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.

Protein biomarkers and alternatively methylated cell-free DNA detect early stage pancreatic cancer.

OBJECTIVE: Pancreatic ductal adenocarcinoma (PDAC) is commonly diagnosed at an advanced stage. Liquid biopsy approaches may facilitate detection of early stage PDAC when curative treatments can be employed. DESIGN: To assess circulating marker discrimination in training, testing and validation patient cohorts (total n=426 patients), plasma markers were measured among PDAC cases and patients with chronic pancreatitis, colorectal cancer (CRC), and healthy controls. Using CA19-9 as an anchor marker, measurements were made of two protein markers (TIMP1, LRG1) and cell-free DNA (cfDNA) pancreas-specific methylation at 9 loci encompassing 61 CpG sites. RESULTS: Comparative methylome analysis identified nine loci that were differentially methylated in exocrine pancreas DNA. In the training set (n=124 patients), cfDNA methylation markers distinguished PDAC from healthy and CRC controls. In the testing set of 86 early stage PDAC and 86 matched healthy controls, CA19-9 had an area under the receiver operating characteristic curve (AUC) of 0.88 (95% CI 0.83 to 0.94), which was increased by adding TIMP1 (AUC 0.92; 95% CI 0.88 to 0.96; p=0.06), LRG1 (AUC 0.92; 95% CI 0.88 to 0.96; p=0.02) or exocrine pancreas-specific cfDNA methylation markers at nine loci (AUC 0.92; 95% CI 0.88 to 0.96; p=0.02). In the validation set of 40 early stage PDAC and 40 matched healthy controls, a combined panel including CA19-9, TIMP1 and a 9-loci cfDNA methylation panel had greater discrimination (AUC 0.86, 95% CI 0.77 to 0.95) than CA19-9 alone (AUC 0.82; 95% CI 0.72 to 0.92). CONCLUSION: A combined panel of circulating markers including proteins and methylated cfDNA increased discrimination compared with CA19-9 alone for early stage PDAC.

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.

The Evolving Practice Patterns of Academic Endocrine Surgeons: A Cross-sectional Analysis of the Faculty Practice Solutions Center Database 2014 to 2017.

OBJECTIVE: To examine the evolution of an academic endocrine surgeon's practice over time. SUMMARY BACKGROUND: Amid growing recognition that surgical volume and specialization are linked to better outcomes, endocrine surgery is one of the youngest fields to develop its own formal fellowship training program. However, 3 decades after the emergence of endocrine surgery as a distinct specialty, the medical community and public still have a limited understanding of endocrine surgeons and what they do. METHODS: We performed a cross-sectional analysis of endocrine surgeons identified in the Faculty Practice Solutions Center Database from 2014 to 2017. Trends in annual number of endocrine surgeries performed, number of all surgeries performed, total work relative value units generated, and patient payer mix stratified by years of practice were evaluated. RESULTS: One hundred thirty-nine endocrine surgeons practicing in 103 institutions over 4 years were analyzed. The proportion of endocrine-specific operations increases over time. A typical academic endocrine surgeon meets the high-volume threshold for thyroidectomies early in their career, but does not reach the thresholds for parathyroidectomies or adrenalectomies until after 4 years. Increased productivity as reflected by adjusted work relative value units does increase over the first 15 years of practice, but also decreases as the proportion of endocrine-specific practice increases. The greatest proportion of endocrine surgeons' patients are insured by commercial plans (46%-50%), and payer mix is stable across all levels of practice. CONCLUSIONS: Although endocrine surgeons perform a high-volume of endocrine-specific operations, practice patterns are heterogeneous and suggest that most surgeons have to grow their endocrine-specific practice 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.

Periadrenal Volume is a Better Predictor of Prolonged Operative Time in Laparoscopic Retroperitoneal Adrenalectomy than BMI.

