Different approaches to assessment of lymph nodes and surgical margin status in patients with ductal adenocarcinoma of the pancreas treated with pancreaticoduodenectomy

The Role of Pathological Method and Clearance Definition for the Evaluation of Margin Status after Pancreatoduodenectomy for Periampullary Cancer. Results of a Multicenter Prospective Randomized Trial

BACKGROUND

There is extreme heterogeneity in the available literature on the determination of R1 resection rate after pancreatoduodenectomy (PD); consequently, its prognostic role is still debated. The aims of this multicenter randomized study were to evaluate the effect of sampling and clearance definition in determining R1 rate after PD for periampullary cancer and to assess the prognostic role of R1 resection.

METHODS

PD specimens were randomized to Leeds Pathology Protocol (LEEPP) (group A) or the conventional method adopted before the study (group B). R1 rate was determined by adopting 0- and 1-mm clearance; the association between R1, local recurrence (LR) and overall survival (OS) was also evaluated.

RESULTS

One-hundred-sixty-eight PD specimens were included. With 0 mm clearance, R1 rate was 26.2% and 20.2% for groups A and B, respectively; with 1 mm, R1 rate was 60.7% and 57.1%, respectively (p > 0.05). Only in group A was R1 found to be a significant prognostic factor: at 0 mm, median OS was 36 and 20 months for R0 and R1, respectively, while at 1 mm, median OS was not reached and 30 months. At multivariate analysis, R1 resection was found to be a significant prognostic factor independent of clearance definition only in the case of the adoption of LEEPP.

CONCLUSIONS

The 1 mm clearance is the most effective factor in determining the R1 rate after PD. However, the pathological method is crucial to accurately evaluate its prognostic role: only R1 resections obtained with the adoption of LEEPP seem to significantly affect prognosis.

Intra-Operative Frozen Section Histology of the Pancreatic Resection Margins and Clinical Outcome of Patients with Adenocarcinoma of the Head of the Pancreas Undergoing Pancreaticoduodenectomy

BACKGROUND The aim of this study was to compare the clinical outcome in patients with pancreatic ductal adenocarcinoma who underwent frozen section and paraffin section histology of the surgical resection margins during pancreaticoduodenectomy. MATERIAL AND METHODS Frozen section and routine paraffin section histopathology were performed using the following categories: R0 (no tumor cells at the surgical resection margin), R1 (tumor cells at, or within 1 mm, of the surgical resection margin), and R2 (tumor seen macroscopically at the surgical resection margin). R1 and R2 patients underwent additional resection to achieve R0. RESULTS Of 346 patients who underwent pancreaticoduodenectomy, frozen section histology showed positive resection margins in 22 patients (9.2%) and paraffin section histology was positive in 20 patients (8.4%). The OS was nine months in frozen section-positive patients and 20 months in frozen section-negative patients (p=0.001). The OS rates were significantly different between the paraffin section-positive and paraffin section-negative patients (11 months vs. 21 months) (p=0.001). Univariate and multivariate analysis showed that increased tumor size, high tumor grade, lymph node metastases, a positive superior mesenteric artery and retroperitoneal margin, and a positive resection margin on frozen section were significantly correlated with reduced OS (p<0.05). Twenty-two patients with positive resection margins on frozen section histology underwent further resection; R0 was achieved in 14 patients, with no significant difference in OS. CONCLUSIONS For patients who underwent pancreaticoduodenectomy for pancreatic carcinoma with positive resection margins on frozen section, further surgical resection to achieve R0 had no significant positive impact on OS.

Frozen section analysis of the pancreatic margin during pancreaticoduodenectomy for cancer: Does extending the resection to obtain a secondary R0 provide a survival benefit? Results of a systematic review

BACKGROUND

During pancreaticoduodenectomy, frozen section pancreatic margin analysis permits to extend the resection in case of a positive margin, to achieve R0 margin. We aim to assess if patients having an R0 margin following the extension of the pancreatectomy after a positive frozen section (secondary R0) have different survival compared to those with R1 resection or primary R0 resection.

METHODS

A systematic search was performed to identify all studies published up to March 2016 analyzing the survival of patients undergoing pancreaticoduodenectomy according to the results of frozen section pancreatic margin examination. Clinical effectiveness was synthetized through a narrative review with full tabulation of results.

