Faculty Bibliography

Pancreatic cancer is caused by inherited and acquired mutations in specific cancer-associated genes. The discovery of the most common genetic alterations in pancreatic cancer has provided insight into the fundamental pathways that drive the progression from a normal cell to noninvasive precursor lesions and finally to widely metastatic disease. In addition, recent genetic discoveries have created new opportunities to develop gene-based approaches for early detection, personalized treatment, and molecular classification of pancreatic neoplasms.

OBJECTIVES: Management of liver metastasis (LM) from a non-colorectal, non-neuroendocrine primary carcinoma remains controversial. Few data exist on the management of hepatic metastasis from primary renal cell carcinoma (RCC). This study sought to determine the safety and efficacy of surgery for RCC LM. METHODS: A total of 43 patients who underwent surgery for RCC hepatic metastasis between 1994 and 2011 were identified in a multi-institution hepatobiliary database. Clinicopathologic, operative and outcome data were collected and analysed. RESULTS: Mean patient age was 62.4 years and most patients (67.4%) were male. The mean tumour size of the primary RCC was 6.9 cm and most tumours (72.1%) were designated as clear cell carcinoma. Nine patients (20.9%) presented with synchronous LM. Among the patients with metachronous disease, the median time from diagnosis of the primary RCC to treatment of LM was 17.2 months (range: 2.1-189.3 months). The mean size of the RCC LM was 4.0 cm and most patients (55.8%) had a solitary metastasis. Most patients (86.0%) underwent a minor resection (up to three segments). Final pathology showed margin status to be negative (R0) in 95.3% of patients. Postoperative morbidity was 23.3% and there was one perioperative death. A total of 69.8% of patients received perioperative chemotherapy. Overall 3-year survival was 62.1%. Three-year recurrence-free survival was 27.3% and the median length of recurrence-free survival was 15.5 months. CONCLUSIONS: Resection of RCC hepatic metastasis is safe and is associated with low morbidity and near-zero mortality. Although recurrence occurs in up to 50% of patients, resection can be associated with long-term survival in a well-selected subset of patients.

Pancreatic neuroendocrine tumors with prominent stromal fibrosis are often clinically, radiographically, and grossly indistinguishable from ductal adenocarcinoma. We recently described a small series of fibrotic pancreatic neuroendocrine tumors that express serotonin. To understand better the relationship between histopathologic patterns and serotonin expression, we reviewed 361 pancreatic neuroendocrine tumors to identify those with prominent stromal fibrosis exceeding 30% of total tumor area. We identified 52 cases and immunolabeled these neoplasms with antibodies to serotonin and Ki-67. Two predominant histologic subtypes were identified: 14 (26.9%) of 52 had a trabecular or trabecular-glandular cellular pattern with interspersed fibrosis, whereas 38 (73.1%) of 52 had solid architecture. Of the 52, 14 (26.9%) pancreatic neuroendocrine tumors showed at least focal serotonin immunoreactivity. Tumors with predominantly trabecular architecture were significantly more likely to express serotonin than those with solid architecture (P < .01). Only 2 of 34 pancreatic neuroendocrine tumors with fibrosis less than 30% of total tumor area expressed serotonin. The 14 serotonin-expressing tumors were less likely to have lymph node metastases (P = .016) and more likely to involve large pancreatic ducts (P < .01) than were the 38 serotonin-negative tumors. The serotonin-expressing tumors were also found in a younger patient population (P < .01). There was no significant association of serotonin immunoreactivity with Ki-67 proliferation index, tumor size, or distant metastases. Our data demonstrate a strong correlation between trabecular architecture and serotonin immunoreactivity in pancreatic neuroendocrine tumors with stromal fibrosis. Serotonin-expressing tumors are also less likely to have lymph node metastases and more likely to involve large pancreatic ducts.

INTRODUCTION/BACKGROUND:Assessing patient-specific risk factors for long-term mortality following resection of pancreatic adenocarcinoma can be difficult. Sarcopenia--the measurement of muscle wasting--may be a more objective and comprehensive patient-specific factor associated with long-term survival. METHODS:Total psoas area (TPA) was measured on preoperative cross-sectional imaging in 557 patients undergoing resection of pancreatic adenocarcinoma between 1996 and 2010. Sarcopenia was defined as the presence of a TPA in the lowest sex-specific quartile. The impact of sarcopenia on 90-day, 1-year, and 3-year mortality was assessed relative to other clinicopathological factors. RESULTS:Mean patient age was 65.7 years and 53.1 % was male. Mean TPA among men (611 mm²/m²) was greater than among women (454 mm²/m²). Surgery involved pancreaticoduodenectomy (86.0 %) or distal pancreatectomy (14.0 %). Mean tumor size was 3.4 cm; 49.9 % and 88.5 % of patients had vascular and perineural invasion, respectively. Margin status was R0 (59.0 %) and 77.7 % patients had lymph node metastasis. Overall 90-day mortality was 3.1 % and overall 1- and 3-year survival was 67.9 % and 35.7 %, respectively. Sarcopenia was associated with increased risk of 3-year mortality (HR = 1.68; P < 0.001). Tumor-specific factors such as poor differentiation on histology (HR = 1.75), margin status (HR = 1.66), and lymph node metastasis (HR = 2.06) were associated with risk of death at 3-years (all P < 0.001). After controlling for these factors, sarcopenia remained independently associated with an increased risk of death at 3 years (HR = 1.63; P < 0.001). CONCLUSIONS:Sarcopenia was a predictor of survival following pancreatic surgery, with sarcopenic patients having a 63 % increased risk of death at 3 years. Sarcopenia was an objective measure of patient frailty that was strongly associated with long-term outcome independent of tumor-specific factors.

