Faculty Bibliography

BACKGROUND:A major response to pre-hepatectomy chemotherapy has been associated with improved survival in patients who undergo resection of colorectal liver metastases (CRLM). However, the role of tumor biology, as exemplified by overall and codon-specific KRAS mutational status, in predicting response to chemotherapy is not well defined. METHODS:Pathologic response was characterized as minor or major depending on the percentage of remnant viable cells (>50% vs <50%, respectively). Multivariable logistic regression was used to identify factors associated with major response. RESULTS:319 patients met inclusion criteria. 229 patients had a KRAS wild-type (wtKRAS) tumor and 90 harbored KRAS mutations (mutKRAS). A major pathologic response was more commonly noted in patients with wtKRAS compared to mutKRAS (48.5% vs 33.3%, P = 0.01) and wtKRAS status remained independently associated with a major response (P = 0.04). On a codon-specific level, major pathologic response occurred less frequently in those with codon 13 mutations (17.7%) compared to those with codon 12 (35.4%), and other KRAS mutations (33.3%). Importantly, codon 13 mutations were independently associated with minor pathologic response (P = 0.023). CONCLUSIONS:Patients with wtKRAS tumors appear to have the highest likelihood of experiencing a major response after preoperative chemotherapy. Future studies in "all-comer" cohorts are needed to confirm these findings and further investigate the response of codon 13 mutations.

Pancreatic cystic neoplasms (PCN) are a heterogeneous group of pancreatic cysts that include intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, serous cystic neoplasms and other rare cystic lesions, all with different biological behaviours and variable risk of progression to malignancy. As more pancreatic cysts are incidentally discovered on routine cross-sectional imaging, optimal surveillance for patients with PCN is becoming an increasingly common clinical problem, highlighting the need to balance cancer prevention with the risk of (surgical) overtreatment. This Review summarizes the latest developments in the diagnosis and management of PCN, including the quality of available evidence. Also discussed are the most important differences between the PCN guidelines from the American Gastroenterological Association, the International Association of Pancreatology and the European Study Group on Cystic Tumours of the Pancreas, including diagnostic and follow-up strategies and indications for surgery. Finally, new developments in the management of patients with PCN are addressed.

Background: Intraductal papillary mucinous neoplasm (IPMN) is premalig-nant pancreatic lesion. International guidelines suggest several treatments and malignancy predictors but offer limited predictors of individual risk. A nomo-gram to predict individual IPMN malignancy risk was released with good diagnostic performance, basedona cohort of2258 Korean or Japanese patients with IPMN. This study validated a nomogram to predict malignancy risk and inva-siveness of IPMN, using Eastern and Western cohorts.
Method(s): We collected clinicopathological and radiological data of patients who underwent pancreas resection for IPMN at 4 centers each in Eastern and Western countries. After excluding patients with >=1 missing malignancy predictor in the nomogram (main pancreatic duct diameter, cyst size, presence of mural nodule, serum CEA and CA 19-9 levels, and age), we analyzed data of the remaining 393 patients (Eastern: n = 265; Western: n = 128).
Result(s): Although mean age, sex, log value of serum CA 19-9, tumor location, main duct diameter, cyst size and presence of mural nodule differed between the Korea/Japan, Eastern and Western cohorts, rates of malignancy and invasive cancer did not significantly differ. Areas under the receiver operating characteristics curve (AUC) values using the nomogram to predict malignancy were Eastern: 0.745, Western: 0.856, and combined cohorts: 0.776; and to predict in-vasiveness were Eastern: 0.736, Western: 0.891, and combined cohorts: 0.788.
Conclusion(s): External validation of the nomogram showed good performance in predicting malignancy and invasive cancer in both Eastern and Western IPMN patients. The nomogram could be globally applicable to decide customized treatment options for patients with IPMN

