Allosteric regulation and crystallographic fragment screening of SARS-CoV-2 NSP15 endoribonuclease.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). The NSP15 endoribonuclease enzyme, known as NendoU, is highly conserved and plays a critical role in the ability of the virus to evade the immune system. NendoU is a promising target for the development of new antiviral drugs. However, the complexity of the enzyme's structure and kinetics, along with the broad range of recognition sequences and lack of structural complexes, hampers the development of inhibitors. Here, we performed enzymatic characterization of NendoU in its monomeric and hexameric form, showing that hexamers are allosteric enzymes with a positive cooperative index, and with no influence of manganese on enzymatic activity. Through combining cryo-electron microscopy at different pHs, X-ray crystallography and biochemical and structural analysis, we showed that NendoU can shift between open and closed forms, which probably correspond to active and inactive states, respectively. We also explored the possibility of NendoU assembling into larger supramolecular structures and proposed a mechanism for allosteric regulation. In addition, we conducted a large fragment screening campaign against NendoU and identified several new allosteric sites that could be targeted for the development of new inhibitors. Overall, our findings provide insights into the complex structure and function of NendoU and offer new opportunities for the development of inhibitors.

Structural basis of nirmatrelvir and ensitrelvir activity against naturally occurring polymorphisms of the SARS-CoV-2 main protease.

SARS-CoV-2 is the causative agent of COVID-19. The main viral protease (Mpro) is an attractive target for antivirals. The clinically approved drug nirmatrelvir and the clinical candidate ensitrelvir have so far showed great potential for treatment of viral infection. However, the broad use of antivirals is often associated with resistance generation. Herein, we enzymatically characterized 14 naturally occurring Mpro polymorphisms that are close to the binding site of these antivirals. Nirmatrelvir retained its potency against most polymorphisms tested, while mutants G143S and Q189K were associated with diminished inhibition constants. For ensitrelvir, diminished inhibition constants were observed for polymorphisms M49I, G143S, and R188S, but not for Q189K, suggesting a distinct resistance profile between inhibitors. In addition, the crystal structures of selected polymorphisms revealed interactions that were critical for loss of potency. In conclusion, our data will assist the monitoring of potential resistant strains, support the design of combined therapy, as well as assist the development of the next generation of Mpro inhibitors.

Dense tumor-infiltrating lymphocytes (TILs) in liver metastasis from colorectal cancer are related to improved overall survival.

BACKGROUND AND OBJECTIVES: Tumor-infiltrating lymphocytes (TILs) represent a host-tumor interaction, frequently signifying an augmented immunological response. Nonetheless, implications with survival outcomes in patients with colorectal carcinoma liver metastasis (CRLM) warrant rigorous validation. The objective was to demonstrate the association between TILs and survival in patients with CRLM. METHOD: In a retrospective evaluation conducted in a single institution, we assessed all patients who underwent hepatectomy due to CRLM between 2014 and 2018. Comprehensive medical documentation reviews were executed. TILs were assessed by a liver pathologist, blinded to the clinical information, in all surgical slides. RESULTS: This retrospective cohort included 112 patients. Median overall survival (OS) was 58 months and disease-free survival (DFS) was 12 months for the entire cohort. Comparison between groups showed a median OS of 81 months in the dense TILs group and 40 months in the weak/absent group (p = 0.001), and DFS was 14 months versus 9 months (p = 0.041). Multivariable analysis showed that TILs were an independent predictor of OS (HR 1.95; p = 0.031). CONCLUSIONS: Dense TILs are a pivotal prognostic indicator, correlating with enhanced OS. Including TILs information in histopathological evaluations should refine the clinical decision-making process for this group of patients.

The protein disulfide isomerase inhibitor 3-methyltoxoflavin inhibits Chikungunya virus.

