Retroperitoneal margin of the pancreaticoduodenectomy specimen: anatomic mapping for the surgical pathologist

Towards a More Standardized Approach to Pathologic Reporting of Pancreatoduodenectomy Specimens for Pancreatic Ductal Adenocarcinoma: Cross-continental and Cross-specialty Survey From the Pancreatobiliary Pathology Society Grossing Working Group

In recent literature and international meetings held, it has become clear that there are significant differences regarding the definition of what constitutes as margins and how best to document the pathologic findings in pancreatic ductal adenocarcinoma. To capture the current practice, Pancreatobiliary Pathology Society (PBPS) Grossing Working Group conducted an international multispecialty survey encompassing 25 statements, regarding pathologic examination and reporting of pancreatic ductal adenocarcinoma, particularly in pancreatoduodenectomy specimens. The survey results highlighted several discordances; however, consensus/high concordance was reached for the following: (1) the pancreatic neck margin should be entirely submitted en face, and if tumor on the slide, then it is considered equivalent to R1; (2) uncinate margin should be submitted entirely and perpendicularly sectioned, and tumor distance from the uncinate margin should be reported; (3) all other surfaces (including vascular groove, posterior surface, and anterior surface) should be examined and documented; (4) carcinoma involving separately submitted celiac axis specimen should be staged as pT4. Although no consensus was achieved regarding what constitutes R1 versus R0, most participants agreed that ink on tumor or at and within 1 mm to the tumor is equivalent to R1 only in areas designated as a margin, not surface. In conclusion, this survey raises the awareness of the discordances and serves as a starting point towards further standardization of the pancreatoduodenectomy grossing and reporting protocols.

Exosomal microRNA in Pancreatic Cancer Diagnosis, Prognosis, and Treatment: From Bench to Bedside

Pancreatic cancer is the fourth leading cause of cancer death among men and women in the United States, and pancreatic ductal adenocarcinoma (PDAC) accounts for more than 90% of pancreatic cancer cases. PDAC is one of the most lethal gastrointestinal malignancies with an overall five-year survival rate of ~10%. Developing effective therapeutic strategies against pancreatic cancer is a great challenge. Novel diagnostic, prognostic, and therapeutic strategies are an immediate necessity to increase the survival of pancreatic cancer patients. So far, studies have demonstrated microRNAs (miRNAs) as sensitive biomarkers because of their significant correlation with disease development and metastasis. The miRNAs have been shown to be more stable inside membrane-bound vesicles in the extracellular environment called exosomes. Varieties of miRNAs are released into the body fluids via exosomes depending on the normal physiological or pathological conditions of the body. In this review, we discuss the recent findings on the diagnostic, prognostic, and therapeutic roles of exosomal miRNAs in pancreatic cancer.

Predictive factors for long-term survival after surgery for pancreatic ductal adenocarcinoma: Making a case for standardized reporting of the resection margin using certified cancer center data

Factors for overall survival after pancreatic ductal adenocarcinoma (PDAC) seem to be nodal status, chemotherapy administration, UICC staging, and resection margin. However, there is no consensus on the definition for tumor free resection margin. Therefore, univariate OS as well as multivariate long-term survival using cancer center data was analyzed with regards to two different resection margin definitions. Ninety-five patients met inclusion criteria (pancreatic head PDAC, R0/R1, no 30 days mortality). OS was analyzed in univariate analysis with respect to R-status, CRM (circumferential resection margin; positive: ≤1mm; negative: >1mm), nodal status, and chemotherapy administration. Long-term survival >36 months was modelled using multivariate logistic regression instead of Cox regression because the distribution function of the dependent data violated the requirements for the application of this test. Significant differences in OS were found regarding the R status (Median OS and 95%CI for R0: 29.8 months, 22.3–37.4; R1: 15.9 months, 9.2–22.7; p = 0.005), nodal status (pN0 = 34.7, 10.4–59.0; pN1 = 17.1, 11.5–22.8; p = 0.003), and chemotherapy (with CTx: 26.7, 20.4–33.0; without CTx: 9.7, 5.2–14.1; p < .001). OS according to CRM status differed on a clinically relevant level by about 12 months (CRM positive: 17.2 months, 11.5–23.0; CRM negative: 29.8 months, 18.6–41.1; p = 0.126). A multivariate model containing chemotherapy, nodal status, and CRM explained long-term survival (p = 0.008; correct prediction >70%). Chemotherapy, nodal status and resection margin according to UICC R status are univariate factors for OS after PDAC. In contrast, long-term survival seems to depend on wider resection margins than those used in UICC R classification. Therefore, standardized histopathological reporting (including resection margin size) should be agreed upon.

