Intraoperative assessment of the Whipple resection specimen

Frozen sections in gastrointestinal, pancreatobiliary and hepatic pathology: A review

In the digestive system, intraoperative frozen sections are commonly requested to assess surgical margins, obtain diagnostic material, and evaluate incidental lesions. Frozen section results may alter surgical planning or lead to the discontinuation of the procedure. As a practicing pathologist, understanding the indication for frozen section and its impact on patient management would improve communication with surgeons. Likewise, understanding what to look for and focus on, what to relay to the requester and common diagnostic pitfalls would improve the quality of service one provides and patients' outcome. Herein we provide an overview of common frozen sections encountered during variable abdominal procedures to include pancreaticoduodenectomy, gastrectomy, appendectomy, colorectal resection and Hirschsprung pull-through along with ample microscopic images.

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.

Validation of Remote Digital Frozen Sections for Cancer and Transplant Intraoperative Services

INTRODUCTION

Whole-slide imaging (WSI) technology can be used for primary diagnosis and consultation, including intraoperative (IO) frozen section (FS). We aimed to implement and validate a digital system for the FS evaluation of cancer and transplant specimens following recommendations of the College of American Pathologists.

MATERIALS AND METHODS

FS cases were routinely scanned at ×20 employing the "Navigo" scanner system. IO diagnoses using glass versus digital slides after a 3-week washout period were recorded. Intraobserver concordance was evaluated using accuracy rate and kappa statistics. Feasibility of WSI diagnoses was assessed by the way of sensitivity, specificity, as well as positive and negative predictive values. Participants also completed a survey denoting scan time, time spent viewing cases, preference for glass versus WSI, image quality, interface experience, and any problems encountered.

RESULTS

Of the 125 cases submitted, 121 (436 slides) were successfully scanned including 93 oncological and 28 donor-organ FS biopsies. Four cases were excluded because of failed digitalization due to scanning problems or sample preparation artifacts. Full agreement between glass and digital-slide diagnosis was obtained in 90 of 93 (97%, κ = 0.96) oncology and in 24 of 28 (86%, κ = 0.91) transplant cases. There were two major and one minor discrepancy for cancer cases (sensitivity 100%, specificity 96%) and two major and two minor disagreements for transplant cases (sensitivity 96%, specificity 75%). Average scan and viewing/reporting time were 12 and 3 min for cancer cases, compared to 18 and 5 min for transplant cases. A high diagnostic comfort level among pathologists emerged from the survey.

CONCLUSIONS

These data demonstrate that the "Navigo" digital WSI system can reliably support an IO FS service involving complicated cancer and transplant cases.

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.

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.

Resection margin clearance in pancreatic cancer after implementation of the Leeds Pathology Protocol (LEEPP): clinically relevant or just academic?

BACKGROUND AND OBJECTIVES

The aim of this study was to assess the overall survival (OS) after R0/R1 resections in patients with pancreatic ductal adenocarcinoma (PDAC) of the pancreatic head after implementation of a standardized histopathologic protocol (Leeds Pathology Protocol, LEEPP).

METHODS

One hundred and twenty-five patients underwent surgical resection because of PDAC of the pancreatic head. Patients were histopathologically examined according to a standardized protocol. Their oncologic outcome and clinicopathologic data were compared with those of a patient group before implementation of the LEEPP (n = 116).

RESULTS

The R1 rate increased significantly from 13 to 52 %. There was no significant difference in OS between R0 and R1 resections. The median OS in patients with a tumor clearance of less than 2 mm from the resection margin was 15.1 months (12.1-18.1 months) versus 22.2 months (7.8-36.7 months) (P = 0.046). Multivariate analysis revealed a margin clearance or 2 mm and more as an independent prognosticator for OS.

CONCLUSIONS

With applying the LEEPP, there was still no significant correlation between the R-status and OS in patients with PDAC. However, since a margin clearance of 2 mm or more is a predictive factor for OS, the R1 definition might have to be adapted in PDAC.

Tumor infiltration in the medial resection margin predicts survival after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma

BACKGROUND

Microscopic tumor involvement (R1) in different surgical resection margins after pancreaticoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC) has been debated.

METHODS

Clinico-pathological data for 258 patients who underwent PD between 2001 and 2010 were retrieved from a prospective database. The rates of R1 resection in the circumferential resection margin (pancreatic transection, medial, posterior, and anterior surfaces) and their prognostic influence on survival were assessed.

