Faculty Bibliography

BACKGROUND:Varying definitions of resection margin clearance are currently employed among patients with colorectal cancer liver metastases (CRLM). Specifically, a microscopically positive margin (R1) has alternatively been equated with an involved margin (margin width = 0 mm) or a margin width < 1 mm. Consequently, patients with a margin width of 0-1 mm (sub-mm) are inconsistently classified in either the R0 or R1 categories, thus obscuring the prognostic implications of sub-mm margins. METHODS:Six hundred thirty-three patients who underwent resection of CRLM were identified. Both R1 definitions were alternatively employed and multivariable analysis was used to determine the predictive power of each definition, as well as the prognostic implications of a sub-mm margin. RESULTS:Five hundred thirty-nine (85.2%) patients had a margin width ≥ 1 mm, 42 had a sub-mm margin width, and 52 had an involved margin (0 mm). A margin width ≥ 1 mm was associated with improved survival vs. a sub-mm margin (65 vs. 36 months; P = 0.03) or an involved margin (65 vs. 33 months; P < 0.001). No significant difference in survival was detected between patients with involved vs. sub-mm margins (P = 0.31). A sub-mm margin and an involved margin were both independent predictors of worse OS (HR 1.66, 1.04-2.67; P = 0.04, and HR 2.14, 1.46-3.16; P < 0.001, respectively) in multivariable analysis. Importantly, after combining the two definitions, patients with either an involved margin or a sub-mm margin were associated with worse OS in multivariable analysis (HR 1.94, 1.41-2.65; P < 0.001). CONCLUSIONS:Patients with involved or sub-mm margins demonstrated a similar inferior OS vs. patients with a margin width > 1 mm. Consequently, a uniform definition of R1 as a margin width < 1 mm should perhaps be employed by future studies.

Importance:BRAF mutations are reportedly associated with aggressive tumor biology. However, in contrast with primary colorectal cancer, the association of V600E and non-V600E BRAF mutations with survival and recurrence after resection of colorectal liver metastases (CRLM) has not been well studied. Objective:To investigate the prognostic association of BRAF mutations with survival and recurrence independently and compared with other prognostic determinants, such as KRAS mutations. Design, Setting, and Participants:In this cohort study, all patients who underwent resection for CRLM with curative intent from January 1, 2000, through December 31, 2016, at the institutions participating in the International Genetic Consortium for Colorectal Liver Metastasis and had data on BRAF and KRAS mutational status were retrospectively identified. Multivariate Cox proportional hazards regression models were used to assess long-term outcomes. Interventions:Hepatectomy in patients with CRLM. Main Outcomes and Measures:The association of V600E and non-V600E BRAF mutations with disease-free survival (DFS) and overall survival (OS). Results:Of 853 patients who met inclusion criteria (510 men [59.8%] and 343 women [40.2%]; mean [SD] age, 60.2 [12.4] years), 849 were included in the study analyses. Forty-three (5.1%) had a mutated (mut) BRAF/wild-type (wt) KRAS (V600E and non-V600E) genotype; 480 (56.5%), a wtBRAF/wtKRAS genotype; and 326 (38.4%), a wtBRAF/mutKRAS genotype. Compared with the wtBRAF/wtKRAS genotype group, patients with a mutBRAF/wtKRAS genotype more frequently were female (27 [62.8%] vs 169 [35.2%]) and 65 years or older (22 [51.2%] vs 176 [36.9%]), had right-sided primary tumors (27 [62.8%] vs 83 [17.4%]), and presented with a metachronous liver metastasis (28 [64.3%] vs 229 [46.8%]). On multivariable analysis, V600E but not non-V600E BRAF mutation was associated with worse OS (hazard ratio [HR], 2.76; 95% CI, 1.74-4.37; P < .001) and DFS (HR, 2.04; 95% CI, 1.30-3.20; P = .002). The V600E BRAF mutation had a stronger association with OS and DFS than the KRAS mutations (β for OS, 10.15 vs 2.94; β for DFS, 7.14 vs 2.27). Conclusions and Relevance:The presence of the V600E BRAF mutation was associated with worse prognosis and increased risk of recurrence. The V600E mutation was not only a stronger prognostic factor than KRAS but also was the strongest prognostic determinant in the overall cohort.