Impact of resection margin status on recurrence and survival in pancreatic cancer surgery

BACKGROUND

The prognosis of patients with pancreatic ductal adenocarcinoma (PDAC) is poor and selection of patients for surgery is challenging. This study examined the impact of a positive resection margin (R1) on locoregional recurrence (LRR) and overall survival (OS); and also aimed to identified tumour characteristics and/or technical factors associated with a positive resection margin in patients with PDAC.

METHODS

Patients scheduled for pancreatic resection for PDAC between 2006 and 2016 were identified from an institutional database. The effect of resection margin status, patient characteristics and tumour characteristics on LRR, distant metastasis and OS was assessed.

RESULTS

A total of 322 patients underwent pancreatectomy for PDAC. A positive resection (R1) margin was found in 129 patients (40·1 per cent); this was associated with decreased OS compared with that in patients with an R0 margin (median 15 (95 per cent c.i. 13 to 17) versus 22 months; P < 0·001). R1 status was associated with reduced time to LRR (median 16 versus 36 (not estimated, n.e.) months; P = 0·002). Disease recurrence patterns were similar in the R1 and R0 groups. Risk factors for early recurrence were tumour stage, positive lymph nodes (N1) and perineural invasion. Among 100 patients with N0 disease, R1 status was associated with shorter OS compared with R0 resection (median 17 (10 to 24) versus 45 (n.e.) months; P = 0·002), whereas R status was not related to OS in 222 patients with N1 disease (median 14 (12 to 16) versus 17 (15 to 19) months after R1 and R0 resection respectively; P = 0·068).

CONCLUSION

Although pancreatic resection with a positive margin was associated with poor survival and early recurrence, particularly in patients with N1 disease, disease recurrence patterns were similar between R1 and R0 groups.

Prediction of Recurrence With KRAS Mutational Burden Using Ultrasensitive Digital Polymerase Chain Reaction of Radial Resection Margin of Resected Pancreatic Ductal Adenocarcinoma

OBJECTIVE

Although complete surgical resection is the only curative method for pancreatic cancer, the radial resection margins of pylorus-preserving pancreaticoduodenectomy specimens might be underevaluated.

METHODS

KRAS mutation was assessed with droplet digital polymerase chain reaction on cells collected from the radial resection margins of 81 patients, and the results were compared with those of conventional pathologic resection margin (pRM) evaluation.

RESULTS

KRAS mutation was detected in 76 patients (94%), and molecular resection margin (mRM) positivity defined by a KRAS mutation rate of 4.19% or greater was observed in 18 patients (22%). Patients with mRM-positive had significantly worse recurrence-free survival (RFS) than those with mRM-negative in entire groups (P = 0.008) and in subgroups without chemotherapy or radiation therapy (all, P < 0.001). When combined pRMs-mRMs were evaluated, patients with combined pRM-mRM-positive (either pRM- or mRM-positive) had significantly worse RFS than those with combined resection margin-negative (both pRM and mRM negative) by univariate (P = 0.002) and multivariate (P = 0.03) analyses.

CONCLUSIONS

KRAS mutational analysis with ultrasensitive droplet digital polymerase chain reaction of the radial resection margin in pancreatic cancer patients who underwent pylorus-preserving pancreaticoduodenectomy can provide more accurate information on RFS by using alone or in combination with conventional pRM evaluation, especially in patients without chemotherapy or radiation therapy.