Chikungunya virus (CHIKV) is the etiological agent of chikungunya fever, a (re)emerging arbovirus infection, that causes severe and often persistent arthritis, as well as representing a serious health concern worldwide for which no antivirals are currently available. Despite efforts over the last decade to identify and optimize new inhibitors or to reposition existing drugs, no compound has progressed to clinical trials for CHIKV and current prophylaxis is based on vector control, which has shown limited success in containing the virus. Our efforts to rectify this situation were initiated by screening 36 compounds using a replicon system and ultimately identified the natural product derivative 3-methyltoxoflavin with activity against CHIKV using a cell-based assay (EC50 200 nM, SI = 17 in Huh-7 cells). We have additionally screened 3-methyltoxoflavin against a panel of 17 viruses and showed that it only additionally demonstrated inhibition of the yellow fever virus (EC50 370 nM, SI = 3.2 in Huh-7 cells). We have also showed that 3-methyltoxoflavin has excellent in vitro human and mouse microsomal metabolic stability, good solubility and high Caco-2 permeability and it is not likely to be a P-glycoprotein substrate. In summary, we demonstrate that 3-methyltoxoflavin has activity against CHIKV, good in vitro absorption, distribution, metabolism and excretion (ADME) properties as well as good calculated physicochemical properties and may represent a valuable starting point for future optimization to develop inhibitors for this and other related viruses.

Symptomatic Recurrence and Survival Outcomes After Curative Treatment of Gastric Cancer: Does Intensive Follow-up Evaluation Improve Survival?

BACKGROUND: Intensive surveillance after treatment of gastric cancer patients with curative intent may lead to an earlier diagnosis of disease recurrence, but its impact on survival is uncertain. This study aimed to evaluate whether early diagnosis of disease recurrence among asymptomatic patients was associated with long-term survival. METHODS: This retrospective study analyzed patients with stages 1 to 3C gastric adenocarcinoma treated between 1999 and 2018. All recurrence events were classified as symptomatic or asymptomatic (detected by follow-up tests), and their clinicopathologic characteristics, patterns of recurrence, and survival were analyzed. RESULTS: The cohort consisted of 669 patients treated with a total gastrectomy in 48.6% and a D2-lymphadenectomy in 88.8% of the cases. Most of the tumors were pT3-4 (46.5%), with 45.5% involving lymph node metastases and 42.3% manifesting a diffuse histology. During a median follow-up period of 80.1 months (95% confidence interval [CI], 75.3-84.8 months), 166 patients had recurrences (24.8%), 65.7% of which were symptomatic. The peritoneum was the main site of recurrence (37.2%), and peritoneal recurrence was associated with worse overall survival (OS) (hazard ratio, 1.69; 95%CI, 1.2-2.37). The median disease-free, post-recurrence survival, and OS periods in the asymptomatic and symptomatic groups were respectively 13.4 versus 17.2 months (p = 0.04), 11.9 versus 4.7 months (p < 0.001), and 29.9 versus 26.4 months (p = 0.21). When OS was analyzed among the patients with non-peritoneal recurrence, no difference was observed between the two groups (31.3 vs 31.1 months; p = 0.46). CONCLUSION: Early diagnosis of asymptomatic disease recurrence did not affect the OS of the gastric cancer patients treated with curative intent. The use of intensive surveillance strategies in this scenario still requires further evidence.

Surgery or active surveillance for pNETs < 2 cm: Preliminary results from a single center Brazilian cohort.

BACKGROUND AND OBJECTIVES: Incidence of pancreatic neuroendocrine tumors (pNETS) seems to be rising over the years, with many cases incidentally diagnosed. Surgery and active surveillance are current treatment modalities for small pNETS. We review our institutional series and compare outcomes for small asymptomatic and nonfunctioning tumors. METHODS: This retrospective cohort study included patients with 2 cm or less and well differentiated pNETS at a single Brazilian Cancer Center. From 2002 to 2020, patients received active surveillance or surgery as a treatment strategy. Short and long-term results were compared. RESULTS: Sixty-four patients were included, 41 in surgical strategy and 23 in the active surveillance approach. Baseline group characteristics were comparable. More patients on active surveillance underwent abdominal magnetic resonance imaging (MRI) and had tumors located in the pancreatic head (41% vs. 17%, p = 0.038). Minimally invasive procedure was chosen in 80.1% of the surgical patients. No patient died after surgery. Median follow-up period was 38.6 and 46.4 months for active surveillance and surgery cohorts, respectively. No difference in disease progression rate was observed. CONCLUSION: Both approaches seem to be safe for small pNETs. Long-term outcome and quality of life should be considered when discussing such options with patients.