OBJECTIVES:To describe the survival outcome of patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma (BR/LA-PDAC) who have a pathologic complete response (pCR) following neoadjuvant chemoradiation. BACKGROUND:Patients with BR/LA-PDAC are often treated with neoadjuvant chemoradiation in an attempt to downstage the tumor. Uncommonly, a pCR may result. METHODS:A retrospective review of a prospectively maintained database was performed at a single institution. pCR was defined as no viable tumor identified in the pancreas or lymph nodes by pathology. A near complete response (nCR) was defined as a primary tumor less than 1 cm, without nodal metastasis. Overall survival (OS) and disease-free survival (DFS) were reported. RESULTS:One hundred eighty-six patients with BR/LA-PDAC underwent neoadjuvant chemoradiation and subsequent pancreatectomy. Nineteen patients (10%) had a pCR, 29 (16%) had an nCR, and the remaining 138 (74%) had a limited response. Median DFS was 26 months in patients with pCR, which was superior to nCR (12 months, P = 0.019) and limited response (12 months, P < 0.001). The median OS of nCR (27 months, P = 0.003) or limited response (26 months, P = 0.001) was less than that of pCR (more than 60 months). In multivariable analyses pCR was an independent prognostic factor for DFS (HR = 0.45; 0.22-0.93, P = 0.030) and OS (HR=0.41; 0.17-0.97, P = 0.044). Neoadjuvant FOLFIRINOX (HR=0.47; 0.26-0.87, P = 0.015) and negative lymph node status (HR=0.57; 0.36-0.90, P = 0.018) were also associated with improved survival. CONCLUSIONS:Patients with BR/LA-PDAC who had a pCR after neoadjuvant chemoradiation had a significantly prolonged survival compared with those who had nCR or a limited response.

BACKGROUND:Lymphoepithelial cysts (LECs) are rare pancreatic cystic lesions. Since LECs are benign, preoperative diagnosis is important to differentiate from a cystic neoplasm and avoid unnecessary surgery. The aim of this study was to identify clinical, radiographic and cytopathologic features associated with LECs. METHODS:A retrospective review was performed of patients diagnosed with LEC between 1995 and 2017 at our hospital. Clinicopathologic and radiographic imaging features were documented. RESULTS:Of 29 patients with pancreatic LEC, 22 underwent surgical resection. The majority were male (n = 24) with a median age of 55 years (range, 21-74). During the evaluation, all patients underwent a CT, with endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) biopsy (n = 22) and/or MRI/MRCP (n = 11) performed in a smaller number of patients. A combination of exophytic tumor growth on imaging and the presence of specific cytomorphologic features on the EUS-FNA cytology biopsy led to the correct diagnosis of LEC and prevention of unnecessary surgery in 7 patients. DISCUSSION:Differentiating LECs from premalignant pancreatic cystic neoplasms remains difficult. Findings of an exophytic growth pattern of the lesion on abdominal imaging and the presence of specific cytomorphologic features in the EUS-FNA biopsy could help clinicians diagnose LEC preoperatively.

Colorectal liver metastases (CRLM) present an important clinical challenge in both surgical and medical oncology. Despite improvements in management, survival among patients undergoing resection of CRLM is still very variable and there is a paucity of clinical trial data and reliable biomarkers that could guide prognostic forecasts, treatment selection, and follow-up. Fortunately, recent advances in molecular biology and tumor sequencing have identified a number of critical genetic loci and proliferation markers that may hold the key to understanding the biologic behavior of CRLM; specifically, mutations of KRAS, BRAF, TP53, PIK3CA, APC, expression of Ki-67, and the presence of microsatellite instability appear to have a decisive impact on prognosis and response to treatment in patients with CRLM. While the applicability of genetic biomarkers in everyday clinical practice remains conditional on the development of inexpensive bedside sequencing, targeted therapies, and the conduct of appropriate clinical trials, the promise of personalized treatment may be closer to realization than ever before.