BACKGROUND:Readmission has received attention as a potential healthcare quality metric. No studies have investigated the relationship between readmission and survival in patients undergoing rectal cancer surgery. The aims of this study were to identify factors associated with 30-day readmission after rectal cancer surgery and to determine the impact of readmission on overall survival (OS). METHODS:Patients who underwent surgical treatment for rectal/rectosigmoid adenocarcinoma stages I-IV were identified using the National Cancer Database (2004-2014). Multivariable logistic regression was used to identify factors for readmission. 2:1 nearest neighbor caliper matching without replacement was used to ensure similarity of patients being compared. Survival analyses were performed using Kaplan-Meier method along with log-rank test and Cox proportional hazards model. RESULTS:Of 110,167 patients, 7045 (6.39%) were readmitted. Factors associated with readmission included higher Charlson comorbidity score, non-private or no insurance, procedure type, hospitals in the Northeast, South, and Midwest regions, and prolonged length of stay. Within the matched cohort (13,756 non-readmitted and 6878 readmitted), readmitted patients had worse 5- and 10-year OS regardless of cancer stage (p < 0.001) and procedure type. Five- and 10-year OS were 58.98% and 41.01% for readmitted patients, 64.96% and 43.50% for non-readmitted patients. Readmitted patients had shorter OS by 13.14 months and increased risk of mortality (HR 1.20, 95% CI 1.15-1.25, p < 0.001). CONCLUSIONS:Thirty-day readmission after rectal cancer surgery is associated with decreased OS. Efforts to reduce readmissions should be considered to advance cancer care and enhance the potential for improved patient survival.

BACKGROUND:Despite recent enthusiasm for the use of laparoscopic liver resection, data evaluating costs associated with laparoscopic liver resections are lacking. We sought to examine the use of laparoscopic liver surgery, and investigate variations in cost among hospitals performing these procedures. METHODS:A nationally representative sample of 12,560 patients who underwent a liver resection in 2012 was identified. Multivariable analyses were performed to compare outcomes associated with liver resection. RESULTS:Among the 12,560 patients who underwent liver resection, 685 (5.4%) underwent a laparoscopic liver resection. The proportion of liver resections performed laparoscopically varied among hospitals ranging from 4.6% to 20.0%; the median volume of laparoscopic liver resections was 10 operations/year. Although laparoscopic surgery was associated with lower postoperative morbidity (aOR = 0.60, 95%CI: 0.36-0.99) and shorter lengths of stay [(LOS) aIRR = 0.83, 95%CI: 0.70-0.97], it was not associated with inpatient mortality (p = 0.971) or hospital costs (p = 0.863). Costs associated with laparoscopic liver resection varied ranging from $5,907 (95%CI: $5,140-$6,674) to $67,178 (95%CI: $66,271-$68,083). The observed variations between hospitals were due to differences in morbidity (coefficient: $20,415, 95%CI: $16,000-$24,830) and LOS (coefficient: $24,690, 95%CI: $21,688-$27,692). CONCLUSIONS:Although laparoscopic liver resection was associated with improved short-term perioperative clinical outcomes, utilization of laparoscopic liver resection remains low.

BACKGROUND & AIMS:Intraductal papillary mucinous neoplasms (IPMNs) are lesions that can progress to invasive pancreatic cancer and constitute an important system for studies of pancreatic tumorigenesis. We performed comprehensive genomic analyses of entire IPMNs to determine the diversity of somatic mutations in genes that promote tumorigenesis. METHODS:We microdissected neoplastic tissues from 6-24 regions each of 20 resected IPMNs, resulting in 227 neoplastic samples that were analyzed by capture-based targeted sequencing. Somatic mutations in genes associated with pancreatic tumorigenesis were assessed across entire IPMN lesions, and the resulting data were supported by evolutionary modeling, whole-exome sequencing, and in situ detection of mutations. RESULTS:We found a high prevalence of heterogeneity among mutations in IPMNs. Heterogeneity in mutations in KRAS and GNAS was significantly more prevalent in IPMNs with low-grade dysplasia than in IPMNs with high-grade dysplasia (P < .02). Whole-exome sequencing confirmed that IPMNs contained multiple independent clones, each with distinct mutations, as originally indicated by targeted sequencing and evolutionary modeling. We also found evidence for convergent evolution of mutations in RNF43 and TP53, which are acquired during later stages of tumorigenesis. CONCLUSIONS:In an analysis of the heterogeneity of mutations throughout IPMNs, we found that early-stage IPMNs contain multiple independent clones, each with distinct mutations, indicating their polyclonal origin. These findings challenge the model in which pancreatic neoplasms arise from a single clone. Increasing our understanding of the mechanisms of IPMN polyclonality could lead to strategies to identify patients at increased risk for pancreatic cancer.