The overall 5 year survival rate for pancreatic ductal adenocarcinoma (i.e., PDAC) is a dismal 5%, although patients that have undergone surgical resection have a somewhat better survival rate of up to 20%. Very long-term survivors of PDAC (defined as patients with ≥ 10 year survival following apparently curative resection), on the other hand, are considerably less frequent. The molecular characteristics of very long-term survivors (VLTS) are poorly understood, but might provide novel insights into prognostication for this disease. In this study, a panel of five VLTS and stage-matched short-term survivors (STS, defined as disease-specific mortality within 14 months of resection) were identified, and quantitative proteomics was applied to comparatively profile tumor tissues from both cohorts. Differentially expressed proteins were identified in cancers from VLTS vs. STS patients. Specifically, the expression of galectin-1 was 2-fold lower in VLTS compared with STS tumors. Validation studies were performed by immunohistochemistry (IHC) in two additional cohorts of resected PDAC, including: 1) an independent cohort of VLTS and 2) a panel of sporadic PDAC with a considerable range of overall survival following surgery. Immunolabeling analysis confirmed that significantly lower expression of stromal galectin-1 was associated with VLTS (p = 0.02) and also correlated with longer survival in sporadic, surgically-treated PDAC cases (hazard ratio = 4.9, p = 0.002). The results from this study provide new insights to better understand the role of galectin-1 in PDAC survival, and might be useful for rendering prognostic information, and developing more effective therapeutic strategies aimed at improving survival.

OBJECTIVE:This pictorial essay reviews the imaging appearance of pancreatic neuroendocrine tumors, as well as a number of mimics on CT. CONCLUSION/CONCLUSIONS:Pancreatic neuroendocrine tumors have a distinct appearance, typically characterized by a well-defined hypervascular mass best visualized on arterial phase images. However, a number of other lesions can mimic the CT appearance of pancreatic neuroendocrine tumors, including pancreatic metastases, acinar cell carcinoma, pancreatoblastoma, solitary fibrous tumor, pancreatic hamartoma, serous adenoma, intrapancreatic splenules, exophytic gastrointestinal stromal tumors, and peripancreatic paragangliomas.

BACKGROUND AND PURPOSE/OBJECTIVE:This study seeks to: (a) quantify radiologic-pathologic discrepancy for pancreatic adenocarcinoma by comparing tumor size on conventional computed tomography (C-CT) and 3-dimensional CT (3D-CT) to corresponding pathologic specimens; and (b) to identify clinico-pathologic characteristics predictive of radiologic-pathologic discrepancy to assist radiotherapy planning. MATERIALS AND METHODS/METHODS:Sixty-three patients with pancreatic adenocarcinoma and preoperative C-CT and volume-rendered 3D-CT imaging within 6 weeks of resection were identified. Maximum tumor diameter (MTD) was measured on pathology, C-CT, and 3D-CT and compared for each patient as well as among different clinico-pathologic subgroups. RESULTS:There was a trend toward C-CT underestimation of MTD compared to final pathology (p=0.08), but no significant difference between 3D-CT MTD and pathology (p=0.54). Pathologic tumor size was significantly underestimated by C-CT in patients with larger pathologic tumor size (>3.0 cm, p=0.0001), smaller tumor size on C-CT (<3.0 cm, p=0.003), higher CA19-9 (>90 U/mL, p=0.008), and location in the pancreatic head (p=0.015). A model for predicting pathologic MTD using C-CT MTD and CA19-9 level was generated. CONCLUSIONS:3D-CT may allow for more accurate contouring of pancreatic tumors than C-CT. Patients with the above clinico-pathologic characteristics may require expanded margins relative to tumor size estimates on C-CT during radiotherapy planning.

