Long-term follow-up experience with adjuvant therapy after irreversible electroporation of locally advanced pancreatic cancer.

BACKGROUND: Irreversible electroporation (IRE) expands the surgical options for patients with unresectable pancreatic cancer. This study evaluated for differences in survival stratified by type of IRE and receipt of adjuvant chemotherapy. METHODS: Patients with locally advanced pancreatic cancer treated by IRE (2012-2020) were retrospectively included. Overall survival (OS) and recurrence-free survival (RFS) were compared by type of IRE (in situ for local tumor control or IRE of potentially positive margins with resection) and by receipt of adjuvant chemotherapy. RESULTS: Thirty-nine patients had IRE in situ, 61 had IRE for margin extension, and 19 received adjuvant chemotherapy. Most (97.00%) underwent induction chemotherapy. OS was 28.71 months (interquartile range [IQR] 19.17, 51.19) from diagnosis, with no difference by IRE type (hazard ratio [HR] 1.05 for margin extension [p = 0.85]) or adjuvant chemotherapy (HR 1.14 [p = 0.639]). RFS was 8.51 months (IQR 4.95, 20.17) with no difference by IRE type (HR 0.90 for margin extension [p = 0.694]) or adjuvant chemotherapy (HR 0.90 [p = 0.711]). CONCLUSION: These findings suggest that adjuvant therapy may have limited benefit for patients treated with induction chemotherapy followed by local control with IRE for unresectable pancreatic cancer. Further study of the duration and timing of systemic therapy is warranted to maximize benefit and limit toxicity.

Perioperative and persistent opioid utilization following pancreatectomy in the United States.

BACKGROUND: Opioids are central to analgesia for pancreatic diseases. Individuals undergoing pancreatectomy have largely been excluded from studies of opioid use, because of malignancy or chronic use. Surgeons need to understand usage patterns, and practices that may incline patients toward persistent post-operative use. METHODS: A retrospective study using IBM Watson Health MarketScan database examined patterns of peri-pancreatectomy opioid use between 2009 and 2017. Patients were grouped by opioid use 12 months to 31 days prior to pancreatectomy and followed for persistent use (refills 90-180 days postoperatively). Morphine milligram equivalents (MME) were calculated. Multivariable models explored associations between clinical characteristics, perioperative use and persistent use. RESULTS: Opioids were used within the year prior to surgery by 35.6% of 8325 patients. The median MME for opioid naïve patients (400 mg) was a fraction of the 1800 mg prescribed to chronic opioid users for peri-operative analgesia. The rate of persistent opioid use was 15.1% among naïve, 27.2% among intermittent and 77.3% among chronic opioid users. Multivariable models demonstrated naïve and intermittent users who filled a prescription within 30 days prior to pancreatectomy, those who were prescribed total MME ≥1500 mg, and a ≥14 day supply were most at risk of persistent opioid use. Almost 23% of chronic users stopped using opioids post-operatively, suggesting surgery can provide relief. CONCLUSION: Preoperative and persistent opioid use after pancreatectomy is substantially greater than expected based on other operations. Providers may mitigate this by recognizing the issue, managing expectations, and altering the timing and quantities of opioids prescribed.

Long term quality of life amongst pancreatectomy patients with diabetes mellitus.

BACKGROUND: Pancreatogenic diabetes is common after pancreatectomy, and the impact on quality of life (QOL) is poorly understood. The objective of this study was to investigate QOL between diabetic and non-diabetic patients at least five years after pancreatectomy. METHODS: Patients were recruited from a prospectively maintained institutional database. Participants were administered the Audit of Diabetes-Dependent Quality of Life (ADDQOL). Quality of life was compared between diabetics and non-diabetics using validated European Organization for Research and Treatment of Cancer questionnaires. RESULTS: 80 individuals completed surveys. 55% were female, 80% non-Hispanic white, 44% underwent Whipple, 48% were cystic neoplasms and 39% were adenocarcinoma. Diabetic patients (42.5%) reported comparable EORTC QLQ-C30 and Pan26 scores to non-diabetic patients. Pre-operative diabetic patients reported more dyspnea (p = 0.02) and greater pain (p = 0.02) than new-onset diabetics. Diabetic patients reported an overall ADDQOL quality of life score 'very good' (IQR: excellent, good) though felt life would be much better without diabetes (IQR: very much better, little better). While operation type was not influential, patients diagnosed with cystic neoplasms were almost twice as likely as those with other pathologies to report that life would be much better without diabetes (p < 0.01). CONCLUSION: At a median of 9.3 years from pancreatic surgery, ADDQoL scores of patients were similar to cohorts of non-pancreatogenic diabetics in the general population. Patients without cancer were more likely to report that diabetes affected their overall QOL, regardless of operation. This study provides nuanced understanding of long-term QOL to improve the informed consent process and post-operative long-term care.

