Combined Antitumor Effect of the Serine Protease Urokinase Inhibitor Upamostat and the Sphingosine Kinase 2 Inhibitor Opaganib on Cholangiocarcinoma Patient-Derived Xenografts.

Upamostat is an orally available small-molecule serine protease inhibitor that is a highly potent inhibitor of trypsin 1, trypsin 2, trypsin 3 (PRSS1/2/3), and the urokinase-type plasminogen activator (uPA). These enzymes are expressed in many cancers, especially during tissue remodeling and subsequent tumor cell invasion. Opaganib (ABC294640), a novel, orally available small molecule is a selective inhibitor of the phosphorylation of sphingosine to sphingosine-1-phosphate (S-1-P) by sphingosine kinase 2 (SPHK2). Both sphingosine kinase 1 (SPHK1) and SPHK2 are known to regulate the proliferation-inducing compound S-1-P. However, SPHK2 is more critical in cancer pathogenesis. The goal of this project was to investigate the potential antitumor effects of upamostat and opaganib, individually and in combination, on cholangiocarcinoma (CCA) xenografts in nude mice. PAX165, a patient-derived xenograft (PDX) from a surgically resected CCA, expresses substantial levels of SPHK2, PRSS1, PRSS2, and PRSS3. Four groups of 18 mice each were treated with upamostat, opaganib, both, or vehicle. Mouse weights and PAX165 tumor volumes were measured. Tumor volumes in the upamostat, opaganib, and upamostat plus opaganib groups were significantly decreased compared to the control group.

In vivo label-free optical signatures of chemotherapy response in human pancreatic ductal adenocarcinoma patient-derived xenografts.

Pancreatic cancer is a devastating disease often detected at later stages, necessitating swift and effective chemotherapy treatment. However, chemoresistance is common and its mechanisms are poorly understood. Here, label-free multi-modal nonlinear optical microscopy was applied to study microstructural and functional features of pancreatic tumors in vivo to monitor inter- and intra-tumor heterogeneity and treatment response. Patient-derived xenografts with human pancreatic ductal adenocarcinoma were implanted into mice and characterized over five weeks of intraperitoneal chemotherapy (FIRINOX or Gem/NabP) with known responsiveness/resistance. Resistant and responsive tumors exhibited a similar initial metabolic response, but by week 5 the resistant tumor deviated significantly from the responsive tumor, indicating that a representative response may take up to five weeks to appear. This biphasic metabolic response in a chemoresistant tumor reveals the possibility of intra-tumor spatiotemporal heterogeneity of drug responsiveness. These results, though limited by small sample size, suggest the possibility for further work characterizing chemoresistance mechanisms using nonlinear optical microscopy.

Therapeutic Efficacy of Temsirolimus in a Patient-derived Model of Metastatic Fibrolamellar Hepatocellular Carcinoma.

BACKGROUND/AIM: Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare tumor presenting in younger patients without chronic liver disease. Up to 80-100% develop recurrent disease, necessitating additional surgery or systemic treatment. Systemic options and pre-clinical treatment studies are lacking. We previously described patient-derived xenograft (PDX) development, allowing for pre-clinical studies. Herein, we develop FLHCC PDX models and utilize these to define tumor characteristics and determine the efficacy of systemic agents. MATERIALS AND METHODS: Primary and lymph node metastatic tumor tissues were obtained at the time of FLHCC resection in two patients. Tumor lysates were screened for protein upregulation. Cell lines were generated from metastatic and primary tumor tissue. The viability of the cell lines was assessed after treatment with temsirolimus, gemcitabine/oxaliplatin, and FOLFIRINOX. Two PDX models were developed from metastatic tissue. For in vivo studies, tumor-bearing mice were treated with temsirolimus, FOLFIRINOX, and Gemcitabine/oxaliplatin. RESULTS: PDX models were successfully generated from metastatic FLHCC, which closely recapitulated the original tumor. Upregulation of mTOR was seen in metastatic tissue compared to primary tumors. Cell lines from metastatic tissue demonstrated significant sensitivity to temsirolimus. In vivo testing of PDX models demonstrated a significant response to single-agent temsirolimus with minimal toxicity. CONCLUSION: Herein, we demonstrate the feasibility of developing PDX models that closely recapitulate FLHCC. Upregulation of mTOR was seen in metastatic tissue compared to primary tissue. The efficacy of mTOR inhibition with temsirolimus treatment suggests that the upregulation of the mTOR pathway may be a significant mechanism for growth in metastatic lesions and a potential target for therapeutics.