Patterns of disease relapse and posttreatment follow-up of patients with resected pancreatic adenocarcinoma: A single-center analysis.

BACKGROUND AND OBJECTIVES: To describe the patterns of disease relapse and follow-up of patients with resected pancreatic adenocarcinoma. Additionally, we looked at patients' characteristics at relapse and survival. METHODS: We included patients with potentially resectable pancreatic adenocarcinoma diagnosed from 2008 to 2018 who were submitted to resection with clear macroscopic margins and started posttreatment surveillance. RESULTS: The study population consists of 73 patients. The median interval between imaging studies was 3.2 months during the first 2 years of follow-up and 5.1 months thereafter. Forty-eight patients (65.8%) experienced disease relapse. The most frequent single site of relapse was locoregional (N = 21; 43.8%). At relapse, 31 patients (64.6%) were symptomatic and forty-two patients (87.6%) had Eastern Cooperative Oncology Group performance status 0 or 1. Most patients were able to undergo additional anticancer therapy (N = 41; 85.4%). Patients with asymptomatic relapses experienced longer median postrelapse survival (25.4 vs. 11.3 months; p = 0.015). CONCLUSIONS: A follow-up protocol that included imaging studies every 3 months in the first 2 years and every 6 months thereafter is able to diagnose disease relapse when patients have adequate performance status and are still able to undergo additional anticancer treatment.

PD-L1 expression in gastric and gastroesophageal junction cancer patients treated with perioperative chemotherapy.

BACKGROUND AND OBJECTIVES: The incidence, predictive, and prognostic impact of programmed cell death (PD-L1) expression in gastric (GC) and gastroesophageal junction tumors (GEJC) treated with perioperative chemotherapy is poorly understood. We aimed to assess PD-L1 expression by immunohistochemistry (IHC) in both pre and posttreatment specimens evaluating its impact on pathological response and survival outcomes. METHODS: Retrospective cohort of patients with GC and GEJ tumors treated in a single western cancer center between 2007 and 2017. PD-L1 expression was assessed by IHC before and after neoadjuvant chemotherapy, in surgical samples, and reported as combined positive score (CPS). CPS > 1% was tested for its association with pathological response and overall survival (OS). RESULTS: We were able to assess PD-L1 expression in at least one tissue sample from 155 subjects. PD-L1 positivity rate was 20%. In 74 paired samples, a 21% discordance between PD-L1 expression in biopsy sample and surgical specimen was observed. With a median follow-up period of 60.3 months, 5-years disease-free survival was 60.5% with a median OS not reached. PD-L1 expression was neither associated with pathological response or survival outcomes. CONCLUSIONS: PD-L1 expression in the setting of locally advanced GC tumors was relatively low and can vary considering the tissue sample analyzed. This expression had no association with survival or pathological response in this population.

Development of Machine Learning Models and the Discovery of a New Antiviral Compound against Yellow Fever Virus.

Yellow fever (YF) is an acute viral hemorrhagic disease transmitted by infected mosquitoes. Large epidemics of YF occur when the virus is introduced into heavily populated areas with high mosquito density and low vaccination coverage. The lack of a specific small molecule drug treatment against YF as well as for homologous infections, such as zika and dengue, highlights the importance of these flaviviruses as a public health concern. With the advancement in computer hardware and bioactivity data availability, new tools based on machine learning methods have been introduced into drug discovery, as a means to utilize the growing high throughput screening (HTS) data generated to reduce costs and increase the speed of drug development. The use of predictive machine learning models using previously published data from HTS campaigns or data available in public databases, can enable the selection of compounds with desirable bioactivity and absorption, distribution, metabolism, and excretion profiles. In this study, we have collated cell-based assay data for yellow fever virus from the literature and public databases. The data were used to build predictive models with several machine learning methods that could prioritize compounds for in vitro testing. Five molecules were prioritized and tested in vitro from which we have identified a new pyrazolesulfonamide derivative with EC50 3.2 µM and CC50 24 µM, which represents a new scaffold suitable for hit-to-lead optimization that can expand the available drug discovery candidates for YF.