Long-term health after pancreatic surgery: the view from 9.5 years.

BACKGROUND: Discussing the impact of pancreatic surgery on long-term health is poorly understood, but necessary for informed consent. Given the increased number of pancreatic operations being performed annually, further investigation is necessary. METHODS: Patients surviving longer than 5 years after pancreatic surgery were surveyed for postoperative hospitalizations, operations, pain, nutrition and diabetes. Variables were analyzed according to patient and peri-operative variables, and validated using medical records. RESULTS: Eighty individuals completed the survey; median follow-up was 9.5 years (IQR:6.43,12.73). 47.5% underwent a pancreatoduodenectomy, and 25.0% a distal pancreatectomy; 40.0% had adenocarcinoma. 57.1% reported long-term weight loss, of which 65.9% was unintentional. While 1.3% took pancreatic enzymes before surgery, 38.8% utilized after. 12.5% had diabetes before, and 28.6% after surgery; 22 of 30 patients required insulin replacement therapy (73.3%). 41.3% reported hospitalizations, 17.5% required endoscopies and 28.8% additional operations after full recovery. Need for additional interventions were not related to pathology or post-operative complications, but were more common among patients undergoing a Whipple. CONCLUSION: More than half of patients will have a long-term medical complication attributable to pancreatectomy. In comparison to the literature, it may be inferred that consequences occur within the first few years after surgery, and do not compound over time.

New onset diabetes predicts progression of low risk pancreatic mucinous cysts.

BACKGROUND: Patients with low-risk lesions require ongoing surveillance since the rate of progression to pancreatic cancer (PC), while small, is much greater than in the general population. Our objective was to study the relationship between new onset diabetes (NODM) and progression in patients with low risk mucinous cysts. METHODS: We evaluated a prospectively maintained cohort of 442 patients with a suspected mucinous cyst without worrisome features (WF) or high-risk stigmata (HRS). Multivariable Cox models were developed for progression to WF and HRS, with diabetes status formulated as both time independent and dependent covariates. The adjusted cumulative risk of progression was calculated using the corrected group prognosis method. RESULTS: The 5-year cumulative progression rates to WFs and HRS were 12.8 and 3.6%, respectively. After controlling for other risk factors, the development of NODM was strongly associated with progression to HRS (HR = 11.6; 95%CI, 3.5-57.7%), but not WF. Among patients with the smallest cysts (<10 mm) at baseline, those who developed NODM had a 5-year adjusted cumulative risk of progression to HRS of 8.6% (95%CI, 0.0%-20.2%), compared to only 0.8% (95%CI, 0.0%-2.3%) for patients without NODM. Among patients with the largest cysts (20-29 mm), those who developed NODM during surveillance had a 5-year adjusted cumulative risk of progression of 53.5% (95%CI, 19.6%-89.9%) compared to only 7.5% (95%CI, 1.6%-15.2%) for patients without NODM. CONCLUSION: New onset diabetes may predict progression in patients with low risk mucinous cysts. Pending validation with large-scale studies, these findings support regular diabetes screening among patients surveilled for suspected IPMNs or MCNs.

Long-Term Surveillance and Timeline of Progression of Presumed Low-Risk Intraductal Papillary Mucinous Neoplasms.