Ameliorating efficacy of eugenol against metanil yellow induced toxicity in albino Wistar rats

Metanil yellow, an azo dye, is a non-permitted synthetic food colour used extensively in India and other developing countries as food additive. Present communication reports the toxic effects of metanil yellow on hepatic and kidney tissues and its amelioration by eugenol, vitamin E and vitamin C. Oral administration of metanil yellow in albino Wistar rats for 28 days caused elevation in serum enzymes (glutamate oxaloacetate transaminase, gluatamate pyruvate transaminase, alkaline phosphatase), and total bilirubin along with decline in albumin and total protein levels. At tissue level, activities of oxidative stress markers viz., superoxide dismutase, catalase and reduced glutathione in liver and kidney were reduced to about half while malondialdehyde level increased significantly under the influence of metanil yellow. Co-administration of eugenol/vitamin E/vitamin C in metanil yellow intoxicated rats exhibited considerable restoration of oxidative stress as well as hepatic and renal function markers in serum and tissues. The study revealed that eugenol has antioxidant, hepatoprotective and renoprotective activities.

Tumour origin and R1 rates in pancreatic resections: towards consilience in pathology reporting

To evaluate differences in the R1 rates of ampullary (AC), pancreatic (PC), and distal bile duct (DBD) cancers in pancreatoduodenectomies (PD) using standardised pathology assessment. Data of PD (2010-2011) analysed in accordance with the Royal College of Pathologists (UK) protocol, were retrieved. Clinicopathologic features, including frequency, topography, and mode of margin involvement in AC (n = 87), PC (n = 18), and DBD (n = 5) cancers were evaluated. The R1 rate was 7%, 67%, and 20% in the AC, PC, and DBD cancers (p < 0.001). Within the PC cohort, R1 rate was heterogeneous (chemo-naïve, 77%; post-neoadjuvant, 40%). Commonest involved margins were as follows: posterior in overall PD (35%), AC (43%), overall PC (33%), and post-neoadjuvant PC (100%); superior mesenteric artery margin in chemo-naïve PC (38%) and common bile duct margin in DBD (100%) cancers. In AC, majority (66%) of R1 were signet ring cell type. Indirect margin involvement due to tumour within lymph node, perineural sheath or lymphovascular space was observed in 26% cases, and altered R1 rate in AC, PC, and DBD cohorts by 1%, 12%, and 0%, respectively. Although not statistically significant, patients with R1 had lower disease-free survival than those with R0 (mean, 25.4 months versus 44.4 months). Tumour origin impacts R1 data in PD necessitating its accurate classification by pathologists. Indirect involvement, histology, and neoadjuvant therapy influence the R1 rate, albeit in a minority of cases. Generating cogent R1 data based on standardised pathology reporting is the foremost need of the hour.

Mesopancreas is a misnomer: time to correct the nomenclature

Focused pathological attention to tumor invasion of the retroperitoneal resection margin after pancreaticoduodenectomy for cancer of head of the pancreas led to the knowledge of strong tendency of cancer cells to infiltrate into the retropancreatic tissue and to spread along the peripancreatic neural plexuses as the cause of local recurrence. The term 'mesopancreas' was coined to describe perineural lymphatic layer located dorsally to the pancreas and it was suggested that its complete resection will minimize loco-regional recurrence and improve outcome. This catchy title and concept attracted the attention of surgeons and "total meso-pancreas excision" was introduced by 'artery first' or 'posterior first' surgical techniques to ensure 'en-bloc' extended resection of retropancreatic lymphatics. However, mesopancreas is a misnomer and cannot be called a 'true' mesentery as it does not have a fascial envelope attaching the pancreas to the posterior wall of the abdomen and does not contain 'all' its blood vessels and 'all' its primary draining lymphatics and lymph nodes. Japan Pancreas Society's description of pancreatic head plexus II is anatomically consistent with 'mesopancreas' and it should be renamed as such. This nomenclature clearly illustrates its exact anatomical location and surgical relevance; and stands up to necessary rigorous scientific scrutiny.

