Tumour-selective activity of RAS-GTP inhibition in pancreatic cancer.

Broad-spectrum RAS inhibition has the potential to benefit roughly a quarter of human patients with cancer whose tumours are driven by RAS mutations1,2. RMC-7977 is a highly selective inhibitor of the active GTP-bound forms of KRAS, HRAS and NRAS, with affinity for both mutant and wild-type variants3. More than 90% of cases of human pancreatic ductal adenocarcinoma (PDAC) are driven by activating mutations in KRAS4. Here we assessed the therapeutic potential of RMC-7977 in a comprehensive range of PDAC models. We observed broad and pronounced anti-tumour activity across models following direct RAS inhibition at exposures that were well-tolerated in vivo. Pharmacological analyses revealed divergent responses to RMC-7977 in tumour versus normal tissues. Treated tumours exhibited waves of apoptosis along with sustained proliferative arrest, whereas normal tissues underwent only transient decreases in proliferation, with no evidence of apoptosis. In the autochthonous KPC mouse model, RMC-7977 treatment resulted in a profound extension of survival followed by on-treatment relapse. Analysis of relapsed tumours identified Myc copy number gain as a prevalent candidate resistance mechanism, which could be overcome by combinatorial TEAD inhibition in vitro. Together, these data establish a strong preclinical rationale for the use of broad-spectrum RAS-GTP inhibition in the setting of PDAC and identify a promising candidate combination therapeutic regimen to overcome monotherapy resistance.

Methionine oxidation activates pyruvate kinase M2 to promote pancreatic cancer metastasis.

Cancer mortality is primarily a consequence of its metastatic spread. Here, we report that methionine sulfoxide reductase A (MSRA), which can reduce oxidized methionine residues, acts as a suppressor of pancreatic ductal adenocarcinoma (PDA) metastasis. MSRA expression is decreased in the metastatic tumors of PDA patients, whereas MSRA loss in primary PDA cells promotes migration and invasion. Chemoproteomic profiling of pancreatic organoids revealed that MSRA loss results in the selective oxidation of a methionine residue (M239) in pyruvate kinase M2 (PKM2). Moreover, M239 oxidation sustains PKM2 in an active tetrameric state to promote respiration, migration, and metastasis, whereas pharmacological activation of PKM2 increases cell migration and metastasis in vivo. These results demonstrate that methionine residues can act as reversible redox switches governing distinct signaling outcomes and that the MSRA-PKM2 axis serves as a regulatory nexus between redox biology and cancer metabolism to control tumor metastasis.

Inadequacy of the eighth edition of the American Joint Committee on Cancer pancreatic cancer staging system for invasive carcinoma associated with premalignant lesions in the pancreas: an analysis using the National Cancer Database.

BACKGROUND: Invasive carcinomas arising from premalignant lesions are currently staged by the same criteria as conventional pancreatic ductal adenocarcinoma. METHODS: Clinicopathologic information and survival data were extracted through a thorough search of histology codes from National Cancer Database (2006-2016). A total of 723 patients with invasive intraductal papillary mucinous neoplasm and mucinous cystic neoplasm were analyzed. RESULTS: The median age was 67 years, and 351 patients (48.5%) were male. There were 212 (29.3%), 232 (32.1%), 272 (37.6%), and 7 (1.0%) patients with T1, T2, T3, and T4 classification. Extrapancreatic extension (EPE) was present in 284 (39.3%). Age (HR = 1.504, 95% CI 1.196-1.891), R1 or R2 resection (HR = 1.585, 95% CI 1.175-2.140), and EPE (HR = 1.598, 95% CI 1.209-2.113) were independent prognostic factors for overall survival. Size criteria did not significantly affect survival. The median survival was 115.9 months for patients without EPE, compared to 34.2 months for those with EPE. EPE discriminated survival better than tumor size. DISCUSSION: The T classification of the eighth edition AJCC staging system is not adequate for invasive carcinomas associated with premalignant lesions of the pancreas. They merit a separate, dedicated staging system that uses appropriate prognostic factors.

High rate of stone-related complications after stapling the cystic duct during laparoscopic cholecystectomy-an underrecognized risk.