OBJECTIVE: The purpose of this study was to assess risk of progression and rate of growth of presumed low-risk branch duct intraductal papillary mucinous neoplasms surveyed for more than 4 years. MATERIALS AND METHODS: A keyword search of electronic medical charts was performed for the years 2001-2013. Cystic lesions that met the criteria for clinical branch duct intraductal papillary mucinous neoplasm, lacked baseline high-risk or worrisome features, and had more than 4 years of surveillance were included in this study. Two radiologists performed cyst size measurements to assess interreader variability. Cyst progression was defined either as 2-mm or greater or 20% or greater increase in diameter or as development of worrisome features. Kaplan-Meier curves were generated to evaluate cyst progression time and linear mixed models to evaluate growth rates. RESULTS: The search revealed 2423 patients with cystic pancreatic lesions. Among these patients 228 had imaging follow-up for 4 or more years, and 131 met the clinical criteria for branch duct intraductal papillary mucinous neoplasms. Among the 131 cysts, 73 (55.7%) progressed: 61 (46.6%) increased in size, 10 (7.6%) increased in size and developed worrisome features, and two (1.5%) developed worrisome features only. Of the 71 cysts that increased in size, 50 (70.4%) did so within the first 5 years, and 21 (29.6%) grew after 5 years. No patient had adenocarcinoma. There was no significant difference in growth rate based on cyst size within the first 50 months. After 50 months, cysts larger than 20 mm continued to increase in size (p < 0.05) and had faster growth rates. CONCLUSION: Among presumed low-risk branch duct intraductal papillary mucinous neoplasms, most increased in size, approximately 30% after 5 years. Cysts with baseline size larger than 20 mm continued to grow beyond 5 years at a faster rate.

Single-Institution Experience with Irreversible Electroporation for T4 Pancreatic Cancer: First 50 Patients.

BACKGROUND: Irreversible electroporation (IRE) for treatment of locally advanced pancreatic tumors is garnering increasing attention. This study was conducted to determine perioperative morbidity and mortality for locally advanced pancreatic cancer. METHODS: Prospective data of 50 consecutive patients receiving IRE for T4 lesions at a single tertiary center were analyzed. The primary end point was Clavien-Dindo complications at 90 days, and the secondary outcomes were survival and recurrence. RESULTS: A total of 50 patients underwent 53 IRE procedures for primary treatment (n = 29) or margin extension (n = 24), and 47 patients had adenocarcinoma. Six patients died within 90 days after the procedure (5 in the primary control group). Mortality occurred a median of 26 days (range, 8-42 days) after the procedure. Five patients in both the margin-extension and primary control groups experienced grade 3 or 4 morbidity (p = 0.739). The incidences of grades 3 to 5 complications did not differ significantly based on the adjustable parameters of IRE, tumor size, or primary treatment versus margin extension. After a median follow-up period of 8.69 months [interquartile range (IQR), 0.26-16.26 months], the median overall survival period for the primary control group was 7.71 months [95 % confidence interval (CI), 6.03-12.0 months) and was not reached in the margin-extension group (p = 0.01, log-rank). CONCLUSIONS: At the authors' center, the mortality rate after IRE was higher than reported in other series, with the majority occurring in the primary control group. Major morbidity trended around upper gastrointestinal bleeding, visceral ulcerations/perforations, and portal vein thromboses. This favors further investigation of the safety and efficacy of IRE.

Evolving Technique for Puestow-Type Procedure for Chronic Pancreatitis: The Combined Roux-en-Y Proximal End-to-Side and Distal Longitudinal Pancreatojejunostomy.

BACKGROUND The goal of surgical procedures in chronic pancreatitis is to establish drainage of the duct throughout the gland as well as resect any inflammatory masses if present. Conventionally, for patients with a dilated pancreatic duct without inflammatory masses, a drainage procedure in the form of a longitudinal pancreatojejunostomy (or Partington-Rochelle modification of the Puestow procedure) is the procedure of choice. CASE REPORT In present case, a patient with chronic pancreatitis was evaluated for surgical management, but extensive intraductal and parenchymal pancreaticolithiasis throughout the entire gland considerably restricted access to the duct. A novel combined Roux-en-Y partial longitudinal pancreatojejunostomy of the body and tail with an end-to-side pancreatojejunostomy of the head was fashioned to facilitate drainage of the entire pancreas, without resection of any parenchyma. The patient's immediate postoperative course was uncomplicated, and at her 30-day follow-up, she had been without pain and had been tolerating a diet, with additional pancreatic enzyme supplementation. CONCLUSIONS Roux-en-Y partial longitudinal pancreatojejunostomy (or modified Puestow procedure) should be considered a viable option for the surgical management of chronic pancreatitis with extensive pancreaticolithiasis, with good short-term outcomes. It underscores the importance of leveraging anatomic limitations to expand the choice of drainage procedure for chronic pancreatitis. This procedure should be considered in those patients with significant pancreaticolithiasis, where clear visualization of the main pancreatic duct is limited, precluding a lengthy pancreatojejunostomy.

