Faculty Bibliography

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.

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.

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.

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 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.

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.

BACKGROUND:While previously believed to be mutually exclusive, concomitant mutation of Kirsten rat sarcoma viral oncogene homolog (KRAS)- and V-raf murine sarcoma b-viral oncogene homolog B1 (BRAF)-mutated colorectal carcinoma (CRC), has been described in rare instances and been associated with advanced-stage disease. The present case series is the first to report on the implications of concurrent KRAS/BRAF mutations among surgically treated patients, and the largest set of patients with surgically treated colorectal liver metastasis (CRLM) and data on KRAS/BRAF mutational status thus far described. CASE SERIES:We present cases from an international, multi-institutional cohort of patients that underwent hepatic resection for CRLM between 2000-2015 at seven tertiary centers. The incidence of KRAS/BRAF mutation in patients with CRLM was 0.5% (4/820). Of these cases, patient 1 (T2N1 primary, G13D/V600E), patient 2 (T3N1 primary, G12V/V600E) and patient 3 (T4N2 primary, G13D/D594N) succumbed to their disease within 485, 236 and 79 days respectively, post-hepatic resection. Patient 4 (T4 primary, G12S/G469S) was alive 416 days after hepatic resection. CONCLUSION:The present case series suggests that the incidence of concomitant KRAS/BRAF mutations in surgical cohorts may be higher than previously hypothesized, and associated with more variable survival outcomes than expected.

BACKGROUND:The impact of neoadjuvant stereotactic body radiation therapy on postoperative complications for patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma remains unclear. Limited studies have compared neoadjuvant stereotactic body radiation therapy versus conventional chemoradiation therapy. A retrospective study was performed to determine if perioperative complications were different among patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma receiving neoadjuvant stereotactic body radiation therapy or chemoradiation therapy. METHODS:Patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma who underwent neoadjuvant chemotherapy with stereotactic body radiation therapy or chemoradiation therapy followed by pancreatectomy at the Johns Hopkins Hospital between 2008 and 2015 were included. Predictive factors for severe complications (Clavien grade ≥ III) were assessed by univariate and multivariate analyses. RESULTS:A total of 168 patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma underwent neoadjuvant chemotherapy and RT followed by pancreatectomy. Sixty-one (36%) patients underwent stereotactic body radiation therapy and 107 (64%) patients received chemoradiation therapy. Compared with the chemoradiation therapy cohort, the neoadjuvant stereotactic body radiation therapy cohort was more likely to have locally advanced pancreatic ductal adenocarcinoma (62% vs 43% P = .017) and require a vascular resection (54% vs 37%, P = .027). Multiagent chemotherapy was used more commonly in the stereotactic body radiation therapy cohort (97% vs 75%, P < .001). Postoperative complications (Clavien grade ≥ III 23% vs 28%, P = .471) were similar between stereotactic body radiation therapy and chemoradiation therapy cohort. No significant difference in postoperative bleeding or infection was noted in either group. CONCLUSION:Compared with chemoradiation therapy, neoadjuvant stereotactic body radiation therapy appears to offer equivalent rates of perioperative complications in patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma despite a greater percentage of locally advanced disease and more complex operative treatment.

PURPOSE:Introduction of effective neoadjuvant therapy for pancreas cancer has resulted in complex and aggressive operations involving vasculature resection. This results in complicated postoperative CT appearance of vasculature, which in addition to high rate of recurrence makes interpretation of imaging difficult. The aim of this study was to identify patterns of postoperative appearance of portal vein-superior mesenteric vein complex (PV-SMV). METHODS:A retrospective study was conducted on patients undergoing pancreaticoduodenectomy with PV-SMV resection and reconstruction (PVR) between 2004 and 2014. Clinicopathological data were collected from a prospectively maintained database. Postoperative CT scans were reviewed to identify patterns of venous and perivenous features. RESULTS:The mean age, of 70 patients included in the study, was 63.0 ± 12.2 years and 37 (52.9%) were males. The median time between surgery and postoperative scan was 10 days (IQR 7-25). Tangential resection with PVR via primary closure or use of a patch was performed in 37 (52.9%) patients while the rest underwent segmental resection with PVR via end-to-end anastomosis or use of a graft. Postoperative patterns of PV-SMV included concentric narrowing (N = 40, 57.1%), eccentric narrowing (N = 19, 27.1%) or partial venous thrombosis (N = 7, 10.0%). Perivenous features included perivenous fluid collection and induration (N = 57, 81.4%) and mass-like soft tissue thickening (N = 13, 18.6%). Long-term follow-up was available on 44 (62.9%) patients of which 28 (63.6%) demonstrated no recurrence of disease. CONCLUSION:This is a novel study that identifies and categorizes postoperative features of PV-SMV after PVR. These features overlap with those of disease recurrence and their better understanding can results in an accurate interpretation of postoperative imaging.