and R0 resections. Transfusion rates were significantly lower in TR compared to TL and open. Operative time for TR was longer compared with open and TL. Both TL and TR were associated with significantly lower rates of wound infections, pulmonary complications, shorter length of stay and higher lymph nodes examined when compared to open. TR was associated with significantly lower conversion rates than TL.

CONCLUSION

In summary, this network meta-analysis highlights the variability in techniques within MIPD and compares other variations to the conventional open PD. Current evidence appears to demonstrate MIPD, both laparoscopic and robotic techniques are associated with improved rates of surgical site infections, pulmonary complications, and a shorter hospital stay, with no compromise in oncological outcomes for cancer resections.

Whipple made simple for surgical pathologists: orientation, dissection, and sampling of pancreaticoduodenectomy specimens for a more practical and accurate evaluation of pancreatic, distal common bile duct, and ampullary tumors

Pancreaticoduodenectomy (PD) specimens present a challenge for surgical pathologists because of the relative rarity of these specimens, combined with the anatomic complexity. Here, we describe our experience on the orientation, dissection, and sampling of PD specimens for a more practical and accurate evaluation of pancreatic, distal common bile duct (CBD), and ampullary tumors. For orientation of PDs, identification of the "trapezoid," created by the vascular bed at the center, the pancreatic neck margin on the left, and the uncinate margin on the right, is of outmost importance in finding all the pertinent margins of the specimen including the CBD, which is located at the upper right edge of this trapezoid. After orientation, all the margins can be sampled. We submit the uncinate margin entirely as a perpendicular inked margin because this adipose tissue-rich area often reveals subtle satellite carcinomas that are grossly invisible, and, with this approach, the number of R1 resections has doubled in our experience. Then, to ensure proper identification of all lymph nodes (LNs), we utilize the orange-peeling approach, in which the soft tissue surrounding the pancreatic head is shaved off in 7 arbitrarily defined regions, which also serve as shaved samples of the so-called "peripancreatic soft tissue" that defines pT3 in the current American Joint Committee on Cancer TNM. With this approach, our LN count increased from 6 to 14 and LN positivity rate from 50% to 73%. In addition, in 90% of pancreatic ductal adenocarcinomas there are grossly undetected microfoci of carcinoma. For determination of the primary site and the extent of the tumor, we believe bisectioning of the pancreatic head, instead of axial (transverse) slicing, is the most revealing approach. In addition, documentation of the findings in the duodenal surface of the ampulla is crucial for ampullary carcinomas and their recent site-specific categorization into 4 categories. Therefore, we probe both the CBD and the pancreatic duct from distal to the ampulla and cut the pancreatic head to the ampulla at a plane that goes through both ducts. Then, we sample the bisected pancreatic head depending on the findings of the case. For example, for proper staging of ampullary carcinomas, it is imperative to take the sections perpendicular to the duodenal serosa at the "groove" area, as ampullary carcinomas often extend to this region. Amputative (axial) sectioning of the ampulla, although good for documentation of the peri-Oddi spread of the intra-ampullary tumors, unfortunately disallows documentation of mucosal spread of the papilla of Vater tumors (those arising from the edge of the ampulla, where the ducts transition to duodenal mucosa and extending) into the neighboring duodenum. Axial sectioning also often fails to document tumor spread to the "groove" area. In conclusion, knowledge of the gross characteristics of the anatomic hallmarks is essential for proper dissection of PD specimens. The approach described above allows practical and accurate documentation and staging of pancreas, distal CBD, and ampullary cancers.