Readmission after pancreatic resection is not an appropriate measure of quality.

BACKGROUND: Hospital readmission has been proposed as a metric for quality of medical and surgical care. We examined our institutional experience with readmission after pancreatic resection, and assessed factors predictive of readmission. METHODS: We reviewed 787 pancreatic resections performed at a single institution between 2006 and 2010. Univariate and multivariate logistic regression models were used to assess the relationships between preoperative and postoperative characteristics and readmission. Reasons for hospital readmission were examined in detail. RESULTS: We found the 30-day readmission rate after pancreatic resection to be 11.6 %. In univariate analysis, young age, pancreaticoduodenectomy versus other operations, open versus laparoscopic technique, fistula formation, the need for reoperation, and any complication during the index hospitalization were predictive of readmission. In multivariate analysis, only young age and postoperative complication were predictive of readmission. Vascular resection, postoperative ICU care, length of stay, and discharge disposition were not associated with readmission. The most common reasons for readmission were leaks, fistulas, abscesses, and wound infections (45.1 %), delayed gastric emptying (12.1 %), venous thrombosis (7.7 %), and GI bleeding (7.7 %). CONCLUSIONS: We found the vast majority of readmissions after pancreatic resection were to manage complications related to the operation and were not due to poor coordination of care or poor discharge planning. Because evidence-based measures to prevent these surgical complications do not exist, we cannot support the use of readmission rates themselves as a quality indicator after pancreatic surgery.

Associations Between Patient Characteristics and Whipple Procedure Outcomes Before and After Implementation of an Enhanced Recovery After Surgery Protocol.

PURPOSE: The Enhanced Recovery After Surgery (ERAS) protocol is a multimodal perioperative care bundle aimed to improve pancreatic surgery outcomes. This work evaluates whether a Whipple ERAS protocol can be safely implemented at a quaternary care center. We also aimed to assess if race and socioeconomic factors are associated with disparities in outcomes in patients undergoing a Whipple ERAS protocol. METHODS: A retrospective review identified demographic and clinical data for 458 patients undergoing pancreaticoduodenectomies (PDs) at a single institution from October 2017 to May 2022. Patients were split into two cohorts: pre-ERAS (treated before implementation) and ERAS (treated after). Outcomes included length of stay (LOS), 30-day readmission and mortality rates, and major complications. RESULTS: There were 213 pre-ERAS PD patients, and 245 were managed with an ERAS protocol. More ERAS patients had a BMI > 30 (15.5% vs. 8.0%; p = 0.01) and received neoadjuvant chemotherapy (15.5% vs. 4.2%; p < 0.001). ERAS patients had a higher rate of major complications (57.6% vs. 37.6%; p < 0.001). Medicaid patients did not have more complications or longer LOS compared to non-Medicaid patients. On univariate analysis, race/ethnicity or gender was not significantly associated with a higher rate of major complications or prolonged LOS. CONCLUSION: A Whipple ERAS protocol did not significantly change LOS, readmissions, or 30-day mortality. Rate of overall complications did not significantly change after implementation, but rate of major complications increased. These outcomes were not significantly impacted by race/ethnicity, gender, tumor staging, or insurance status.

Socioeconomic Predictors of Access to Care for Patients with Operatively Managed Pancreatic Cancer in New York State.