RESULTS

Four studies published between 2010 and 2014 were retrieved, including 2580 patients. A primary R0 resection was obtained in a percentage of patients ranging from 36.2% to 85.5%, whereas secondary R0 in 9.4%-57.8% of cases and R1 in 5.1%-9.2%. Median survival ranged from 19 to 29 months in R0 patients, from 11.9 to 18 months in secondary R0, and from 12 to 23 months in R1 patients. None of the study demonstrated a survival benefit of extending the resection to obtain a secondary R0 pancreatic margin.

CONCLUSIONS

All the studies were concordant, and failed to demonstrate the survival benefit of additional pancreatic resection to obtain a secondary R0. However, inadequate surgery should not be advocated. This review suggests that re-resection of the pancreatic margin may have limited impact on patients' survival.

Factors predicting adequate lymph node yield in patients undergoing pancreatoduodenectomy for malignancy

Background

Most pancreatoduodenectomy resections do not meet the minimum of 12 lymph nodes recommended by the American Joint Committee on Cancer for accurate staging of periampullary malignancies. The purpose of this study was to investigate factors affecting the likelihood of adequate nodal yield in pancreatoduodenectomy specimens subject to routine pathological assessment.

Methods

Six hundred sixty-two patients subject to pancreatoduodenectomy between 1990 and 2013 for pancreatic, ampullary, and common bile duct cancers were reviewed. Predictors of yielding at least 12 lymph nodes were evaluated with a logistic regression model, and a survival analysis was carried out to verify the prognostic implications of nodal counts.

Results

The median number of evaluated nodes was 17 (interquartile range 11 to 25), and less than 12 lymph nodes were reported in surgical specimens of 179 (27 %) patients. Tumor diameter ≥20 mm (odds ratio [OR] 2.547, 95 % confidence interval [CI] 1.225 to 5.329, P = 0.013), lymph node metastases (OR 2.642, 95 % CI 1.378 to 5.061, P = 0.004), and radical lymphadenectomy (OR 5.566, 95 % CI 2.041 to 15.148, P = 0.01) were significant predictors of retrieving 12 or more lymph nodes. Lymph node counts did not influence the overall prognosis of the patients. However, a subgroup analysis carried out for individual cancer sites demonstrated that removing at least 12 lymph nodes is associated with better prognosis for pancreatic cancer.

Conclusions

Few variables affect adequate nodal yield in pancreatoduodenectomy specimens subject to routine pathological assessment. Considering the ambiguities related to the only modifiable factor identified, appropriate pathology training should be considered to increase nodal yield rather than more aggressive lymphatic dissection.

Redefining the R1 resection in patients with pancreatic ductal adenocarcinoma

Most cases of pancreatic ductal adenocarcinoma (PDAC) are lethal. Margin-negative surgical resection is a mainstay of treatment and the only chance of a cure. Differences in pathological reporting, surgical technique, definitions of resection margin, and group stratification all affect outcome analyses. Furthermore, there are controversial issues influencing the clinical interpretation of resection margin after pancreatectomy. There is no standardized definition of margin involvement in resected specimens of PDAC. The non-standardized pathologic approach explains the wide range of positive resection margin rates (13-71%) that have previously been reported. A standardized pathologic evaluation needs to be developed for proper assessment of resection margin after oncologic pancreatectomy. This manuscript reviews the current controversial issues in assessing resection margin in order to enhance understanding of the current status and potential role of pathological evaluation in patients with PDAC.

Comparison of Uncinate Process Cancer and Non-Uncinate Process Pancreatic Head Cancer

The special anatomical position accounts for unusual clinicopathological features of uncinate process cancer. This study aimed to compare clinicopathological features of patients with uncinate process cancer to patients with non-uncinate process pancreatic head cancer. Total 160 patients with pancreatic head cancer were enrolled and classified into two groups: uncinate process cancer and non-uncinate process pancreatic head cancer. We found that the ratio of vascular invasion was significantly higher in patients with uncinate process cancer than in patients with non-uncinate process pancreatic head cancer. In addition, the rate of R1 resection was significantly higher in patients with uncinate process cancer. Furthermore, the median disease-free survival (11 months vs. 15 months, p=0.043) and overall survival (15 months vs. 19 months, p=0.036) after R0 resection were lower for uncinate process cancer. Locoregional recurrence was more frequent (p=0.017) and earlier (12 months vs. 36 months; p=0.002) in patients with uncinate process cancer than in patients with non-uncinate process pancreatic head cancer. In conclusion, uncinate process cancer is more likely to invade blood vessel and has worse prognosis due to the earlier and more frequent locoregional recurrence.