PURPOSE/OBJECTIVE:The purpose of this study is to identify factors predictive of early mortality following palliative bypass in patients with previously unsuspected advanced pancreatic adenocarcinoma to provide a basis for the selection of appropriate therapies. METHODS:All patients with pancreatic adenocarcinoma who underwent a bypass procedure at our institution between 9/30/1994 and 1/31/2006 were reviewed. Patients with peri-operative mortality were excluded from the analysis. Univariate analysis was performed on peri-operative data to identify factors associated with early mortality (death within 6 months of surgery). Patients having multiple risk factors were assigned an overall prognostic score based on the sum of these factors. RESULTS:Of the 397 patients with pancreatic adenocarcinoma analyzed, four factors were found to predict early mortality following palliative bypass: Presence of distant metastatic disease (HR 2.59, P < 0.0001), poor tumor differentiation (HR 1.71, P = 0.009), severe pre-operative nausea and vomiting (HR 1.48, P = 0.013), and lack of previous placement of a biliary stent (HR 1.36, P = 0.048). Patients with a prognostic score of 0 were significantly more likely to survive past 6 months than patients with a prognostic score of 1 (HR 2.71, P < 0.0001), 2 (HR 3.70, P < 0.0001), or ≥3 (HR 5.63, P < 0.0001). CONCLUSIONS:In a cohort of patients undergoing a palliative bypass procedure, specific peri-operative factors can be used to identify patients who are at risk of early mortality. These factors may be helpful in selecting appropriate interventions for this group of patients.

Approximately 45% of sporadic well-differentiated pancreatic neuroendocrine tumors harbor mutations in either ATRX (alpha thalassemia/mental retardation X-linked) or DAXX (death domain-associated protein). These novel tumor suppressor genes encode nuclear proteins that interact with one another and function in chromatin remodeling at telomeric and peri-centromeric regions. Mutations in these genes are associated with loss of their protein expression and correlate with the alternative lengthening of telomeres phenotype. Patients with multiple endocrine neoplasia-1 (MEN-1) syndrome, genetically defined by a germ line mutation in the MEN1 gene, are predisposed to developing pancreatic neuroendocrine tumors and thus represent a unique model for studying the timing of ATRX and DAXX inactivation in pancreatic neuroendocrine tumor development. We characterized ATRX and DAXX protein expression by immunohistochemistry and telomere status by telomere-specific fluorescence in situ hybridization in 109 well-differentiated pancreatic neuroendocrine lesions from 28 MEN-1 syndrome patients. The study consisted of 47 neuroendocrine microadenomas (<0.5 cm), 50 pancreatic neuroendocrine tumors (≥0.5 cm), and 12 pancreatic neuroendocrine tumor lymph node metastases. Expression of ATRX and DAXX was intact in all 47 microadenomas, and none showed the alternative lengthening of telomeres phenotype. ATRX and/or DAXX expression was lost in 3 of 50 (6%) pancreatic neuroendocrine tumors. In all three of these, tumor size was ≥3 cm, and loss of ATRX and/or DAXX expression correlated with the alternative lengthening of telomeres phenotype. Concurrent lymph node metastases were present for two of the three tumors, and each metastasis displayed the same changes as the primary tumor. These findings establish the existence of ATRX and DAXX defects and the alternative lengthening of telomeres phenotype in pancreatic neuroendocrine tumors in the context of MEN-1 syndrome. The observation that ATRX and DAXX defects and the alternative lengthening of telomeres phenotype occurred only in pancreatic neuroendocrine tumors measuring ≥3 cm and their lymph node metastases suggests that these changes are late events in pancreatic neuroendocrine tumor development.

BACKGROUND:Duodenal adenocarcinoma is a rare cancer usually studied as a group with periampullary or small bowel adenocarcinoma; therefore, its natural history is poorly understood. METHODS:Patients with duodenal adenocarcinoma were identified from a single-institution pancreaticoduodenectomy database. Patients with adenocarcinoma arising from the ampulla of Vater were excluded. Univariate and multivariate analyses were performed to identify clinicopathologic variables associated with survival and recurrence after resection. RESULTS:From 1984 to 2006, a total of 122 patients with duodenal adenocarcinoma underwent pancreaticoduodenectomy. Overall survival after resection was 48% at 5 years and 41% at 10 years. Five-year survival decreased as the number of lymph nodes involved by metastasis increased from 0 to 1-3 to ≥ 4 (68%, 58%, 17%, respectively, P < 0.01) and as the lymph node ratio increased from 0 to >0-0.2 to >0.2-0.4 to >0.4 (68%, 57%, 14%, 14%, respectively, P < 0.01). Lymph node metastasis was the only independent predictor of decreased survival in multivariate analysis. Recurrence after resection was predominantly distant (81%). Adjuvant chemoradiation did not decrease local recurrence or prolong overall survival; however, patients who received chemoradiation more commonly had nodal metastasis (P = 0.03). CONCLUSIONS:The prognostic significance of both the absolute number and ratio of involved lymph nodes emphasizes the need for adequate lymphadenectomy to accurately stage duodenal adenocarcinoma. The mostly distant pattern of recurrence underscores the need for the development of effective systemic therapies.