PURPOSE: We evaluated how race and socioeconomic factors impact access to high-volume surgical centers, treatment initiation, and postoperative care for pancreatic cancer in a state with robust safety net insurance coverage and healthcare infrastructure. METHODS: The New York Statewide Planning and Research Cooperative System was analyzed. Patients with pancreatic cancer resected from 2007 to 2017 were identified by ICD and CPT codes. Primary outcomes included surgery at low-volume facilities (< 20 pancreatectomies/year), time to therapy initiation, and time to postoperative surveillance imaging (within 60-180 days after surgery). RESULTS: In total, 3312 patients underwent pancreatectomy across 124 facilities. Median age was 67 years (IQR 59, 75) and 55% of patients were male. Most (72.7%) had surgery at high-volume centers. On multivariable analysis, odds ratios for surgery at low-volume centers were increased for Black race (2.21 (95% CI 1.69-2.88)), Asian race (1.64 (95% CI 1.09-2.43)), Hispanic ethnicity (1.68 (95% CI 1.24-2.28)), Medicaid insurance (2.52 (95% CI 1.79-3.56)), no insurance (2.24 (95% CI 1.38-3.61)), lowest income quartile (3.31 (95% CI 2.14-5.32)), and rural zip code (2.49 (95% CI 1.69-3.65)). Patients treated at low-volume centers waited longer to initiate treatment (hazard ratio (HR) 0.91 (95% CI 0.81-1.01)). Black patients underwent the least surveillance imaging (50.4%; p < 0.0001), while Asian (HR 2.04, 95% CI 1.40-2.98)) and Hispanic patients (HR 1.36 (95% CI 1.00-1.84)) were more likely to have surveillance imaging. CONCLUSIONS: Race independently affected access to high-volume facilities and surveillance imaging. When considered in light of other accumulating evidence, future efforts might investigate the perceptions and logistical considerations noted by providers and patients alike to identify the etiology of these disparities and then institute corrective measures.

Prevalence and Risk Factors for Pancreatic Insufficiency After Partial Pancreatectomy.

BACKGROUND: This study aimed to determine the rate, timing, and predictors of diabetes and exocrine pancreatic insufficiency after pancreatectomy in order to inform preoperative patient counseling and risk management strategies. METHODS: Using prescription claims as a surrogate for disease prevalence, IBM Watson Health MarketScan was queried for claims patterns pre- and post-pancreatectomy. Multivariable models explored associations between clinical characteristics and medication use within 2 years of surgery. RESULTS: In total, 18.96% of 2,848 pancreaticoduodenectomy (PD) patients and 18.95% of 1,858 distal pancreatectomy (DP) patients had preoperative diabetic medication prescription claims. Fewer (6.6% and 3.88%, respectively) had pancreatic enzyme replacement therapy (PERT) claims. Diabetic medication claims increased to 28.69% after PD and 38.59% after DP [adjusted relative risk (aRR) = 1.36 (95% CI 1.27, 1.46)]. Other associated factors included age > 45, medical comorbidity, and obesity. The incidence of new diabetic medication claims among medication naïve patients was 13.78% for PD and 24.7% for DP (p < 0.001) with a median 4.7 and 4.9 months post-operatively. The prevalence of PERT claims was 55.97% after PD and 17.06% after DP [aRR = 0.32 (0.29, 0.36)]. The incidence of postoperative PERT claims 53.98% (PD) and 14.84% (DP) (p < 0.0001). The median time to new PERT claim was 3.0 (PD) and 3.2 (DP) months, respectively. Claims for both diabetic medications and PERT rose sharply after surgery and plateaued within 6 months. CONCLUSIONS: This study defines prevalence, timing, and predictors for post-pancreatectomy insufficiency to inform preoperative counseling, risk modification strategies, and interventions related to quality of life.

Review of minimally invasive pancreas surgery and opinion on its incorporation into low volume and resource poor centres.

Pancreatic surgery has been one of the last areas for the application of minimally invasive surgery (MIS) because there are many factors that make laparoscopic pancreas resections difficult. The concept of service centralization has also limited expertise to a small cadre of high-volume centres in resource rich countries. However, this is not the environment that many surgeons in developing countries work in. These patients often do not have the opportunity to travel to high volume centres for care. Therefore, we sought to review the existing data on MIS for the pancreas and to discuss. In this paper, we review the evolution of MIS on the pancreas and discuss the incorporation of this service into low-volume and resource-poor countries, such as those in the Caribbean. This paper has two parts. First, we performed a literature review evaluating all studies published on laparoscopic and robotic surgery of the pancreas. The data in the Caribbean is examined and we discuss tips for incorporating this operation into resource poor hospital practice. Low pancreatic case volume in the Caribbean, and financial barriers to MIS in general, laparoscopic distal pancreatectomy, enucleation and cystogastrostomy are feasible operations to integrate in to a resource-limited healthcare environment. This is because they can be performed with minimal to no consumables and require an intermediate MIS skillset to complement an open pancreatic surgeon's peri-operative experience.