Mixed Acinar Neuroendocrine Carcinoma of the Pancreas: Comparative Population-Based Epidemiology of a Rare and Fatal Malignancy in The United States.

Mixed acinar neuroendocrine carcinoma of the pancreas (MANEC-P) is an extremely rare malignancy with a poor prognosis. However, epidemiological estimates of MANEC-P remain unknown. This study aimed to estimate and compare the incidence, prevalence, and cancer-specific survival (CSS) of MANEC-P in the United States (US). Patients with MANEC-P were identified through the Surveillance, Epidemiology, and End Results (SEER) and National Program of Cancer Registries databases between 2000-2017. The primary outcomes included age-adjusted incidence rate, limited-duration prevalence, and CSS. A total of 630 patients were identified for the incidence analysis and 149 for the prevalence and CSS analyses. The MANEC-P incidence rate was 0.011 per 100,000 individuals, which was the lowest among pancreatic cancer histologic subtypes. The incidence rate was significantly higher in men and Black races and peaked at 75-79 years of age. The incidence rate was the lowest in the midwestern region (0.009) and the highest in the northeastern US (0.013). The 17-year prevalence was 0.00005%, indicating that 189 patients were alive in the United States at the beginning of 2018. The median CSS of MANEC-P was estimated to be 41 (23, 69) months. In conclusion, MANEC-P is very rare, and its incidence rate has been steady in the US over the last two decades. MANEC-P has a poor prognosis and is the 5th leading cause of pancreatic cancer-related death in the US.

Conditional Survival Following Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Surface Malignancies: An Analysis from the US HIPEC Collaborative.

INTRODUCTION: The long-term prognosis of patients who undergo cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal surface malignancies (PSM) varies considerably on the basis of histological and operative factors. While overall survival (OS) estimates are used to inform adjuvant therapy and surveillance strategies, conditional survival may provide more clinically relevant estimates of prognosis by accounting for disease-free time elapsed. PATIENTS AND METHODS: All patients from 12 academic institutions who underwent CRS ± HIPEC for PSM from 2000 to 2017 were retrospectively analyzed. OS and disease-free survival (DFS) rates were calculated using the Kaplan-Meier method while conditional overall (COS) and conditional disease-free survival (CDFS) rates were calculated at 1, 2, or 3 years from surgery for different tumor histologies. RESULTS: Overall, 1610 patients underwent CRS ± HIPEC. Among patients with benign appendiceal mucinous tumors (N = 460), 5-year OS and COS at 3 years were 92.1% and 96.3% (Δ4.2%), respectively. For patients with well-differentiated appendiceal cancers (N = 400), 5-year OS and COS at 3 years were 76.3% and 88.3% (Δ12.0%), respectively. For patients with high-grade appendiceal cancers (N = 258), 5-year OS and COS at 3 years were 43.8% and 75.4% (Δ31.6%), respectively. For patients with colorectal cancers (N = 362), 5-year OS and COS at 3 years were 31.8% and 67.3% (Δ35.5%), respectively. For patients with peritoneal mesothelioma (N = 130), 5-year OS and COS at 3 years were 67.6% and 89.7% (Δ22.1%), respectively. Similar trends were observed for DFS/CDFS. CONCLUSION: The conditional survival of patients undergoing CRS ± HIPEC for PSM is associated with tumor histology. COS and CDFS provide a more accurate, dynamic estimate of survival than OS and DFS, especially for patients with more aggressive histologies.