The importance of surgical margins in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with a grim prognosis. Surgical resection offers the best chance for long-term survival, yet recurrence rates are high and outcomes are poor. The influence of margin status in PDAC is controversial, as conflicting data have been plagued by a lack of standardization in margin definitions, pathologic analysis, and reporting. Despite recent efforts, international consensus is still needed for this disease.

Meta-analysis of radical resection rates and margin assessment in pancreatic cancer

BACKGROUND

R0 resection rates (complete tumour removal with negative resection margins) in pancreatic cancer are 70-80 per cent when a 0-mm margin is used, declining to 15-24 per cent with a 1-mm margin. This review evaluated the R0 resection rates according to different margin definitions and techniques.

METHODS

Three databases (MEDLINE from 1946, PubMed from 1946 and Embase from 1949) were searched to mid-October 2014. The search terms included 'pancreatectomy OR pancreaticoduodenectomy' and 'margin'. A meta-analysis was performed with studies in three groups: group 1, axial slicing technique (minimum 1-mm margin); group 2, other slicing techniques (minimum 1-mm margin); and group 3, studies with minimum 0-mm margin.

RESULTS

The R0 rates were 29 (95 per cent c.i. 26 to 32) per cent in group 1 (8 studies; 882 patients) and 49 (47 to 52) per cent in group 2 (6 studies; 1568 patients). The combined R0 rate (groups 1 and 2) was 41 (40 to 43) per cent. The R0 rate in group 3 (7 studies; 1926 patients) with a 0-mm margin was 72 (70 to 74) per cent The survival hazard ratios (R1 resection/R0 resection) revealed a reduction in the risk of death of at least 22 per cent in group 1, 12 per cent in group 2 and 23 per cent in group 3 with an R0 compared with an R1 resection. Local recurrence occurred more frequently with an R1 resection in most studies.

CONCLUSION

Margin clearance definitions affect R0 resection rates in pancreatic cancer surgery. This review collates individual studies providing an estimate of achievable R0 rates, creating a benchmark for future trials.

Pathology handling of pancreatoduodenectomy specimens: Approaches and controversies

Pancreatic cancer, with a 5% 5-year survival rate, is the fourth leading cause of cancer death in Western countries. Unfortunately, only 20% of all patients benefit from surgical treatment. The need to prolong survival has prompted pathologists to develop improved protocols to evaluate pancreatic specimens and their surgical margins. Hopefully, the new protocols will provide clinicians with more powerful prognostic indicators and accurate information to guide their therapeutic decisions. Despite the availability of several guidelines for the handling and pathology reporting of duodenopancreatectomy specimens and their continual updating by expert pathologists, there is no consensus on basic issues such as surgical margins or the definition of incomplete excision (R1) of pancreatic ductal adenocarcinoma. This article reviews the problems and controversies that dealing with duodenopancreatectomy specimens pose to pathologists, the various terms used to define resection margins or infiltration, and reports. After reviewing the literature, including previous guidelines and based on our own experience, we present our protocol for the pathology handling of duodenopancreatectomy specimens.

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.

Clinical observation on the efficacy of CyberKnife for primary or metastatic retroperitoneal tumours