BACKGROUND: Retroperitoneal laparoscopic adrenalectomy is gaining traction as a minimally invasive technique. One of the purported relative contraindications is BMI given the smaller working space. We hypothesize that other anthropometric measurements may be better predictors of operative time. METHODS: An IRB-approved, single-institution, retrospective study of 83 patients who underwent laparoscopic retroperitoneal adrenalectomy evaluated the association of anthropometric measurements taken from cross-sectional imaging and the primary outcome of operative time. Descriptive statistics were performed with Wilcoxon rank-sum test for continuous variables (median; IQR) and Chi-square (n; %) for categorical variables. A linear random effects model was used to model operative time. RESULTS: The majority of the patients were white (40; 48.2%) women (46; 55.4%) with a median age of 54 with interquartile range (IQR) of 43-63 and a median BMI of 27.8 (IQR 21.2-38.6). On univariable analysis, factors that led to longer operative time included right-sided operation (p = 0.04), male gender (p < 0.01), clinical diagnosis (p < 0.01), waist area (p < 0.01), waist/hip ratio (p < 0.01), periadrenal volume (p < 0.01), posterior adiposity index (PAI) (p < 0.01) and BMI (p < 0.01). Only side, order of operation, and periadrenal fat volume (p < 0.01, p = 0.02 and p < 0.01, respectively) remained independent predictors of increased operative time on multivariable analysis. CONCLUSION: This study demonstrates that anthropometric measurements, specifically periadrenal fat volume, and side of operation, are better predictors for increased operative time in laparoscopic retroperitoneal adrenalectomies than BMI. This information can help facilitate appropriate patient selection for this operative approach.

Biochemical Profile Affects IOPTH Kinetics and Cure Rate in Primary Hyperparathyroidism.

BACKGROUND: Recently, normocalcemic (NC) and normohormonal (NH) variants of primary hyperparathyroidism (pHPT) have been described, with distinct biochemical profiles from the typical high serum calcium and parathyroid hormone (PTH) levels. Here, we investigate whether biochemical profile affects cure rate, as well as the kinetics of intraoperative PTH (IOPTH). METHODS: This is a single-center, retrospective study of pHPT patients undergoing parathyroidectomy. Patients were grouped based on preoperative calcium and PTH levels into typical, NC (normal calcium, elevated PTH, no evidence of secondary hyperparathyroidism), and NH (elevated calcium, unsuppressed PTH) biochemical profiles. All patients had IOPTH monitoring and ≥6-month post-op serum studies to confirm surgical cure. Patient variables were analyzed with Kruskal-Wallis test and Chi-square analysis. IOPTH kinetic curves were analyzed using a linear mixed model. RESULTS: From June 2006 to October 2014, 646 patients met inclusion criteria. Biochemical profile was typical in 460 patients (71%), NC in 101 (16%), and NH in 85 (13%). IOPTH levels were higher at all time points in typical patients, p < 0.001. Surgical cure rates were significantly lower for NC patients (90.1%) than for typical (98.5%) or NH patients (97.7%), p < 0.001, although a stricter criteria for cure was used in this group (normal calcium AND normal PTH). In a multivariable linear mixed model, NC patients had a significantly slower rate of IOPTH decline (p < 0.001 at 10 min). CONCLUSIONS: Here, we better characterize the atypical variants of pHPT. Using a stricter definition of cure in the NC variant, these patients have a lower surgical cure rate than typical or NH variants in pHPT. The IOPTH curve is affected by biochemical profile, with both NC and NH patients having lower absolute values and NC patients having a slower decline.

Racial and Socioeconomic Disparities in Access and Utilization of Adrenal Metastasectomy.