FDG-PET Predicts Neoadjuvant Therapy Response and Survival in Borderline Resectable/Locally Advanced Pancreatic Adenocarcinoma.

BACKGROUND: Neoadjuvant therapy (NAT) is used in borderline resectable/locally advanced (BR/LA) pancreatic ductal adenocarcinoma (PDAC). Anatomic imaging (CT/MRI) poorly predicts response, and biochemical (CA 19-9) markers are not useful (nonsecretors/nonelevated) in many patients. Pathologic response highly predicts survival post-NAT, but is only known postoperatively. Because metabolic imaging (FDG-PET) reveals primary tumor viability, this study aimed to evaluate our experience with preoperative FDG-PET in patients with BR/LA PDAC in predicting NAT response and survival. METHODS: We reviewed all patients with resected BR/LA PDAC who underwent NAT with FDG-PET within 60 days of resection. Pre- and post-NAT metabolic (FDG-PET) and biochemical (CA 19-9) responses were dichotomized in addition to pathologic responses. We compared post-NAT metabolic and biochemical responses as preoperative predictors of pathologic responses and recurrence-free survival (RFS) and overall survival (OS). RESULTS: We identified 202 eligible patients. Post-NAT, 58% of patients had optimization of CA 19-9 levels. Major metabolic and pathologic responses were present in 51% and 38% of patients, respectively. Median RFS and OS times were 21 and 48.7 months, respectively. Metabolic response was superior to biochemical response in predicting pathologic response (area under the curve, 0.86 vs 0.75; P<.001). Metabolic response was the only univariate preoperative predictor of OS (odds ratio, 0.25; 95% CI, 0.13-0.40), and was highly correlated (P=.001) with pathologic response as opposed to biochemical response alone. After multivariate adjustment, metabolic response was the single largest independent preoperative predictor (P<.001) for pathologic response (odds ratio, 43.2; 95% CI, 16.9-153.2), RFS (hazard ratio, 0.37; 95% CI, 0.2-0.6), and OS (hazard ratio, 0.21; 95% CI, 0.1-0.4). CONCLUSIONS: Among patients with post-NAT resected BR/LA PDAC, FDG-PET highly predicts pathologic response and survival, superior to biochemical responses alone. Given the poor ability of anatomic imaging or biochemical markers to assess NAT responses in these patients, FDG-PET is a preoperative metric of NAT efficacy, thereby allowing potential therapeutic alterations and surgical treatment decisions. We suggest that FDG-PET should be an adjunct and recommended modality during the NAT phase of care for these patients.

Synergistic combination of cytotoxic chemotherapy and cyclin-dependent kinase 4/6 inhibitors in biliary tract cancers.

BACKGROUND AND AIMS: Biliary tract cancers (BTCs) are uncommon, but highly lethal, gastrointestinal malignancies. Gemcitabine/cisplatin is a standard-of-care systemic therapy, but has a modest impact on survival and harbors toxicities, including myelosuppression, nephropathy, neuropathy, and ototoxicity. Whereas BTCs are characterized by aberrations activating the cyclinD1/cyclin-dependent kinase (CDK)4/6/CDK inhibitor 2a/retinoblastoma pathway, clinical use of CDK4/6 inhibitors as monotherapy is limited by lack of validated biomarkers, diffident preclinical efficacy, and development of acquired drug resistance. Emerging studies have explored therapeutic strategies to enhance the antitumor efficacy of CDK4/6 inhibitors by the combination with chemotherapy regimens, but their mechanism of action remains elusive. APPROACH AND RESULTS: Here, we report in vitro and in vivo synergy in BTC models, showing enhanced efficacy, reduced toxicity, and better survival with a combination comprising gemcitabine/cisplatin and CDK4/6 inhibitors. Furthermore, we demonstrated that abemaciclib monotherapy had only modest efficacy attributable to autophagy-induced resistance. Notably, triplet therapy was able to potentiate efficacy through elimination of the autophagic flux. Correspondingly, abemaciclib potentiated ribonucleotide reductase catalytic subunit M1 reduction, resulting in sensitization to gemcitabine. CONCLUSIONS: As such, these data provide robust preclinical mechanistic evidence of synergy between gemcitabine/cisplatin and CDK4/6 inhibitors and delineate a path forward for translation of these findings to preliminary clinical studies in advanced BTC patients.