The aim of the paper is to evaluate the efficacy of CyberKnife® for the treatment of primary or metastatic retroperitoneal tumours. Twenty-eight patients were treated. The prescription isodose line (median, 78%; range, 70-84%) covered the planning target volume at a total dose of 2000-6000 cGy (median, 4500 cGy) and a biologically effective dose of 3750-10,080 cGy (median, 7680 cGy) in 2-10 fractions (median, five fractions). The results showed that the complete response, partial response, stable disease, and progressive disease rates were 43% (12/28), 36% (10/28), 18% (5/28), and 4% (1/28) respectively. The overall response rate was 96%. The 1-, 2- and 3-year local control rates were 92%, 86%, and 86% respectively. The 1-, 2- and 3-year overall survival rates were 60%, 49%, and 49% respectively. No significant difference was found between local progression-free survival and overall survival. Moreover, if a patient only had metastases in the retroperitoneum and local control was effective, there was no significant difference between local progression-free survival and overall progression-free survival. In conclusion, CyberKnife treatment for retroperitoneal tumours resulted in high response rates with minimal side effects. All radiation-induced side effects were well tolerated.

An anatomical-based mapping analysis of the pancreaticoduodenectomy retroperitoneal margin highlights the urgent need for standardized assessment

OBJECTIVES

Assessment of a pancreaticoduodenectomy specimen by pathologists requires specialized knowledge of anatomy. Standardized assessment, description and documentation of the retroperitoneal margin are crucial for the accurate interpretation of studies evaluating adjuvant therapy for pancreatic cancer patients.

METHODS

Twenty-five patients who underwent a pancreaticoduodenectomy for pancreatic adenocarcinomas had their pathological specimens examined prospectively, using an anatomical-based mapping approach. All margins, including the bile duct, pancreatic neck, superior mesenteric artery, superior mesenteric vein and posterior surface of the uncinate process, were microscopically examined in their entirety. The assessment of an R1 margin in terms of distance was assessed in two ways: first defining it as a tumour at the margin or secondary as tumour within 1 mm (1 mm rule).

RESULTS

If the existing College of American Pathologists recommendations were applied (assessing only the bile duct, pancreatic neck and superior mesenteric artery margins), a R1 status would be achieved in only 9 of 25 patients. Extending the examination by assessment and reporting of the entire retroperitoneal resection margin, including the Superior Mesenteric Vein margin and the Posterior surface of the uncinate process margin, increased the number of patients with a R1 resection to 14 out of 25. Applying the 1-mm rule further increased the number of patient with a R1 resection to 20 of 25 patients.

CONCLUSIONS

The above findings illustrate that different approaches to the assessment and reporting of the retroperitoneal margin can change the results and adversely affect the final statistics used in pancreatic cancer studies and clinical trials.

Resection margin involvement and tumour origin in pancreatic head cancer

BACKGROUND

Assessment of the origin of adenocarcinoma in pancreatoduodenectomy specimens (pancreatic, ampullary or biliary) and resection margin status is not performed in a consistent manner in different centres. The aim of this review was to identify the impact of such variations on patient outcome.

METHODS

A systematic literature search for articles on pancreatic, ampullary, distal bile duct and periampullary cancer was performed, with special attention to data on resection margin status, pathological examination and outcome.

RESULTS

The frequent reclassification of tumour origin following slide review, and the wide variation in published incidence of pancreatic (33-89 per cent), ampullary (5-42 per cent) and distal bile duct (5-38 per cent) cancers indicate that the histopathological distinction between the three cancer groups is less accurate than generally believed. Recent studies have shown that the wide range of rates of microscopic margin involvement (R1) in pancreatoduodenectomy specimens (18-85, 0-27 and 0-72 per cent respectively for pancreatic, ampullary and distal bile duct cancers) is mainly caused by differences in pathological assessment rather than surgical practice and patient selection. As a consequence of the existing inconsistency in reporting of these data items, the clinical significance of microscopic margin involvement in each of the three cancer groups remains unclear.

CONCLUSION

Inaccurate and inconsistent distinction between pancreatic, ampullary and distal bile duct cancer, combined with inaccuracies in resection margin assessment, results in obfuscation of key clinicopathological data. Specimen dissection technique plays a key role in the quality of the assessment of both tumour origin and margin status. Unless the pathological examination is meticulous and standardized, comparison of results between centres and observations in multicentre trials will remain of limited value.