BACKGROUND: Laparoscopic staplers (LS) have been suggested as a safe alternative to metal clips in laparoscopic cholecystectomy when the cystic duct is too inflamed or wide for complete clip occlusion. We aimed to evaluate the perioperative outcomes of patients whose cystic ducts were controlled by LS and evaluate the risk factors for complications. METHODS: Patients who underwent laparoscopic cholecystectomy with LS used to control the cystic duct from 2005 to 2019 were retrospectively identified from an institutional database. Patients were excluded for open cholecystectomy, partial cholecystectomy, or cancer. Potential risk factors for complications were assessed using logistic regression analysis. RESULTS: Among 262 patients, 191 (72.9%) were stapled for size and 71 (27.1%) for inflammation. In total, 33 (16.3%) patients had Clavien-Dindo grade ≥ 3 complications, with no significant difference when surgeons chose to staple for duct size versus inflammation (p = 0.416). Seven patients had bile duct injury. A large proportion had Clavien-Dindo grade ≥ 3 postoperative complications specifically related to bile duct stones [n = 29 (11.07%)]. Intraoperative cholangiogram was protective against postoperative complications [odds ratio (OR) = 0.18 (p = 0.022)]. CONCLUSION: Whether these high complication rates reflect a technical issue with stapling, more challenging anatomy, or worse disease, findings question whether the use of LS during laparoscopic cholecystectomy is truly a safe alternative to the already accepted methods of cystic duct ligation and transection. Based on these findings, an intraoperative cholangiogram should be performed when considering a linear stapler during laparoscopic cholecystectomy to: (1) ensure the biliary tree is free of stones; (2) prevent inadvertent transection of the infundibulum rather than the cystic duct; and, (3) allow opportunity for safe alternative strategies when an IOC is not able to confirm anatomy. Otherwise, surgeons employing LS devices should be aware that patients are at higher risk for complications.

Contemporary practice and perception of autologous blood salvage in hepato-pancreatico-biliary operations: an international survey.

BACKGROUND: This study aimed to assess contemporary knowledge, attitudes and behaviors around transfusion of intraoperative salvaged blood (sRBCt) during hepato-pancreatico-biliary (HPB) operations. Findings are meant to inform the design of future studies that address provider concerns to change behaviors and improve patient outcomes. METHODS: A survey was designed and assessed for relevance, readability and content, and distributed to an international audience of surgeons performing HPB operations. RESULTS: The 237 respondents were predominantly distributed across North America (37.55%), Europe (27.43%) and Asia (19.83%). Roughly one-half (52.74%) of respondents had used sRBCt in HPB surgery before. Transplantation surgeons were more likely than HPB surgeons to have previously used sRBCt [odds ratio = 5.18 (95% CI 1.89-14.20)]. More respondents believed sRBCt was safe for non-cancer versus cancer operations (68.57% vs. 24.17%, p < 0.0001). Less than half (45.71%) of respondents believed that sRBCt was safe in clean-contaminated fields. Most did not utilize preoperative strategies to avoid donor transfusion. CONCLUSION: Practices related to sRBCt in HPB operations vary widely and there is no consensus on its use. Concerns seem primarily related to cancer-specific and infectious outcomes. While further studies are pursued, surgeons may increase their utilization of preoperative strategies to boost hemoglobin levels for at risk patients.

Lead-Time Trajectory of CA19-9 as an Anchor Marker for Pancreatic Cancer Early Detection.

BACKGROUND & AIMS: There is substantial interest in liquid biopsy approaches for cancer early detection among subjects at risk, using multi-marker panels. CA19-9 is an established circulating biomarker for pancreatic cancer; however, its relevance for pancreatic cancer early detection or for monitoring subjects at risk has not been established. METHODS: CA19-9 levels were assessed in blinded sera from 175 subjects collected up to 5 years before diagnosis of pancreatic cancer and from 875 matched controls from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. For comparison of performance, CA19-9 was assayed in blinded independent sets of samples collected at diagnosis from 129 subjects with resectable pancreatic cancer and 275 controls (100 healthy subjects; 50 with chronic pancreatitis; and 125 with noncancerous pancreatic cysts). The complementary value of 2 additional protein markers, TIMP1 and LRG1, was determined. RESULTS: In the PLCO cohort, levels of CA19-9 increased exponentially starting at 2 years before diagnosis with sensitivities reaching 60% at 99% specificity within 0 to 6 months before diagnosis for all cases and 50% at 99% specificity for cases diagnosed with early-stage disease. Performance was comparable for distinguishing newly diagnosed cases with resectable pancreatic cancer from healthy controls (64% sensitivity at 99% specificity). Comparison of resectable pancreatic cancer cases to subjects with chronic pancreatitis yielded 46% sensitivity at 99% specificity and for subjects with noncancerous cysts, 30% sensitivity at 99% specificity. For prediagnostic cases below cutoff value for CA19-9, the combination with LRG1 and TIMP1 yielded an increment of 13.2% in sensitivity at 99% specificity (P = .031) in identifying cases diagnosed within 1 year of blood collection. CONCLUSION: CA19-9 can serve as an anchor marker for pancreatic cancer early detection applications.