Identification of Novel Therapeutic Targets for Fibrolamellar Carcinoma Using Patient-Derived Xenografts and Direct-from-Patient Screening.

To repurpose therapeutics for fibrolamellar carcinoma (FLC), we developed and validated patient-derived xenografts (PDX) from surgical resections. Most agents used clinically and inhibitors of oncogenes overexpressed in FLC showed little efficacy on PDX. A high-throughput functional drug screen found primary and metastatic FLC were vulnerable to clinically available inhibitors of TOPO1 and HDAC and to napabucasin. Napabucasin's efficacy was mediated through reactive oxygen species and inhibition of translation initiation, and specific inhibition of eIF4A was effective. The sensitivity of each PDX line inversely correlated with expression of the antiapoptotic protein Bcl-xL, and inhibition of Bcl-xL synergized with other drugs. Screening directly on cells dissociated from patient resections validated these results. This demonstrates that a direct functional screen on patient tumors provides therapeutically informative data within a clinically useful time frame. Identifying these novel therapeutic targets and combination therapies is an urgent need, as effective therapeutics for FLC are currently unavailable. SIGNIFICANCE: Therapeutics informed by genomics have not yielded effective therapies for FLC. A functional screen identified TOPO1, HDAC inhibitors, and napabucasin as efficacious and synergistic with inhibition of Bcl-xL. Validation on cells dissociated directly from patient tumors demonstrates the ability for functional precision medicine in a solid tumor.This article is highlighted in the In This Issue feature, p. 2355.

Molecular Peritoneal Staging for Pancreatic Ductal Adenocarcinoma Using Mutant KRAS Droplet-Digital Polymerase Chain Reaction: Results of a Prospective Clinical Trial.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with predilection for peritoneal dissemination. Accurate peritoneal staging is imperative for treatment recommendations, as one-third of patients develop peritoneal recurrence after resection. Because >90% of PDAC tumors harbor mutant KRAS (mKRAS), we sought to determine feasibility of mKRAS DNA detection in peritoneal lavage (PL) fluid using droplet-digital polymerase chain reaction (ddPCR) via a prospective trial. STUDY DESIGN: Patients with nonmetastatic PDAC undergoing staging laparoscopy with PL were included. PL fluid was sent for cytologic examination, CA19-9/CEA levels, and mKRAS ddPCR assay. Clinically positive laparoscopy was defined as gross metastases or positive cytology. PL mKRAS status was compared with gross findings, cytology, and CA19-9/CEA levels. RESULTS: There were 136 patients enrolled; 70 of 136 (51%) patients received neoadjuvant therapy before PL, and 32 of 136 (24%) patients had clinically positive laparoscopy. Cytology was positive in 17 of 136 (13%) patients, and 22 of 136 (16%) patients had gross metastases. Of patients with gross metastases, only 8 of 22 (36%) had positive cytology; 97 of 136 (71%) patients had mKRAS in PL. PL mKRAS was present in 27 of 32 (84%) clinically positive laparoscopies, with higher mean copy number in clinically positive patients (643 vs 10, p = 0.02). Peritoneal mKRAS was positive in an additional 70 clinically negative patients. CONCLUSIONS: This prospective study establishes the feasibility of PL mKRAS detection. Clinically positive disease was identified in 1 in 4 staging laparoscopies. Although PL mKRAS was highly associated with clinically positive findings, many clinically negative laparoscopies had detectable PL mKRAS, suggesting that standard staging may be inadequate. Longer follow-up will elucidate utility of this promising molecular assay.