Preoperative chemoradiation followed by surgical resection for resectable pancreatic cancer: a review of current results

BACKGROUND

There has been an interest in the interdisciplinary and multimodality approach that combines chemotherapy and radiation therapy as a preoperative treatment for patients with resectable pancreatic cancer.

METHODS

Literature search of databases (Medline and PubMed) to identify published studies of preoperative chemoradiation for resectable pancreatic cancer (potentially resectable and borderline resectable) was undertaken. Response to treatment and survival outcomes was examined as endpoints of this review.

RESULTS

Seventeen studies; eight phase II studies, and nine observational studies, comprising of 977 patients were reviewed. Gemcitabine-based chemotherapy with radiotherapy was the most common preoperative regimen. Following preoperative treatment, pancreatic surgical resection was performed in 35-100% (median=61%) of patients after a range of 6-32 weeks (median=7 weeks). Rate of pathological response was complete in 5-15% of patients, partial in 33-60% and minimal in 38-42%. The median overall survival ranged from 12 months to 40 months (median=25 months) with a 5-year overall survival rate ranging between 8% and 36% (median=28%). Patients who underwent chemoradiation but did not undergo surgery survived a median period of 7-11 months (median=9 months).

CONCLUSION

Preoperative gemcitabine-based chemoradiation followed by restaging and surgical evaluation for pancreatic resection may identify a sub-population of patients with resectable disease who would benefit the most from surgery. Investigation of this schema of preoperative therapy in a randomized setting of resectable pancreatic cancer is warranted.

Peripancreatic fat invasion is an independent predictor of poor outcome following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma

BACKGROUND

Following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma (PDAC), identification of peripancreatic fat tumor invasion promotes a tumor to stage T3. We sought to understand better the impact of histological peripancreatic fat invasion on prognosis and site of recurrence in a cohort of patients with PDAC.

METHODS

We analyzed the patient demographics, outcome, and recurrence data that had been prospectively collected in 189 consecutive PDAC undergoing potentially curative pancreaticoduodenectomy between 1996 and 2009. Pathological features were reassessed for all patients. Survival outcome was compared using Kaplan-Meier/Cox proportional hazards analysis. The primary site of recurrence was defined as either locoregional or distant metastases.

RESULTS

The median survival of this PDAC cohort was 18.9 months (95% confidence interval (CI) 15.7-22.2). Histological peripancreatic fat invasion was evident in 51 (27%) patients and was associated with lymph node metastases (p = 0.004) and larger tumor size (p = 0.015). The presence of peripancreatic fat invasion was associated with reduced overall survival following resection (12.4 months [95% CI 9.9-15.0]) when compared to those patients with no evidence of fat invasion (22.6 months [95% CI 18.5-26.7]; p < 0.0001). By multivariate survival analysis, independent predictors of overall survival included tumor grade (p = 0.002), lymph node involvement (p = 0.025), resection margin status (p = 0.003), venous invasion (p = 0.045), and peripancreatic fat invasion (p = 0.007). Invasion into the pancreatic fat was significantly associated with the primary site of recurrence being locoregional failure (p = 0.002).

CONCLUSIONS

Peripancreatic fat invasion was identified as being an independent predictor of poor outcome following pancreaticoduodenectomy for PDAC. Additionally, the presence of peripancreatic fat invasion was associated with locoregional disease as the primary site of recurrence. This may have implications for the staging of PDAC and potentially require incorporation into future staging systems to improve outcome stratification.

Standardization of surgical and pathologic variables is needed in multicenter trials of adjuvant therapy for pancreatic cancer: results from the ACOSOG Z5031 trial

BACKGROUND

Standardization of surgical and pathologic techniques is crucial to the interpretation of studies evaluating adjuvant therapies for pancreatic cancer (PC).

METHODS

To assess the degree to which treatment administered prior to enrollment of patients in trials of adjuvant therapy is quality controlled, the operative and pathology reports of patients in American College of Surgeons Oncology Group (ACOSOG) Z5031-a national trial of chemoradiation following pancreaticoduodenectomy (PD)-were rigorously evaluated. We analyzed variables with the potential to influence staging or outcome.