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.

Use and Misuse of Opioids After Endocrine Surgery Operations.

OBJECTIVE: To examine the rate of new and persistent opioid use after endocrine surgery operations. SUMMARY OF BACKGROUND DATA: A global epidemic of opioid misuse and abuse has been evolving over the past 2 decades with opioid use among surgical patients being a particularly difficult problem. Minimal data exists regarding opioid misuse after endocrine surgical operations. METHODS: A retrospective cohort study using the MarketScan identified adult patients who underwent thyroidectomy, parathyroidectomy, neck dissections for thyroid malignancy, and adrenalectomy from 2008 to 2017. Persistent opioid use was defined as receipt of ≥1 opioid prescription 90-180 days postop with no intervening procedures or anesthesia. Multivariable models were used to examine associations between clinical characteristics and any use and new persistent use of opioids. RESULTS: A total of 259,115 patients were identified; 54.6% of opioid naïve patients received a perioperative opioid prescription. Fulfillment of this prescription was associated with malignant disease, greater extent of surgery, younger age, residence outside of the Northeast, and history of depression or substance abuse. The rate of new persistent opioid use was 7.4%. A lateral neck dissection conferred the highest risk for persistent opioid use (P < 0.01). Persistent opioid use was also associated with older age, Medicaid coverage, residency outside of the Northeast, increased medical co-morbidities, a history of depression, anxiety, substance use disorder, and chronic pain (all P < 0.01). Importantly, the risk for persistent opioid use increased with higher doses of total amount of opioids prescribed. CONCLUSIONS: The rate of new, persistent opioid use after endocrine surgery operations is substantial but may be mitigated by decreasing the number of postoperative 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.

Two-Stage Cytoreductive Surgery and Intraperitoneal Chemotherapy for Diffuse Malignant Peritoneal Mesothelioma: Predictors of Overall Survival in an Intention-to-Treat Series.

PURPOSE: Cytoreductive surgery with intraoperative hyperthermic intraperitoneal chemotherapy is standard of care for diffuse malignant peritoneal mesothelioma (DMPM), but there is variability among institutions in the administration of adjuvant chemotherapy. Characterization of the largest series of DMPM patients treated at a single institution and identification of the demographic, disease, and treatment factors associated with overall survival were sought. PATIENTS AND METHODS: All DMPM patients who underwent initial cytoreductive surgery with the intention to undergo intraperitoneal chemotherapy and a second-look operation from 1995 to 2016 at our institution were retrospectively reviewed. The primary endpoint was overall survival. RESULTS: A total of 204 DMPM patients underwent initial cytoreduction. Median overall survival was 32 months from initial cytoreduction. Independent baseline prognostic factors of improved overall survival were female sex, age < 60 years, and epithelioid histology. Independent treatment factors associated with improved overall survival were attempted resection at initial operation, residual disease < 0.5 cm at the end of the initial operation, and dwell intraperitoneal chemotherapy. CONCLUSIONS: Cytoreductive surgery with intraoperative and dwell intraperitoneal chemotherapy is a feasible approach for DMPM. Expanded access to these therapies may offer benefit to a larger population of patients. Demographic and operative parameters associated with overall survival in this large cohort are consistent with previous reports. In the context of this treatment protocol, dwell intraperitoneal chemotherapy is associated with longer overall survival.