Machine Learning Models Identify Inhibitors of SARS-CoV-2.

With the rapidly evolving SARS-CoV-2 variants of concern, there is an urgent need for the discovery of further treatments for the coronavirus disease (COVID-19). Drug repurposing is one of the most rapid strategies for addressing this need, and numerous compounds have already been selected for in vitro testing by several groups. These have led to a growing database of molecules with in vitro activity against the virus. Machine learning models can assist drug discovery through prediction of the best compounds based on previously published data. Herein, we have implemented several machine learning methods to develop predictive models from recent SARS-CoV-2 in vitro inhibition data and used them to prioritize additional FDA-approved compounds for in vitro testing selected from our in-house compound library. From the compounds predicted with a Bayesian machine learning model, lumefantrine, an antimalarial was selected for testing and showed limited antiviral activity in cell-based assays while demonstrating binding (Kd 259 nM) to the spike protein using microscale thermophoresis. Several other compounds which we prioritized have since been tested by others and were also found to be active in vitro. This combined machine learning and in vitro testing approach can be expanded to virtually screen available molecules with predicted activity against SARS-CoV-2 reference WIV04 strain and circulating variants of concern. In the process of this work, we have created multiple iterations of machine learning models that can be used as a prioritization tool for SARS-CoV-2 antiviral drug discovery programs. The very latest model for SARS-CoV-2 with over 500 compounds is now freely available at www.assaycentral.org.

Non-Toxic Dimeric Peptides Derived from the Bothropstoxin-I Are Potent SARS-CoV-2 and Papain-like Protease Inhibitors.

The COVID-19 outbreak has rapidly spread on a global scale, affecting the economy and public health systems throughout the world. In recent years, peptide-based therapeutics have been widely studied and developed to treat infectious diseases, including viral infections. Herein, the antiviral effects of the lysine linked dimer des-Cys11, Lys12,Lys13-(pBthTX-I)2K ((pBthTX-I)2K)) and derivatives against SARS-CoV-2 are reported. The lead peptide (pBthTX-I)2K and derivatives showed attractive inhibitory activities against SARS-CoV-2 (EC50 = 28-65 µM) and mostly low cytotoxic effect (CC50 > 100 µM). To shed light on the mechanism of action underlying the peptides' antiviral activity, the Main Protease (Mpro) and Papain-Like protease (PLpro) inhibitory activities of the peptides were assessed. The synthetic peptides showed PLpro inhibition potencies (IC50s = 1.0-3.5 µM) and binding affinities (Kd = 0.9-7 µM) at the low micromolar range but poor inhibitory activity against Mpro (IC50 > 10 µM). The modeled binding mode of a representative peptide of the series indicated that the compound blocked the entry of the PLpro substrate toward the protease catalytic cleft. Our findings indicated that non-toxic dimeric peptides derived from the Bothropstoxin-I have attractive cellular and enzymatic inhibitory activities, thereby suggesting that they are promising prototypes for the discovery and development of new drugs against SARS-CoV-2 infection.

Predictors of long-term survival in patients with hepatic resection of colorectal metastases: Analysis of a Brazilian Cancer Center Cohort.

BACKGROUND: Hepatic metastases are a major cause of death in patients with colorectal cancer. A comprehensive assessment of the prognostic factors associated with long-term survival could improve patient selection for surgical approaches and decrease morbidity and futile locoregional treatments. METHODS: We performed a retrospective analysis of patients who underwent hepatectomy for colorectal liver metastases at a single center from 2000 to 2012. RESULTS: To identify factors associated with 5- and 10-year overall (OS) and disease-free survival (DFS), we analyzed 280 patients and 150 patients in the 5- and 10-year cohorts, respectively. Only seven relapses occurred after 5 years of follow-up, and no relapses occurred after 10 years. Multivariable analysis indicated that bilobar disease and extra-hepatic disease before hepatectomy were independent 5- and 10-year predictors of OS, and major postoperative complications predicted OS in the 5-year survival cohort only. Our analysis indicated that prognostic factors associated with DFS included some confounders and was therefore inconclusive. CONCLUSIONS: Taken together, our results suggest that the predictors of 5- and 10-year OS rates of colorectal cancer patients with hepatic metastases are similar, differing only by postoperative complications that influenced exclusively 5-year survival. Since no relapse occurred 10 years after hepatic resection, oncological remission is likely.