The impact of HIPEC vs. EPIC for the treatment of mucinous appendiceal carcinoma: a study from the US HIPEC collaborative.

INTRODUCTION: Mucinous appendiceal carcinoma is a rare malignancy that commonly spreads to the peritoneum leading to peritoneal metastases. Complete cytoreduction with perioperative intraperitoneal chemotherapy (PIC) is the mainstay of treatment, administered as either hyperthermic intra peritoneal chemotherapy (HIPEC) or early post-operative intraperitoneal chemotherapy (EPIC). Our goal was to assess the perioperative and long term survival outcomes associated with these two PIC methods. MATERIALS AND METHODS: Patients with mucinous appendiceal carcinoma were identified in the US HIPEC Collaborative database from 12 academic institutions. Patient demographics, clinical characteristics, and survival outcomes were compared among patients who underwent HIPEC vs. EPIC with inverse probability weighting (IPW) used for adjustment. RESULTS: Among 921 patients with mucinous appendiceal carcinoma, 9% underwent EPIC while 91% underwent HIPEC. There was no difference in Grade III-V complications between the two groups (18.5% for HIPEC vs. 15.0% for EPIC, p=.43) though patients who underwent HIPEC had higher rates of readmissions (21.2% vs. 8.8%, p<.01). Additionally, PIC method was not an independent predictor for overall survival (OS) or recurrence-free survival (RFS) after adjustment on multivariable analysis. CONCLUSIONS: Among patients with mucinous appendiceal carcinoma, both EPIC and HIPEC appear to be associated with similar perioperative and long-term outcomes.

Genomic and Epigenomic Landscaping Defines New Therapeutic Targets for Adenosquamous Carcinoma of the Pancreas.

Adenosquamous cancer of the pancreas (ASCP) is a subtype of pancreatic cancer that has a worse prognosis and greater metastatic potential than the more common pancreatic ductal adenocarcinoma (PDAC) subtype. To distinguish the genomic landscape of ASCP and identify actionable targets for this lethal cancer, we applied DNA content flow cytometry to a series of 15 tumor samples including five patient-derived xenografts (PDX). We interrogated purified sorted tumor fractions from these samples with whole-genome copy-number variant (CNV), whole-exome sequencing, and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) analyses. These identified a variety of somatic genomic lesions targeting chromatin regulators in ASCP genomes that were superimposed on well-characterized genomic lesions including mutations in TP53 (87%) and KRAS (73%), amplification of MYC (47%), and homozygous deletion of CDKN2A (40%) that are common in PDACs. Furthermore, a comparison of ATAC-seq profiles of three ASCP and three PDAC genomes using flow-sorted PDX models identified genes with accessible chromatin unique to the ASCP genomes, including the lysine methyltransferase SMYD2 and the pancreatic cancer stem cell regulator RORC in all three ASCPs, and a FGFR1-ERLIN2 fusion associated with focal CNVs in both genes in a single ASCP. Finally, we demonstrate significant activity of a pan FGFR inhibitor against organoids derived from the FGFR1-ERLIN2 fusion-positive ASCP PDX model. Our results suggest that the genomic and epigenomic landscape of ASCP provide new strategies for targeting this aggressive subtype of pancreatic cancer. SIGNIFICANCE: These data provide a unique description of the ASCP genomic and epigenomic landscape and identify candidate therapeutic targets for this dismal cancer.

Comparison of open and closed hyperthermic intraperitoneal chemotherapy: Results from the United States hyperthermic intraperitoneal chemotherapy collaborative.