Long-term quality of life and global health following pancreatic surgery for benign and malignant pathologies.

BACKGROUND: While the frequency of pancreatic operations are increasing, understanding quality of life is still insufficient. The aim was to evaluate global health and quality of life of long-term survivors from a range of pancreatic operations using internationally validated instruments. METHODS: Patients surviving longer than 5 years after pancreatic operations were surveyed using the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire Cancer-30 and Pancreatic Cancer-26 modules. Variables were analyzed according to demographic and clinical features. RESULTS: Eighty patients completed questionnaires. The median follow-up was 9.3 years from the time of operation. The mean scores of global health status/quality of life, physical function, role function, emotional function, cognitive function, and social functioning were 73.9, 83.7, 84.6, 81.1, 80.2, and 86.3, respectively. The participants' reported quality of life was comparable or better than the general United States population. The summary score, which was defined as weighted average of function and symptom scores (excluding global health status/quality of life and financial impact scores), showed significant differences according to the level of education (70.1 no college vs 85.2 college and 85.7 grad school, P = .049), operation type (79.9 pancreatoduodenectomy vs 91.1 total, P = .043), additional endoscopic retrograde cholangiopancreatography (77.3 vs 86.0, P = .029), and additional abdominal operations related to the primary operation (79.0 vs 86.6, P = .026). CONCLUSION: Long-term survivors of pancreatectomy had comparable or better global health status/quality of life, function scale, and lower symptom scores than the general population of the United States, though persistent gastrointestinal symptoms are common. These findings should help inform patients of the long-term consequences of pancreatectomy, so they can make better decisions especially when considering prophylactic operations.

Arguments against the Requirement of a Biological License Application for Human Pancreatic Islets: The Position Statement of the Islets for US Collaborative Presented during the FDA Advisory Committee Meeting.

The Food and Drug Administration (FDA) has been regulating human islets for allotransplantation as a biologic drug in the US. Consequently, the requirement of a biological license application (BLA) approval before clinical use of islet transplantation as a standard of care procedure has stalled the development of the field for the last 20 years. Herein, we provide our commentary to the multiple FDA's position papers and guidance for industry arguing that BLA requirement has been inappropriately applied to allogeneic islets, which was delivered to the FDA Cellular, Tissue and Gene Therapies Advisory Committee on 15 April 2021. We provided evidence that BLA requirement and drug related regulations are inadequate in reassuring islet product quality and potency as well as patient safety and clinical outcomes. As leaders in the field of transplantation and endocrinology under the "Islets for US Collaborative" designation, we examined the current regulatory status of islet transplantation in the US and identified several anticipated negative consequences of the BLA approval. In our commentary we also offer an alternative pathway for islet transplantation under the regulatory framework for organ transplantation, which would address deficiencies of in current system.

The Role of Endoscopic Ultrasound-Guided Ki67 in the Management of Non-Functioning Pancreatic Neuroendocrine Tumors.

BACKGROUND/AIMS: The management of small, incidentally discovered nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) has been a matter of debate. Endoscopic ultrasound with fine-needle aspiration (EUS-FNA) is a tool used to identify and risk-stratify PNETs. This study investigates the concordance rate of Ki67 grading between EUS-FNA and surgical pathology specimens in NFPNETs and whether certain NF-PNET characteristics are associated with disease recurrence and disease-related death. METHODS: We retrospectively reviewed the clinical history, imaging, endoscopic findings, and pathology records of 37 cases of NFPNETs that underwent pre-operative EUS-FNA and surgical resection at a single academic medical center. RESULTS: There was 73% concordance between Ki67 obtained from EUS-FNA cytology and surgical pathology specimens; concordance was the highest for low- and high-grade NF-PNETs. High-grade Ki67 NF-PNETs based on cytology (p=0.028) and histology (p=0.028) were associated with disease recurrence and disease-related death. Additionally, tumors with high-grade mitotic rate (p=0.005), tumor size >22.5 mm (p=0.104), and lymphovascular invasion (p=0.103) were more likely to have poor prognosis. CONCLUSION: NF-PNETs with high-grade Ki67 on EUS-FNA have poor prognosis despite surgical resection. NF-PNETs with intermediate-grade Ki67 on EUS-FNA should be strongly considered for surgical resection. NF-PNETs with low-grade Ki67 on EUSFNA can be monitored without surgical intervention, up to tumor size 20 mm.