Does hipec improve outcomes in gastric cancer patients treated with perioperative chemotherapy and radical surgery? A propensity-score matched analysis.

BACKGROUND: Hyperthermic intraperitoneal chemotherapy (HIPEC) has been associated with improved survival when compared with surgery alone for non-metastatic gastric cancer patients in randomized trials and meta-analyses. However, little evidence is available regarding the use of HIPEC in nonmetastatic patients who are treated with perioperative chemotherapy and radical surgery. The aim of this study was to investigate the putative survival benefit of HIPEC in the subgroup of gastric cancer patients treated with perioperative chemotherapy and surgery. PATIENTS AND METHODS: This was a retrospective cohort study that included gastroesophageal junction and gastric cancer patients who were treated with perioperative chemotherapy and curative resection in a single cancer center in the period between 2006 and 2017. In this time period, younger patients with diffuse-type tumors and serosa invasion or positive lymph node disease were often offered an adjuvant HIPEC protocol. This study compared the survival outcomes of these patients to the ones of those who received only perioperative chemotherapy and resection. A 2:1 propensity-score matched analysis for the two groups was also performed, and variables used were postchemotherapy T (ypT) and N (ypN) stages, histology and tumor site. RESULTS: The study population comprised 269 subjects, 241 treated with chemotherapy and surgery and 28 who also received HIPEC. The mean age was 59 years old (standard deviation: 12.2) and 60% of all individuals were male. A total gastrectomy was performed in 137 patients and a distal resection in 132, with a D2-lymphadenectomy in 97.4% of the sample. Overall 60-day morbidity and mortality rates were 35.3% and 3.3%, respectively. In the HIPEC group, patients were younger, and more frequently had American Society of Anesthesiologists (ASA) 1 to 2 classification, tumors located in the gastric body, had diffuse histology, and ypN+ disease. Overall survival (OS; 5 years) results in the HIPEC and no HIPEC group were 59.5% vs 68.7% (P = .453), and disease-free survival (DFS) ones were 49.5% and 65.8% (P = .060), respectively. In the multivariable Cox regression model, ypT and ypN were independent overall and DFS predictors; also, ASA 3 to 4 classification and diffuse histology were associated with worse OS. In the matched analysis, HIPEC did not improve either overall (53.5% vs 59.5%; P = .517) or DFS (50.0% vs 49.5%; P = .993). CONCLUSION: Treatment with HIPEC in patients who received perioperative chemotherapy and a D2-resection did not improve survival outcomes. Both ypT and ypN stages remained as the most important survival predictors in this cohort.

Short-term outcomes after vascular resection for pancreatic tumors: Lessons learned from 72 cases from a single Brazilian Cancer Center.

INTRODUCTION: Pancreatic malignant tumors are resectable at diagnosis in only 15% to 20% of cases and invasion of vascular structures is commonly present. Therefore, extended resections are needed for adequate local control and negative margins. However, morbidity and mortality associated with these enlarged resections are limiting factors. The aim of this study was to correlate demographic and technical aspects that influenced early and late outcomes. MATERIALS AND METHODS: Between October 2007 and May 2019, 523 pancreatic surgeries were performed, of which 72 required vascular resections. Clinical and histopathological data, surgical techniques, and perioperative parameters were analyzed in a prospectively collected database. RESULTS: Of the 72 cases of vascular resection, 31 were male and 41 females with a mean age of 60.9 years (34-81). The most commonly affected vascular structure was the portal vein (in 40.3%). Free margins were obtained in 77.8% of cases. Postoperative mortality rate at 60 days was 13.9%. American Society of Anesthesiologists (ASA) and age were the most important predictors of major complications. CONCLUSION: Extended resections with vascular involvement in pancreatic surgeries are feasible and safe; furthermore, patient selection plays are key. ASA and age were the most important factors in the decision-making process for extended resections.