50 Patients with Malignant Mesothelioma of Both the Pleura and Peritoneum: A Single-Institution Experience.

BACKGROUND: The most common sites of malignant mesothelioma are the pleura and peritoneum, but little is known about the incidence, prognosis, or treatment of patients with disease in both cavities. Previous series suggest that multimodality treatment improves overall survival for pleural or peritoneal disease, but studies typically exclude patients with disease in both cavities. Despite limitations, this investigation is the only study to broadly examine outcomes for patients with malignant mesothelioma in both the pleural and peritoneal cavities. METHODS: This study retrospectively examined 50 patients with both pleural and peritoneal mesothelioma treated with the intent to prolong survival. The primary end point was overall survival from the initial operative intervention. RESULTS: The median overall survival was 33.9 months from the initial intervention. Female gender and intraperitoneal dwell chemotherapy were independent predictors of overall survival. Within 1 year after the initial diagnosis, second-cavity disease was diagnosed in 52% of the patients. The median time to the second-cavity diagnosis for those with a diagnosis 1 year after the initial diagnosis was 30 months. CONCLUSIONS: Well-selected patients with both pleural and peritoneal mesothelioma have a survival benefit over palliative treatment that is comparable with that seen in single-cavity disease. The presence of disease in both cavities is not a contraindication to multimodality treatment aimed at prolonging survival, whether the disease is diagnosed synchronously or metachronously. Patients with an initial diagnosis of single cavity disease are at the highest risk for identification of second-cavity disease within the first year after diagnosis.

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.

Risk Factors and Mitigation Strategies for Pancreatic Fistula After Distal Pancreatectomy: Analysis of 2026 Resections From the International, Multi-institutional Distal Pancreatectomy Study Group.

OBJECTIVE: To identify a clinical fistula risk score following distal pancreatectomy. BACKGROUND: Clinically relevant pancreatic fistula (CR-POPF) following distal pancreatectomy (DP) is a dominant contributor to procedural morbidity, yet risk factors attributable to CR-POPF and effective practices to reduce its occurrence remain elusive. METHODS: This multinational, retrospective study of 2026 DPs involved 52 surgeons at 10 institutions (2001-2016). CR-POPFs were defined by 2016 International Study Group criteria, and risk models generated using stepwise logistic regression analysis were evaluated by c-statistic. Mitigation strategies were assessed by regression modeling while controlling for identified risk factors and treating institution. RESULTS: CR-POPF occurred following 306 (15.1%) DPs. Risk factors independently associated with CR-POPF included: age (<60 yrs: OR 1.42, 95% CI 1.05-1.82), obesity (OR 1.54, 95% CI 1.19-2.12), hypoalbuminenia (OR 1.63, 95% CI 1.06-2.51), the absence of epidural anesthesia (OR 1.59, 95% CI 1.17-2.16), neuroendocrine or nonmalignant pathology (OR 1.56, 95% CI 1.18-2.06), concomitant splenectomy (OR 1.99, 95% CI 1.25-3.17), and vascular resection (OR 2.29, 95% CI 1.25-3.17). After adjusting for inherent risk between cases by multivariable regression, the following were not independently associated with CR-POPF: method of transection, suture ligation of the pancreatic duct, staple size, the use of staple line reinforcement, tissue patches, biologic sealants, or prophylactic octreotide. Intraoperative drainage was associated with a greater fistula rate (OR 2.09, 95% CI 1.51-3.78) but reduced fistula severity (P < 0.001). CONCLUSIONS: From this large analysis of pancreatic fistula following DP, CR-POPF occurrence cannot be reliably predicted. Opportunities for developing a risk score model are limited for performing risk-adjusted analyses of mitigation strategies and surgeon performance.

Recurrence of Optimally Treated Malignant Peritoneal Mesothelioma with Cytoreduction and Heated Intraperitoneal Chemotherapy.