Microscopic Residual Tumor After Pancreaticoduodenectomy: Is Standardization of Pathological Examination Worthwhile?

OBJECTIVES

R1 resection rate after pancreaticoduodenectomy (PD) for cancer is highly variable. The aim of this study was to verify if a standardized histopathological work-up of the specimen affects the rate of R1 resection after PD for cancer.

METHODS

Two groups of specimens were managed with (standardized method [SM] group) or without (non-standardized method [NSM] group) a SM of histopathological work-up. Each group included 50 cases of PD for periampullary cancer. Differences in terms of R1 resection rate between the 2 groups were evaluated. Correlation between R1 status and local recurrence was also evaluated.

RESULTS

The cohort of 100 patients consisted of 66 pancreatic ductal adenocarcinoma, 15 cholangiocarcinoma, and 19 ampullary cancer. The R1 resection rate resulted statistically higher in the SM group (66% vs 10%). Local recurrence was more frequently related to R1 resection in the SM group (34.3% of cases) than in NSM group (20% of cases).

CONCLUSIONS

The use of the SM of pathological evaluation of the specimen after PD for cancer determines a significant increase of R1 resection. This remarkable difference seems to be due to the different definition of minimum clearance. The SM seems to better discriminate patients in terms of risk of local recurrence.

Value of intraoperative neck margin analysis during Whipple for pancreatic adenocarcinoma: a multicenter analysis of 1399 patients

INTRODUCTION

During pancreaticoduodenectomy (PD) for ductal adenocarcinoma, a frozen section (FS) neck margin is typically assessed, and if positive, additional pancreas is removed to achieve an R0 margin. We analyzed the association of this practice with improved overall survival (OS).

METHODS

Patients who underwent PD for pancreatic ductal adenocarcinoma from January 2000 to August 2012 at 8 academic centers were classified by neck margin status as negative (R0) or microscopically positive (R1) on the basis of FS and permanent section (PS). Impact on OS of converting an FS-R1-neck margin to a PS-R0-neck margin by additional resection was assessed.

RESULTS

A total of 1399 patients had FS neck margins analyzed. Median OS was 19.7 months. On FS, 152 patients (10.9%) were R1, and an additional 51 patients (3.6%) had false-negative FS-R0 margins. PS-R0-neck was achieved in 1196 patients (85.5%), 131 patients (9.3%) remained PS-R1, and 72 patients (5.1%) were converted from FS-R1-to-PS-R0 by additional resection. Median OS for PS-R0-neck patients was 21.1 months versus 13.7 months for PS-R1-neck patients (P < 0.001) and 11.9 months for FS-R1-to-PS-R0 patients (P < 0.001). Both FS-R1-to-PS-R0 and PS-R1-neck patients had larger tumors (P = 0.001), more perineural invasion (P = 0.02), and more node positivity (P = 0.08) than PS-R0-neck patients. On multivariate analysis controlling for adverse pathologic factors, FS-R1-to-PS-R0 conversion remained associated with significantly worse OS compared with PS-R0-neck patients (hazard ratio: 1.55; P = 0.009).

CONCLUSIONS

For patients who undergo pancreaticoduodenectomy for pancreatic ductal adenocarcinoma, additional resection to achieve a negative neck margin after positive frozen section is not associated with improved OS.

Prognostic value of the lymph node ratio after resection of periampullary carcinomas

BACKGROUND

Data have indicated that the lymph node ratio (LNR) may be a better prognostic indicator than lymph node status in pancreatic cancer.

OBJECTIVES

To analyse the value of the LNR in patients undergoing resection for periampullary carcinomas.

METHODS

A cut off value of 0.2 was assigned to the LNR in accordance with published studies. The impact of histopathological factors including a LNR was analysed using Kaplan-Meier and Cox regression methods.

RESULTS

In total, 551 patients undergoing a resection (January 2000 to December 2010) were analysed. The median lymph node yield was 15, and 198 (34%) patients had a LNR > 0.2. In patients with a LNR of > 0.2, the median overall survival (OS) was 18 versus 33 months in patients with an LNR < 0.2 (P < 0.001). Univariate analysis demonstrated a LNR > 0.2, T and N stage, vascular or perineural invasion, grade and resection margin status to be significantly associated with OS. On multivariate analysis, only a LNR > 0.2, vascular or perineural invasion and margin positivity remained significant. In N1 disease, a LNR was able to distinguish survival in patients with a similar lymph node burden, and correlated with more aggressive tumour pathological variables.