Impact of ypT, ypN, and Adjuvant Therapy on Survival in Gastric Cancer Patients Treated with Perioperative Chemotherapy and Radical Surgery.

BACKGROUND: Perioperative chemotherapy and surgery is the standard of care in advanced gastroesophageal cancer patients, but its impact among those treated with radical surgery still needs further assessment. We present the results of this multimodality treatment approach in a gastric cancer patients cohort treated with D2 lymphadenectomy. We aimed to identify prognostic factors associated with improved survival. PATIENTS AND METHODS: This retrospective cohort study enrolled patients treated with perioperative chemotherapy and resection in a single cancer center in Brazil between 2006 and 2016. Subjects presenting tumors of the gastric stump, esophageal tumors, or treated with intraperitoneal chemotherapy were excluded. Intention-to-treat survival analysis was performed for all subjects who started neoadjuvant chemotherapy, and prognostic factors were determined among those who had R0 resection. RESULTS: This study included 239 patients, of whom 198 had R0 resection. The mean age was 59.9 years, and most had clinical stage IIB or III disease (88%). Among the 239 patients who started neoadjuvant chemotherapy, 207 (86.6%) completed all neoadjuvant treatment cycles, and surgical resection was performed in 225 subjects (94.1%). Overall 60-day morbidity and mortality rates were 35.6% and 4.4%, respectively. For the entire cohort, median survival was 78 months and the 5-year survival rate was 55.3%. Factors associated with worse survival were ypT3-4 stage, ypN + stage, extended resection, and no adjuvant chemotherapy. CONCLUSIONS: Perioperative chemotherapy resulted in very good outcomes for patients treated with radical surgery, and downstaging after chemotherapy was shown to be a major determinant of prognosis.

Predicting overall and major postoperative morbidity in gastric cancer patients.

BACKGROUND: Postoperative complications after gastric cancer resection vary in different series and they might have a significant impact in long-term outcomes. Our aim was to build a prediction rule on gastric cancer patients' overall and major morbidity risks. METHODS: This retrospective study included 1223 patients from a single center who were resected between 1992 and 2016. Overall and major morbidity predictors were identified through multiple logistic regression. Models' performances were assessed through discrimination, calibration, and cross-validation, and nomograms were constructed. RESULTS: The mean age was 61.3-year old and the male gender was more frequent (60%). The most common comorbidities were hypertension (HTN), diabetes, and chronic obstructive pulmonary disease (COPD). A D2-distal gastrectomy was the most frequent procedure and 87% of all lesions were located in the middle or distal third. Age, COPD, coronary heart disease, chronic liver disease, pancreatic resection, and operative time were independent predictors of overall and major morbidity. The extent of resection and splenectomy was associated with overall events and HTN with major ones. Both models were very effective in predicting events among patients at higher risk. CONCLUSIONS: The overall and major morbidity models and nomograms included clinical- and surgical-related data that were very effective in predicting events, especially for high-risk patients.

Is primary sidedness a prognostic factor in patients with resected colon cancer liver metastases (CLM)?

BACKGROUND AND OBJECTIVES: Recent studies have suggested that sidedness of origin from colorectal adenocarcinomas is a predictor of survival, however the impact of this factor in patients with resected colon cancer liver metastases (CLM) is not clear. So, in this study, we compared clinic and pathologic characteristics and long-term survival of patients with resected CLM according to the primary tumor location. METHODS: This is a retrospective analyzes of a prospective database. Patients with resected CLM from 1998 to 2012 were included. Right colon included tumors from cecum to middle transverse colon, and left colon included tumors from splenic flexure to sigmoid. RESULTS: One hundred fifty-one patients were included, 27 right colon and 124 left colon. In the latter group, there were more patients with synchronous disease (67.7 × 6.2%, P = 0.026) and a higher CEA (22.0 × 11.7 ng/mL, P = 0.001). However, K-Ras mutation was more frequent in right sided tumors (75.0 × 24.1%, P = 0.001). There was no difference in long term survival in both groups in this series even when adjusted for the confounding variables. CONCLUSION: Sidedness do not seem to be a predictor of long term survival in patients with resected colon cancer liver metastases.