BACKGROUND: There is substantial evidence that resecting adrenal metastases can be safely accomplished and extend overall survival in select patients. However, patient access to this operation has not been studied at the population level. The purpose of this study was to determine differences in utilization rates of adrenal metastasectomy (ADMX) across patient populations. METHODS: The Healthcare Utilization Project National Inpatient Sample was used to identify patients who had adrenal metastases (ADM) and who underwent ADMX from 2007 to 2011. Patients were identified by ICD-9-CM diagnosis and procedure codes. Predictor variables included sex, race, median household income, and primary insurance payer. Primary outcomes included receiving an ADMX and same hospitalization mortality. Secondary outcomes included length of stay, infection, cardiac, pulmonary, and renal complications. Univariable and multivariable logistic regression models were used to identify statistical associations. RESULTS: 32,331 ADM and 1070 ADMX patients identified in the database. Despite similar comorbidities, Black patients had 0.30 (95% CI 0.21-0.41) lower odds to receive an ADMX compared to White patients. Medicaid patients had 0.38 (0.28-0.52) less odds and Private Insurance patients 1.18 (1.00-1.39) more odds to receive an ADMX compared to Medicare patients. Women had a 1.39 (1.22-1.58) higher odds ratio of undergoing ADMX compared to men. Of the ADMX cohort, there was no difference in same hospitalization mortality or surgical complications. CONCLUSIONS: Black and Medicaid patients underwent fewer adrenal metastasectomies despite similar comorbidities and postoperative outcomes. This suggests a potential disparity in access to this treatment that disproportionately affects Black and low-income patients, and prompts further study, outreach attempts, as well as, research into improving access.

Experimental microdissection enables functional harmonisation of pancreatic cancer subtypes.

OBJECTIVE: Pancreatic ductal adenocarcinoma (PDA) has among the highest stromal fractions of any cancer and this has complicated attempts at expression-based molecular classification. The goal of this work is to profile purified samples of human PDA epithelium and stroma and examine their respective contributions to gene expression in bulk PDA samples. DESIGN: We used laser capture microdissection (LCM) and RNA sequencing to profile the expression of 60 matched pairs of human PDA malignant epithelium and stroma samples. We then used these data to train a computational model that allowed us to infer tissue composition and generate virtual compartment-specific expression profiles from bulk gene expression cohorts. RESULTS: Our analysis found significant variation in the tissue composition of pancreatic tumours from different public cohorts. Computational removal of stromal gene expression resulted in the reclassification of some tumours, reconciling functional differences between different cohorts. Furthermore, we established a novel classification signature from a total of 110 purified human PDA stroma samples, finding two groups that differ in the extracellular matrix-associated and immune-associated processes. Lastly, a systematic evaluation of cross-compartment subtypes spanning four patient cohorts indicated partial dependence between epithelial and stromal molecular subtypes. CONCLUSION: Our findings add clarity to the nature and number of molecular subtypes in PDA, expand our understanding of global transcriptional programmes in the stroma and harmonise the results of molecular subtyping efforts across independent cohorts.

Vitamin D Does Not Affect Intraoperative Parathyroid Hormone Kinetics: A Mixed Linear Model Analysis.

BACKGROUND: Intraoperative parathyroid hormone (ioPTH) monitoring is used to confirm completeness of resection in patients undergoing parathyroidectomy for primary hyperparathyroidism (pHPT). Though there is an inverse relationship between vitamin D and parathyroid hormone (PTH), previous studies have suggested that 25-hydroxyvitamin D (25OHD) level does not affect the likelihood of meeting the Miami criterion. Here, we further investigate whether preoperative 25OHD level affects ioPTH kinetics. METHODS: This is a retrospective case-control study of patients undergoing parathyroidectomy for pHPT at a tertiary referral center. Patients were categorized based on preoperative 25OHD level as vitamin D deficient (≤ 20 ng/mL), insufficient (21-30 ng/mL), or sufficient (>30 ng/mL). Differences in baseline characteristics were analyzed with Kruskal-Wallis H test or chi-square analysis. ioPTH kinetic curves were analyzed using a log-transformed mixed linear model with subject-level random effects. Significance was set at P < 0.05. RESULTS: Among 630 patients who met inclusion criteria, there was a significant difference in ioPTH between groups at baseline (P < 0.001), but not at any other time point. As a continuous variable, as well as a categorical variable, in a mixed linear model, vitamin D had no significant effect on ioPTH kinetics. CONCLUSIONS: Despite a difference in preoperative and baseline PTH levels, preoperative 25OHD had no significant effect on ioPTH kinetics. Therefore, ioPTH assays can be used and interpreted uniformly, regardless of patients' vitamin D status.

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.