Noninvasive Young's modulus visualization of fibrosis progression and delineation of pancreatic ductal adenocarcinoma (PDAC) tumors using Harmonic Motion Elastography (HME) in vivo.

Background and aims: Poor specificity and predictive values of current cross-sectional radiological imaging methods in evaluation of pancreatic adenocarcinoma (PDAC) limit the clinical capability to accurately stage the tumor pre-operatively and provide optimal surgical treatment and improve patient outcomes. Methods: In this study, we applied Harmonic Motion Elastography (HME), a quantitative ultrasound-based imaging method to calculate Young's modulus (YM) in PDAC mouse models (n = 30) and human pancreatic resection specimens of PDAC (n=32). We compared the YM to the collagen assessment by Picrosirius red (PSR) stain on corresponding histologic sections. Results: HME is capable of differentiating between different levels of fibrosis in transgenic mice. In mice without pancreatic fibrosis, the measured YM was 4.2 ± 1.3 kPa, in fibrotic murine pancreata, YM was 5.5 ± 2.0 kPa and in murine PDAC tumors, YM was 11.3 ± 1.7 kPa. The corresponding PSR values were 2.0 ± 0.8 %, 9.8 ± 3.4 %, and 13.2 ± 1.2%, respectively. In addition, three regions within each human surgical PDAC specimen were assessed: tumor, which had both the highest Young's modulus (YM > 40 kPa) and collagen density (PSR > 40 %); non-neoplastic adjacent pancreas, which had the lowest Young's modulus (YM < 15 kPa) and collagen density (PSR < 10%) and a transitional peri-lesional region between the tumor and non-neoplastic pancreas with an intermediate value of measured Young's modulus (15 kPa < YM < 40 kPa) and collagen density (15% < PSR < 35 %). Conclusion: In conclusion, a non-invasive, quantitative imaging tool for detecting, staging and delineating PDAC tumor margins based on the change in collagen density was developed.

Harmonic Motion Imaging of Pancreatic Tumor Stiffness Indicates Disease State and Treatment Response.

PURPOSE: Pancreatic ductal adenocarcinoma (PDA) is a common, deadly cancer that is challenging both to diagnose and to manage. Its hallmark is an expansive, desmoplastic stroma characterized by high mechanical stiffness. In this study, we sought to leverage this feature of PDA for two purposes: differential diagnosis and monitoring of response to treatment. EXPERIMENTAL DESIGN: Harmonic motion imaging (HMI) is a functional ultrasound technique that yields a quantitative relative measurement of stiffness suitable for comparisons between individuals and over time. We used HMI to quantify pancreatic stiffness in mouse models of pancreatitis and PDA as well as in a series of freshly resected human pancreatic cancer specimens. RESULTS: In mice, we learned that stiffness increased during progression from preneoplasia to adenocarcinoma and also effectively distinguished PDA from several forms of pancreatitis. In human specimens, the distinction of tumors versus adjacent pancreatitis or normal pancreas tissue was even more stark. Moreover, in both mice and humans, stiffness increased in proportion to tumor size, indicating that tuning of mechanical stiffness is an ongoing process during tumor progression. Finally, using a brca2-mutant mouse model of PDA that is sensitive to cisplatin, we found that tissue stiffness decreases when tumors respond successfully to chemotherapy. Consistent with this observation, we found that tumor tissues from patients who had undergone neoadjuvant therapy were less stiff than those of untreated patients. CONCLUSIONS: These findings support further development of HMI for clinical applications in disease staging and treatment response assessment in PDA.