Visualizing pathologies in three dimensions can provide unique insights into the biology of human diseases. A rapid and easy-to-implement dibenzyl ether-based technique was used to clear thick sections of surgically resected human pancreatic parenchyma. Protocols were applicable to both fresh and formalin-fixed, paraffin-embedded tissue. The penetration of antibodies into dense pancreatic parenchyma was optimized using both gradually increasing antibody concentrations and centrifugal flow. Immunolabeling with antibodies against cytokeratin 19 was visualized using both light sheet and confocal laser scanning microscopy. The technique was applied successfully to 26 sections of pancreas, providing three-dimensional (3D) images of normal pancreatic tissue, pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasms, and infiltrating pancreatic ductal adenocarcinomas. 3D visualization highlighted processes that are hard to conceptualize in two dimensions, such as invasive carcinoma growing into what appeared to be pre-existing pancreatic ducts and within venules, and the tracking of long cords of neoplastic cells parallel to blood vessels. Expanding this technique to formalin-fixed, paraffin-embedded tissue opens pathology archives to 3D visualization of unique biosamples and rare diseases. The application of immunolabeling and clearing to human pancreatic parenchyma provides detailed visualization of normal pancreatic anatomy, and can be used to characterize the 3D architecture of diseases including pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and pancreatic ductal adenocarcinomas.

BACKGROUND:The most appropriate nodal staging for pancreatic neuroendocrine neoplasms (PanNENs) is unclear. Aim of the study was to evaluate the effect of the number of positive lymph nodes on prognosis after pancreaticoduodenectomy for PanNENs. METHODS:A retrospective analysis of pancreaticoduodenectomies for nonfunctioning PanNENs was performed. PanNENs with nodal metastases (N+) were classified into N1 (1 to 3 positive lymph nodes) and N2 (4 or more positive lymph nodes). Univariate and multivariate analyses of disease-free survival were performed. RESULTS:157 patients were included. 99 patients (63%) had N0 PanNENs whereas 58 patients (37%) had nodal involvement (N+). Patients with N0 PanNENs had a 3-year disease-free survival rate of 89% compared with 83% and 75% in patients with N1 and N2 PanNENs, respectively (P < 0.0001). Independent predictors of disease-free survival were the presence of necrosis, lymph node ratio and nodal status. Factors positively correlated with the number of positive lymph nodes were the Ki67 value, the T stage and the number of examined lymph nodes. Similar percentage of N0 and N+ PanNENs was demonstrated for a cut-off of 13 examined lymph nodes. CONCLUSIONS:The number of positive lymph nodes is accurate in predicting recurrence for PanNENs. Thirteen examined lymph nodes seems to be the minimum number of lymph nodes to be resected/examined in patients who undergo pancreaticoduodenectomy for PanNENs.

OBJECTIVE:To examine the impact of surgical margin width on survival following R0 hepatic resection for colorectal metastases (CRLM). SUMMARY OF BACKGROUND DATA:Although negative resection margin is considered of paramount importance for the prognosis of patients with colorectal liver metastases, optimal resection margin width remains controversial. METHODS:Eligible studies examining the association between margin status after R0 hepatic resection for CRLM and survival, including overall survival (OS) and disease-free survival (DFS) were sought using the Medline, Cochrane, and EMBASE databases. Random-effects models were used for the calculation of pooled relative risks (RRs) with their 95% confidence intervals (95% CIs). RESULTS:Thirty-four studies were deemed eligible for inclusion representing a cohort of 11,147 hepatic resections. Wider resection margin (>1 vs <1 cm) was significantly associated with improved OS at 3 years (pooled RR = 0.86, 95% CI: 0.79-0.95), 5 years (pooled RR = 0.91, 95% CI: 0.85-0.97), and 10 years (pooled RR = 0.94, 95% CI: 0.88-1.00). Similarly, DFS was positively associated with >1 cm resection margin at 3, 5, and 10 years. Interestingly, >1 mm (vs <1 mm) resection margin was significantly associated with improved OS at all-time points. Meta-regression analyses did not reveal any significant modifying role of the study features under investigation, such as the administration of neoadjuvant/adjuvant therapy. CONCLUSIONS:Importantly, our findings suggest that while a >1 mm margin is associated with better prognosis than a submillimeter margin, achieving a margin >1 cm may result in even better oncologic outcomes and should be considered if possible.