BACKGROUND: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal carcinomatosis can be performed in two ways: Open or closed abdominal technique. AIM: To evaluate the impact of HIPEC method on post-operative and long-term survival outcomes. METHODS: Patients undergoing CRS with HIPEC from 2000-2017 were identified in the United States HIPEC collaborative database. Post-operative, recurrence, and overall survival outcomes were compared between those who received open vs closed HIPEC. RESULTS: Of the 1812 patients undergoing curative-intent CRS and HIPEC, 372 (21%) patients underwent open HIPEC and 1440 (79%) underwent closed HIPEC. There was no difference in re-operation or severe complications between the two groups. Closed HIPEC had higher rates of 90-d readmission while open HIPEC had a higher rate of 90-d mortalities. On multi-variable analysis, closed HIPEC technique was not a significant predictor for overall survival (hazards ratio: 0.75, 95% confidence interval: 0.51-1.10, P = 0.14) or recurrence-free survival (hazards ratio: 1.39, 95% confidence interval: 1.00-1.93, P = 0.05) in the entire cohort. These findings remained consistent in the appendiceal and the colorectal subgroups. CONCLUSION: In this multi-institutional analysis, the HIPEC method was not independently associated with relevant post-operative or long-term outcomes. HIPEC technique may be left to the discretion of the operating surgeon.

Institutional variation in recovery after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: An opportunity for enhanced recovery pathways.

BACKGROUND: Variations in care have been demonstrated both within and among institutions in many clinical settings. By standardizing perioperative practices, Enhanced Recovery After Surgery (ERAS) pathways reduce variation in perioperative care. We sought to characterize the variation in cytoreductive surgery (CRS)/heated intraperitoneal chemotherapy (HIPEC) perioperative practices among experienced US medical centers. METHODS: Data from the US HIPEC Collaborative represents a retrospective multi-institutional cohort study of CRS and CRS/HIPEC procedures performed from 12 major academic institutions. Patient characteristics and perioperative practices were reported and compared. Institutional variation was analyzed using hierarchical mixed-effects linear (continuous outcomes) or logistic (binary outcomes) regression models. RESULTS: A total of 2372 operations were included. CRS/HIPEC was performed most commonly for appendiceal histologies (64.2%). The rate of complications (overall 56.3%, range: 31.8-70.9) and readmissions (overall 20.6%, range: 8.9-33.3) varied by institution (P < .001). Institution-level variation in perioperative practice patterns existed among measured ERAS pathway process/outcomes (P < .001). The percentages of variation with each process/outcome measure attributable solely to institutional practices ranged from 0.6% to 66.6%. CONCLUSIONS: Significant variation exists in the perioperative care of patients undergoing CRS/HIPEC at major US academic institutions. These findings provide a strong rationale for the investigation of best practices in CRS/HIPEC patients.

Evaluation of NUC-1031: a first-in-class ProTide in biliary tract cancer.

PURPOSE: NUC1031 is a first-in-class ProTide, that is a gemcitabine pro-drug designed to overcome putative mechanisms of resistance, including decreased expression of hENT/hCNT transporters, absence of activating enzymes such as deoxycytidine kinase (dCK) and presence of degrading enzymes such as cytidine deaminase (CDA). We undertook comprehensive pre-clinical evaluation of NUC1031 in biliary tract cancer (BTC) models, given that gemcitabine/cisplatin is a standard first-line therapy in advanced BTC. METHODS: Here, we compared the in vitro activity of NUC1031 in comparison to gemcitabine, validate putative mechanism(s) of action, assessed potential biomarkers of sensitivity or resistance, and performed combination studies with cisplatin. We also evaluated the in vivo efficacy of NUC1031 and gemcitabine using a CDA-high cholangiocarcinoma patient-derived xenograft (PDX) model. RESULTS: In a panel of BTC cell lines (N = 10), NUC1031 had less potency than gemcitabine in multiple cellular assays. NUC1031 did not demonstrate evidence of greater synergy over gemcitabine in combination with cisplatin. Surprisingly, efficacy of both gemcitabine and NUC1031 was not found to be correlated with hENT/hCTN, dCK or CDA transcript levels. Gemcitabine and NUC1031 showed equivalent efficacy in a CDA-high PDX model in vivo contradicting the primary rationale of NUC1031 design. CONCLUSION: NUC1031 did not exhibit evidence of superior activity over gemcitabine, as a single-agent, or in combination with cisplatin, in either our in vivo or in vitro BTC models. Given that the largest Phase 3 study (ClinicalTrials.gov: NCT0314666) to date in BTC is underway (N = 828) comparing NUC1031/cisplatin to gemcitabine/cisplatin, our results suggest that a more conservative clinical evaluation path would be more appropriate.