RESULTS

80 patients reported to have undergone R0 (75%) or R1 (25%) pylorus-preserving (38%) or standard (62%) PD were evaluated. A search for metastases was documented in 96% of cases. The proximity of the tumor to the superior mesenteric vein was reported in 69%; vein resection was required in 9% and lateral venorrhaphy in 14%. The method of dissection along the superior mesenteric artery (SMA) was described in 68%, being ultrasonic dissection (17%), stapler (24%), and clamp and cut (59%). SMA skeletonization was described in 25%, and absence of disease following resection was documented in 24%. The surgeon reported marking the critical SMA margin in 25%; inking was documented in 65% of cases and evaluation of the SMA margin was reported in 47%. A range of 1-49 lymph nodes was evaluated. Only 34% of pathology reports met College of American Pathologists criteria.

CONCLUSIONS

Trials of adjuvant therapy following PD suffer from a lack of standardization and quality control prior to patient enrollment. These data suggest areas for improvement in the design of multidisciplinary treatment protocols.

Positive mobilization margins alone do not influence survival following pancreatico-duodenectomy for pancreatic ductal adenocarcinoma

OBJECTIVE

To determine the prognostic influence of residual tumor at or within 1 mm of the mobilization margins (R1Mobilization) compared with transection margins (R1Transection) following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma (PDAC).

BACKGROUND

The prognostic strength of R1 status increases with frequency of margin positivity and is enhanced by protocol driven pathology reporting. Currently, margins are treated uniformly with tumor at or close to any margin considered of equal prognostic significance. The resection involves a mobilization phase freeing the posterior margin and anterior surface then a transection phase requiring lympho-vascular division forming the medial resection and pancreatic transection margin. The comparative assessment of the relative importance of tumor involvement of these different margins has not previously been investigated.

METHODS

Retrospective analysis of 148 consecutive resections for PDAC from 1996-2007 was performed. The individual (pancreatic transection, medial, posterior, and anterior surface) margins were separately identified and analyzed by a senior pathologist. An R1 resection was defined as microscopic evidence of tumor < or = 1 mm from a resection margin. R1Mobilization tumor extension included both R1Anterior and R1Posterior cases; while R1Transection included pancreatic neck/body transection, R1Medial and adjacent transection margins.

RESULTS

R1 status was confirmed in 109 patients (74%). The medial (46%) and posterior (44%) margins were most commonly involved. R1 status was found to an independent predictor of poor outcome (P < 0.001). R1Mobilization involvement only (n = 48) was associated with a significantly longer median survival of 18.9 months (95% CI, 13.7-24.8) versus 11.1 months (95% CI, 7.1-15.0) for those with R1Transection tumor involvement (n = 61) (P < 0.001). There was no significant difference in the survival of the R1Mobilization compared with R0 group (P = 0.52).

CONCLUSIONS

Following pancreaticoduodenectomy for PDAC, involvement of the transection margins in contrast to mobilization margins defines a group whose outcome is significantly worse. This may impact upon the allocation of adjuvant therapy within the setting of randomized controlled trials.

Redefining resection margin status in pancreatic cancer

Curative resection is crucial to survival in pancreatic cancer; however, despite optimization and standardization of surgical procedures, this is not always achieved. This review highlights that the rates of microscopic margin involvement (R1) vary markedly between studies and, although resection margin status is believed to be a key prognostic factor, the rates of margin involvement and local tumour recurrence or overall survival of pancreatic cancer patients are often incongruent. Recent studies indicate that the discrepancy between margin status and clinical outcome is caused by frequent underreporting of microscopic margin involvement. Lack of standardization of pathological examination, confusing nomenclature and controversy regarding the definition of microscopic margin involvement have resulted in the wide variation of reported R1 rates that precludes meaningful comparison of data and clinicopathological correlation.