BACKGROUND:The risk of invasive cancer in resected intraductal papillary mucinous neoplasm with main pancreatic duct involvement is 33%-60%. Most guidelines, therefore, advise resection of main duct intraductal papillary mucinous neoplasm and mixed type intraductal papillary mucinous neoplasm in surgically fit patients, although advice on the surgical strategy (partial or total pancreatectomy) differs. We performed a survey amongst international experts to guide the design of future studies and help to prepare for a single international set of guidelines. METHODS:An online survey including case vignettes was sent to 221 international experts who had published on main duct/mixed type intraductal papillary mucinous neoplasm in the previous decade and to all surgeon and gastroenterologist members of the pancreatic cyst guideline committees of the European Study Group and the International Association of Pancreatology. RESULTS:Overall, 97 experts (67 surgeons, 30 gastroenterologists) from 19 countries replied (44% response rate). Most (93%) worked in an academic hospital, with a median of 15 years' experience with intraductal papillary mucinous neoplasm treatment. In main duct/mixed type intraductal papillary mucinous neoplasm patients with pancreatic duct dilation (>5 mm) in the entire pancreas, 41% (n = 37) advised nonoperative surveillance every 3-6 months, whereas 59% (n = 54) advised operative intervention. Of those who advised operative intervention, 46% (n = 25) would perform a total pancreatectomy and 31% (n = 17) pancreatoduodenectomy with follow-up. No structural differences in advice were seen between surgeons and gastroenterologists, between continents where the respondents lived, and based on years of experience. CONCLUSION/CONCLUSIONS:This international survey identified a clinically relevant lack of consensus in the treatment strategy in main duct/mixed type intraductal papillary mucinous neoplasm among experts. Studies with long-term follow-up including quality of life after partial and total pancreatectomy for main duct/mixed type intraductal papillary mucinous neoplasm are required.

OBJECTIVE:To describe accurately the pattern, timing, and predictors of disease recurrence after a potentially curative resection for pancreatic ductal adenocarcinoma (PDAC). SUMMARY BACKGROUND DATA:After surgery for PDAC, most patients will develop disease recurrence. Understanding the patterns and timing of disease failure can help guide improvements in therapy. METHODS:Patients who underwent pancreatectomy for PDAC at the Johns Hopkins Hospital between 2000 and 2010 were included. Exclusion criteria were incomplete follow-up records, follow-up <24 months, and neoadjuvant therapy. The first recurrence site was recorded and recurrence-free survival (RFS) was estimated using Kaplan-Meier curves. Predictive factors for specific recurrence patterns were assessed by univariate and multivariate analyses using Cox-proportional hazard regression models. RESULTS:From the identified cohort of 1103 patients, 692 patients had comprehensive and detailed follow-up data available. At a median follow-up of 25.3 months, 531 (76.7%) of the 692 had recurred after a median RFS of 11.7 months. Most patients recurred at isolated distant sites (n = 307, 57.8%), while isolated local recurrence was seen in 126 patients (23.7%). Liver-only recurrence (n = 134, 25.2%) tended to occur early (median 6.9 mo), while lung-only recurrence (n = 78, 14.7%) occurred later (median 18.6 mo). A positive lymph node ratio >0.2 was a strong predictor for all distant disease recurrence. Patients receiving adjuvant chemotherapy or chemoradiotherapy had fewer recurrences and a longer RFS of 18.0 and 17.2 months, respectively. CONCLUSIONS:Specific recurrence locations have different predictive factors and possess distinct RFS curves, supporting the hypothesis that unique biological differences exist among tumors leading to distinct patterns of recurrence.