CONCLUSION

A LNR > 0.2, and not lymph note status, is an independent prognostic factor for OS indicating the LNR should be utilized in outcome stratification.

Pancreaticoduodenectomy for pancreatic ductal adenocarcinoma: a French multicentre prospective evaluation of resection margins in 150 evaluable specimens

OBJECTIVES

This study aimed to determine the impact of a standardized pathological protocol on resection margin status after pancreaticoduodenectomy (PD) for ductal adenocarcinoma.

METHODS

A total of 150 patients operated during 2008-2010 were included in a prospective multicentre study using a 'quality protocol'. Multicolour inking by the surgeon identified three resection margins: the portal vein-superior mesenteric vein margin (PV-SMVm) or mesenterico-portal vein groove; the superior mesenteric artery margin (SMAm), and the posterior margin. Resection margins were stratified by 0.5-mm increments (range: 0-2.0 mm). Pancreatic neck, bile duct and intestinal margins were also analysed. Correlations between histopathological factors and survival in the 0-mm resection margin group were analysed.

RESULTS

Thirty-six patients (24%) had a PV-SMV resection (PV-SMVR). An analysis of resections categorized according to margin distances of 0 mm, <1.0 mm, <1.5 mm and <2.0 mm confirmed R1 resections in 35 (23%), 91 (61%), 94 (63%) and 107 (71%) patients, respectively. The most frequently invaded resection margin was the PV-SMVm (35% of all patients) and PV-SMVR was the only factor correlated with a higher risk for at least one 0-mm positive resection margin on multivariate analysis (P < 0.001). Two-year progression-free survival (PFS) and median PFS time in patients with R0 and R1 resections (at 0 mm), respectively, were 42.0% and 26.5%, and 19.5 months and 10.5 months, respectively (P = 0.02). A positive PV-SMVm and SMAm had significant impact on PFS, whereas a positive posterior margin had no impact.

CONCLUSIONS

Pancreaticoduodenectomy requiring PV-SMVR was associated with a higher risk for R1 resection. The standardization of histopathological analysis has a clinically relevant impact on PFS data.

Precursor lesions of early onset pancreatic cancer

Early onset pancreatic cancer (EOPC) constitutes less than 5% of all newly diagnosed cases of pancreatic cancer (PC). Although histopathological characteristics of EOPC have been described, no detailed reports on precursor lesions of EOPC are available. In the present study, we aimed to describe histopathological picture of extratumoral parenchyma in 23 cases of EOPCs (definition based on the threshold value of 45 years of age) with particular emphasis on two types of precursor lesions of PC: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMNs). The types, grades, and densities of precursor lesions of PC were compared in patients with EOPCs, in young patients with neuroendocrine neoplasms (NENs), and in older (at the age of 46 or more) patients with PC. PanINs were found in 95.6% of cases of EOPCs. PanINs-3 were found in 39.1% of EOPC cases. Densities of all PanIN grades in EOPC cases were larger than in young patients with NENs. Density of PanINs-1A in EOPC cases was larger than in older patients with PC, but densities of PanINs of other grades were comparable. IPMN was found only in a single patient with EOPC but in 20% of older patients with PC. PanINs are the most prevalent precursor lesions of EOPC. IPMNs are rarely precursor lesions of EOPC. Relatively high density of low-grade PanINs-1 in extratumoral parenchyma of patients with EOPC may result from unknown multifocal genetic alterations in pancreatic tissue in patients with EOPCs.

Definition of microscopic tumor clearance (r0) in pancreatic cancer resections

To date, curative resection is the only chance for cure for patients suffering from pancreatic ductal adenoacarcinoma (PDAC). Despite low reported rates of microscopic tumor infiltration (R1) in most studies, tumor recurrence is a common finding in patients with PDAC and contributes to extremely low long-term survival rates. Lack of international definition of resection margins and of standardized protocols for pathological examination lead to high variation in reported R1 rates. Here we review recent studies supporting the hypothesis that R1 rates are highly underestimated in certain studies and that a microscopic tumor clearance of at least 1 mm is required to confirm radicality and to serve as a reliable prognostic and predictive factor.