Impact of Neoadjuvant Chemotherapy on the Outcomes of Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Colorectal Peritoneal Metastases: A Multi-Institutional Retrospective Review.

Cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC) is associated with improved survival for patients with colorectal peritoneal metastases (CR-PM). However, the role of neoadjuvant chemotherapy (NAC) prior to CRS-HIPEC is poorly understood. A retrospective review of adult patients with CR-PM who underwent CRS+/-HIPEC from 2000-2017 was performed. Among 298 patients who underwent CRS+/-HIPEC, 196 (65.8%) received NAC while 102 (34.2%) underwent surgery first (SF). Patients who received NAC had lower peritoneal cancer index score (12.1 + 7.9 vs. 14.3 + 8.5, p = 0.034). There was no significant difference in grade III/IV complications (22.4% vs. 16.7%, p = 0.650), readmission (32.3% vs. 23.5%, p = 0.114), or 30-day mortality (1.5% vs. 2.9%, p = 0.411) between groups. NAC patients experienced longer overall survival (OS) (median 32.7 vs. 22.0 months, p = 0.044) but similar recurrence-free survival (RFS) (median 13.8 vs. 13.0 months, p = 0.456). After controlling for confounding factors, NAC was not independently associated with improved OS (OR 0.80) or RFS (OR 1.04). Among patients who underwent CRS+/-HIPEC for CR-PM, the use of NAC was associated with improved OS that did not persist on multivariable analysis. However, NAC prior to CRS+/-HIPEC was a safe and feasible strategy for CR-PM, which may aid in the appropriate selection of patients for aggressive cytoreductive surgery.

Biliary tract cancer patient-derived xenografts: Surgeon impact on individualized medicine.

BACKGROUND & AIMS: Biliary tract tumors are uncommon but highly aggressive malignancies with poor survival outcomes. Due to their low incidence, research into effective therapeutics has been limited. Novel research platforms for pre-clinical studies are desperately needed. We sought to develop a patient-derived biliary tract cancer xenograft catalog. METHODS: With appropriate consent and approval, surplus malignant tissues were obtained from surgical resection or radiographic biopsy and implanted into immunocompromised mice. Mice were monitored for xenograft growth. Established xenografts were verified by a hepatobiliary pathologist. Xenograft characteristics were correlated with original patient/tumor characteristics and oncologic outcomes. A subset of xenografts were then genomically characterized using Mate Pair sequencing (MPseq). RESULTS: Between October 2013 and January 2018, 87 patients with histologically confirmed biliary tract carcinomas were enrolled. Of the 87 patients, 47 validated PDX models were successfully generated. The majority of the PDX models were created from surgical resection specimens (n = 44, 94%), which were more likely to successfully engraft when compared to radiologic biopsies (p = 0.03). Histologic recapitulation of original patient tumor morphology was observed in all xenografts. Successful engraftment was an independent predictor for worse recurrence-free survival. MPseq showed genetically diverse tumors with frequent alterations of CDKN2A, SMAD4, NRG1, TP53. Sequencing also identified worse survival in patients with tumors containing tetraploid genomes. CONCLUSIONS: This is the largest series of biliary tract cancer xenografts reported to date. Histologic and genomic analysis of patient-derived xenografts demonstrates accurate recapitulation of original tumor morphology with direct correlations to patient outcomes. Successful development of biliary cancer tumografts is feasible and may be used to direct subsequent therapy in high recurrence risk patients. LAY SUMMARY: Patient biliary tract tumors grown in immunocompromised mice are an invaluable resource in the treatment of biliary tract cancers. They can be used to guide individualized cancer treatment in high-risk patients.