Pancreatic cancer is a lethal disease in a large part due to the systemic nature at the time of diagnosis. In those patients who undergo a potentially curative resection of pancreatic cancer, the overwhelming majority will have systemic relapse. Circulating tumor cells are an important mediator of the development of metastases. Circulating tumor cells have been identified in patients with clinically localized resectable pancreatic cancer and exist as several phenotypes. Mesenchymal and stem cell-like phenotypes of circulating tumor cells predict early recurrence and worse survival. This review focuses on the current understanding of circulating tumor cells in pancreatic cancer and how this information can be used in developing more effective therapy in the future.

PURPOSE:Myeloid cells are a prominent immunosuppressive component within the stroma of pancreatic ductal adenocarcinoma (PDAC). Previously, targeting myeloid cells has had limited success. Here, we sought to target the myeloid cells through modifying a specific stromal component. EXPERIMENTAL DESIGN:A murine model of metastatic PDAC treated with an irradiated whole-cell PDAC vaccine and PDAC specimens from patients treated with the same type of vaccine were used to assess the immune-modulating effect of stromal hyaluronan (HA) degradation by PEGPH20. RESULTS:effector memory T-cell infiltration, an increase in tumor-specific IFNγ, and improved survival. In the stroma of human PDACs treated with the same vaccine, decreased stromal CXCR4 expression significantly correlated with decreased HA and increased cytotoxic activities, suggesting CXCR4 is an important therapeutic target. CONCLUSIONS:This study represents the first to dissect signaling cascades following PDAC stroma remodeling via HA depletion, suggesting this not only overcomes a physical barrier for immune cell trafficking, but alters myeloid function leading to downstream selective increases in effector memory T-cell infiltration and antitumor activity.

INTRODUCTION/BACKGROUND:The incidence, timing, and implications of recurrence in patients who underwent neoadjuvant treatment and surgical resection of borderline resectable (BRPC) or locally advanced (LAPC) pancreatic cancer are not well established. MATERIALS AND METHODS/METHODS:Patients with BRPC/LAPC who underwent post-neoadjuvant resection between 2007 and 2015 were included. Associations between clinicopathologic characteristics and specific recurrence locations, recurrence-free survival (RFS), and overall survival from resection (OS) were assessed using Cox regression analyses. RESULTS:For 231 included patients, median survival from diagnosis and resection were 28.0 and 19.8 months, respectively. After a median RFS of 7.9 months, 189 (81.8%) patients had recurred. Multiple-site (n = 87, 46.0%) and liver-only recurrence (n = 28, 14.8%) generally occurred earlier and resulted in significantly worse OS when compared to local-only (n = 52, 27.5%) or lung-only recurrence (n = 18, 9.5%). Microscopic perineural invasion, yN1-yN2 status and elevated pre-surgery CA 19-9 >100 U/mL were associated with both local-only and multiple-site/liver-only recurrence. R1-margin was associated with local-only recurrence (HR 2.03). yN1-yN2 status and microscopic perineural invasion were independent predictors for both poor RFS and OS, while yT3-yT4 tumor stage (HR 1.39) and poor tumor differentiation (HR 1.60) were only predictive of poor OS. Adjuvant therapy was independently associated with both prolonged RFS (HR 0.73; median 7.0 vs. 10.9 months) and OS (HR 0.69; median 15.4 vs. 22.7 months). CONCLUSION/CONCLUSIONS:Despite neoadjuvant therapy leading to resection and relatively favorable pathologic tumor characteristics in BRPC/LAPC patients, more than 80% of patients experienced disease recurrence, 72.5% of which occurred at distant sites.