BACKGROUND: The prognosis for patients with diffuse malignant peritoneal mesothelioma has dramatically improved with cytoreductive surgery and intraperitoneal chemotherapy. Little is known about disease recurrence after treatment. We analyzed the time to and predictors of recurrence in a large cohort of optimally treated patients. METHODS: We examined 113 patients completing a two-stage cytoreduction and intraperitoneal chemotherapy protocol. All patients achieved optimal surgical resection with completeness of cytoreduction (CC) score ≤ 1 and were divided into two groups based on absence (Group A) or presence (Group B) of gross disease at the outset of the second operation. Predictors of disease recurrence and recurrence-free survival (RFS) were determined using Cox proportional hazard regression modeling, and estimates were obtained by using the Kaplan-Meier method. RESULTS: Forty-six percent of patients had no gross evidence of disease at the second operation; the remaining 54% were cytoreduced to CC ≤ 1 (Group B). Forty-two percent of patients developed disease recurrence with a median recurrence-free survival of 38.5 months for the cohort; 79% of these received a form of iterative treatment. There was no statistically significant difference in recurrence-free survival between Group A (median RFS: 44.6 months) and B (median RFS: 35.5 months) (log-rank test, p = 0.06). Additionally, the only variable significantly associated with RFS was male gender (hazard ratio [HR] 1.98, 95% confidence interval [CI] 1.16-3.38). CONCLUSIONS: Absence of gross disease at the second operation was not statistically protective against recurrence compared with presence of quantifiable residual disease (Group B) that was effectively cytoreduced. Long-term disease surveillance is recommended, because recurrence continues years after treatment. Where a question of recurrence arises on surveillance, males may benefit from a higher degree of suspicion.

Can diffusion-weighted imaging serve as a biomarker of fibrosis in pancreatic adenocarcinoma?

PURPOSE: To assess the relationship between diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM)-derived quantitative parameters (apparent diffusion coefficient [ADC], perfusion fraction [f], Dslow , diffusion coefficient [D], and Dfast , pseudodiffusion coefficient [D*]) and histopathology in pancreatic adenocarcinoma (PAC). MATERIALS AND METHODS: Subjects with suspected surgically resectable PAC were prospectively enrolled in this Health Insurance Portability and Accountability Act (HIPAA)-compliant, Institutional Review Board-approved study. Imaging was performed at 1.5T with a respiratory-triggered echo planar DWI sequence using 10 b values. Two readers drew regions of interest (ROIs) over the tumor and adjacent nontumoral tissue. Monoexponential and biexponential fits were used to derive ADC2b , ADCall , f, D, and D*, which were compared to quantitative histopathology of fibrosis, mean vascular density, and cellularity. Two biexponential IVIM models were investigated and compared: 1) nonlinear least-square fitting based on the Levenberg-Marquardt algorithm, and 2) linear fit using a fixed D* (20 mm2 /s). Statistical analysis included Student's t-test, Pearson correlation (P < 0.05 was considered significant), intraclass correlation, and coefficients of variance. RESULTS: Twenty subjects with PAC were included in the final cohort. Negative correlation between D and fibrosis (Reader 2: r = -0.57 P = 0.01; pooled P = -0.46, P = 0.04) was observed with a trend toward positive correlation between f and fibrosis (r = 0.44, P = 0.05). ADC2b was significantly lower in PAC with dense fibrosis than with loose fibrosis ADC2b (P = 0.03). Inter- and intrareader agreement was excellent for ADC, D, and f. CONCLUSION: In PAC, D negatively correlates with fibrosis, with a trend toward positive correlation with f suggesting both perfusion and diffusion effects contribute to stromal desmoplasia. ADC2b is significantly lower in tumors with dense fibrosis and may serve as a biomarker of fibrosis architecture. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:393-402.

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.

PET-avid hepatocellular adenomas: incidental findings associated with HNF1-α mutated lesions.

BACKGROUND: Hepatocellular adenoma (HCA) is the second most common benign liver neoplasm and occurs predominantly in women in their reproductive years. Positron emission tomography (PET) using [18F] fluorodeoxyglucose (FDG) is commonly used in cancer staging, surveillance and evaluation of treatment response. PET-avid HCA are rare and can be falsely interpreted as malignancies. METHODS: A retrospective review of four institutions' database was performed to identify the PET-avid HCAs with clinico-pathological correlation. RESULTS: Nine patients with histological proven PET-avid HCA was identified. Eight out of 9 patients were female with a median age at diagnosis of 44 years. All patients' tumors with available histological subtyping (8/8) were HNF1-α mutated and had no inflammatory changes; 6 out the 9 lesions had prominent (>50%) steatotic changes. CONCLUSION: Hepatocellular adenomas, specifically the HNF1-α subtype, can cause false-positive PET findings when seeking to identify malignancy. Concomitantly, PET-CT may have the potential to identify the HCA histopathologic variant with the lowest malignant and hemorrhagic potential.