What is the Optimal Preoperative Imaging Modality for Assessing Peritoneal Cancer Index? An Analysis From the United States HIPEC Collaborative.

BACKGROUND: Radiographic prediction of peritoneal carcinomatosis index (PCI) can improve patient selection for cytoreductive surgery. We aimed to determine the correlation of computed tomography (CT)-predicted PCI (CT-PCI) and magnetic resonance imaging (MRI)-predicted PCI (MRI-PCI) with intraoperative-PCI, and if a preoperative-PCI cutoff is associated with incomplete cytoreduction. PATIENTS AND METHODS: Patients from the US HIPEC Collaborative (2000-2017) with appendiceal, colorectal, or peritoneal mesothelioma (PM) histology who underwent cytoreductive surgery were included. Pearson correlation coefficients were used to determine correlation between preoperative and intraoperative-PCI values. Fisher r-to-z transformation was used to compare correlations. RESULTS: A total of 488 patients were included. Of these, 34% had noninvasive appendiceal, 30% invasive appendiceal, 28% colorectal, and 8% PM histology. CT-PCI was correlated with intraoperative-PCI for patients with noninvasive and invasive appendiceal and colorectal histologies (r = 0.689, 0.554, and 0.571; all P < .001), but not PM (r = 0.188; P = .295). MRI-PCI was correlated with intraoperative-PCI for all histologies (non-invasive appendiceal: r = 0.591; P = .002; invasive appendiceal: r = 0.848; P < .001; colorectal: r = 0.729; P < .001; PM: r = 0.890; P = .007). Comparing CT and MRI, correlations were similar in noninvasive appendiceal and colorectal histologies; MRI was better for invasive appendiceal and PM (P = .005 and P = .021, respectively). Twenty-eight (6%) patients underwent an incomplete cytoreduction (cytoreduction score, 2-3). PCI greater than 15 was associated with cytoreduction score of 2 to 3 for both CT and MRI (CT-PCI: odds ratio, 3.0; P = .033; MRI-PCI: odds ratio, 7.6; P = .071). CONCLUSIONS: In this multi-institutional cohort, CT and MRI-PCI correlate well with intraoperative-PCI. MRI appears to be superior for invasive appendiceal and peritoneal mesothelioma. External validation in a larger population is needed.

Advancements and challenges in treating advanced gastric cancer in the West.

Gastric cancer is a leading cause of cancer incidence and death worldwide. Patients with advanced gastric cancer benefit from a multi-modality treatment regimen. Sound oncologic resection with negative margins and complete lymphadenectomy plays a crucial role in long-term survival for patients with resectable disease. The utilization of minimally invasive techniques for gastric cancer has been slowly increasing and is proving to be both technically and oncologically safe. Perioperative chemotherapy is the current standard of care for advanced gastric cancer. A variety of chemotherapy regimens have been used with the combination of docetaxel, oxaliplatin, 5-fluorouracil, and leucovorin being the current recommendation given its superior ability to induce a complete pathologic response and prolong survival. The use of radiation has been more controversial with its optimal place in the treatment sequence being unclear. There are current ongoing studies assessing the impact of radiation as an adjunct or in place of chemotherapy. Targeted treatments (e.g., trastuzumab for human epidermal growth factor receptor 2 positive tumors and pembrolizumab for programmed death-ligand 1 positive tumors) are showing promise and are part of a continued emphasis on individualized care. Intraperitoneal chemotherapy may also play a role in preventing peritoneal recurrences for patients with high risk lesions. The treatment of patients with advanced gastric cancer in the West continues to advance and improve with a better understanding of optimal treatment sequences and the utilization of personalized treatment regimens.