Role of staging laparoscopy in the management of Pancreatic Duct Carcinoma (PDAC): Single-center experience from a tertiary hospital in Brazil.

BACKGROUND: Proper staging is critical to the management of pancreatic ductal carcinoma (PDAC). Laparoscopy has been used to stage patients without gross metastatic disease with variable success. OBJECTIVES: We aimed to identify the frequency of patients diagnosed by laparoscopy with occult metastatic disease. Also, we looked for variables related to a higher chance of occult metastasis. METHODS: Patients with PDAC submitted to staging laparoscopy either immediately before pancreatectomy or as a separate procedure between January 2010 and December 2016 were included. None presented gross metastatic disease at initial staging. We used logistic regression to search for variables associated with metastatic disease. RESULTS: The study population consisted of 63 patients. Among all patients, nine (16.7%) had occult metastases at laparoscopy. Unresectable tumor (Odds ratio = 18.0, P = 0.03), increasing tumor size (Odds ratio = 1.36, P = 0.01), and abdominal pain (Odds ratio = 5.6, P = 0.04) significantly predicted the risk of occult metastases in univariate analysis. In multivariate analysis, only tumor size predicted the risk of occult metastases. CONCLUSION: Laparoscopy remains a valuable tool in PDAC staging. Patients with either large or unresectable tumors, or presenting with abdominal pain present the highest risk for occult intra-abdominal metastases.

Neoadjuvant intraperitoneal chemotherapy followed by radical surgery and HIPEC in patients with very advanced gastric cancer and peritoneal metastases: report of an initial experience in a western single center.

BACKGROUND: The association of preoperative systemic and intraperitoneal chemotherapy has been described in Eastern patients with very good outcomes in treatment responders. The aim of this paper is to describe the initial results of this multidisciplinary regimen in gastric cancer patients with very advanced peritoneal metastases. CASE PRESENTATION: We present here the first four cases who received the treatment protocol. They had a baseline PCI between 19 and 33. Two patients had received systemic chemotherapy prior to this regimen. Three of them had significant response and were taken to cytoreductive surgery, while one patient who had 12 cycles of chemotherapy previously showed signs of disease progression and subsequently died. There was no significant postoperative morbidity, and three patients remain alive, two of them with no signs of recurrence. CONCLUSION: Systemic and intraperitoneal chemotherapy led to a marked response in peritoneal disease extent in our initial experience and allowed three of four patients with very advanced disease to be treated with cytoreductive surgery.

Noncurative Resection for Gastric Cancer Patients: Who Could Benefit? : Determining Prognostic Factors for Patient Selection.

BACKGROUND: Resections have long been recommended for patients with incurable gastric cancer. However, high morbidity rates and more efficient chemotherapy regimens have demanded more accurate patient selection. The aim of this study was to analyze the results of gastric cancer patients treated with noncurative resection in a single cancer center. METHODS: Medical charts of patients treated with a noncurative resection between January 1988 and December 2012 were analyzed. Individuals who had M1 disease were included, along with those with no metastasis but who had an R2 resection. Morbidity, mortality, and survival prognostic factors were analyzed. RESULTS: In the period, 192 patients were resected, 159 with previously diagnosed metastatic disease and the other 33 having resection with macroscopic residual disease (R2). A distal gastrectomy was performed in 117 patients and a total resection in 75, with a more limited lymph node dissection in 70 % of cases. A multivisceral resection was deemed necessary in 42 individuals (21.9 %). Overall morbidity was 26.6 % and 60-day mortality was 6.8 %. Splenectomy was the only independent prognostic factor for higher morbidity. Median survival was 10 months, and younger age, distal resection, and chemotherapy were independent prognostic factors for survival. A prognostic score obtained from these factors identified a 20-month median survival in patients with these favorable characteristics. CONCLUSION: Noncurative surgery may be considered in selected gastric cancer patients as long as it has low morbidity and allows the realization of chemotherapy.