RESULTS

For PDAC, the R1 rate was 57.1% (48/84) for any margin, 31.0% (26/84) for anterior surface, 42.9% (36/84) for posterior surface, 29.8% (25/84) for medial margin, and 7.1% (3/84) for pancreatic transection margin. Overall and disease-free survival for R1 resections were significantly worse than those for R0 resection (17.2 vs. 28.7 months, P = 0.007 and 12.3 vs. 21.0 months, P = 0.019, respectively). For individual margins, only medial positivity had a significant impact on survival (13.8 vs. 28.0 months, P < 0.001), as opposed to involvement in the anterior (19.7 vs. 23.3 months, P = 0.187) or posterior margin (17.5 vs. 24.2 months, P = 0.104). Multivariate analysis demonstrated R0 medial margin was an independent prognostic factor (P = 0.002, HR = 0.381; 95% CI 0.207-0.701).

CONCLUSION

The medial surgical resection margin is the most important after PD for PDAC, and an R1 resection here predicts poor survival.

Tumour growth is more dispersed in pancreatic head cancers than in rectal cancer: implications for resection margin assessment

AIMS

The UK definition of microscopic resection margin involvement (R1) in pancreatic head cancer, based on tumour lying <1 mm from the margin, has been adopted from rectal cancer, but has never been validated. The aim of this study was to assess the adequacy of the R1 definition for pancreatic head cancers by comparing the growth patterns of rectal (RC), pancreatic (PC), ampullary (AC) and distal bile duct (DBC) adenocarcinomas.

METHODS AND RESULTS

Distances between tumour cells and tumour cell density in the tumour centre and periphery were quantified by Minimum Spanning Tree (MST) analysis in 10 cases of the four cancer groups. In RC, the MST distance was similar throughout the entire width of the tumour, whereas in PC, DBC and AC it was significantly larger at the periphery than at the tumour centre (P ≤ 0.003). While results were similar for PC and DBC, however, distances at the centre and periphery of both cancers were larger compared to AC (P ≤ 0.046). Tumour cell density dropped at the periphery of PC to 31% of that at the centre, compared to 83% in RC (P < 0.0002).

CONCLUSIONS

Tumour growth in pancreatic head cancers is more dispersed than in RC, particularly in the tumour periphery. Revision of the R1 definition for pancreatic head cancer may therefore need to be considered.

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.

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

Surgical margin status of the pancreaticoduodenectomy specimen is an independent predictor of survival in patients with pancreatic head cancer. Although most surgical pathologists are familiar with the protocols for grossing and evaluation of the various margins of the specimen, the currently prevailing definitions of the retroperitoneal surgical margin minimize the fact that this margin is actually a combination of surfaces of different anatomical structures. The unfamiliarity with its detailed anatomy often creates communication gaps when the pathologic findings are presented to other members of the multidisciplinary team. The following discussion is the collective opinion of hepato-pancreato-biliary pathologists in two tertiary care Canadian medical centers in this field. It describes the authors' proposed nomenclature and landmarks for anatomic mapping of the retroperitoneal margin of the pancreaticoduodenectomy resected specimen. Increasing familiarity with the subtleties of the retroperitoneal margin is expected to improve communication and sets the stage for future quality improvement initiatives and translational research in the multidisciplinary setting.

Resection margins and R1 rates in pancreatic cancer--are we there yet?

The prognosis of pancreatic cancer is poor, even for those patients who undergo surgical resection. The rate of local recurrence is high, despite the fact that in most series complete ('R0') resection is reported to be achieved in the majority of patients. The discrepancy between pathological assessment and clinical outcome indicates that microscopic margin involvement (R1) is frequently underreported, and potential causes for this are discussed in this review. Special emphasis is given to the variation that exists between currently used dissection techniques and their impact on the assessment of the resection margins in pancreatoduodenectomy specimens.

Improved lymph node retrieval in Whipple specimens as a result of implementation of a new uncinate margin protocol

BACKGROUND

Lymph node status is an important prognostic factor in pancreatic and peri-ampullary adenocarcinoma. We recently changed our protocol for assessment of the uncinate margin of Whipple specimens and noted that lymph nodes were often present in uncinate margin sections.

MATERIALS AND METHODS

Whipple specimens from 2004 to 2006 were divided into two groups, those that were handled according to the en face protocol, and those handled according to the radial protocol. The numbers of lymph nodes found in uncinate margin sections were assessed, as well as the total number of nodes found in the specimen.

RESULTS

Sixteen cases were handled according to the en face protocol, and 20 according to the radial protocol. In the en face group, 2 benign nodes were found in the uncinate margin (0.1 nodes per case), while in the radial group, 36 nodes (1.8 nodes per case) were identified (p=0.0005). Eight cases in the latter group had positive nodes in the uncinate margin sections. In two of these cases the positive lymph node was the only lymph node with metastasis, and in an additional case the involved node was one of two positive lymph nodes. Total lymph node retrieval was 15.5 lymph nodes per case in the en face group, and 20 nodes per case in the radial group (p=0.02).

DISCUSSION

The improved lymph node retrieval may be due to additional nodes found in radial sections of the uncinate margin, or alternatively, due to increased vigilance in specimen handling. In 3 of 20 cases, nodes found in the radial sections influenced staging.