The IASLC Pleural Mesothelioma Staging Project: Proposal for Revision of the TNM Stage Groupings in the Forthcoming (Ninth) Edition of the TNM Classification for Pleural Mesothelioma

INTRODUCTION

The eighth edition of the tumor, node and metastases (TNM) classification of pleural mesothelioma (PM) saw substantial changes in T and N components and stage groupings. The International Association for the Study of Lung Cancer collected data into a multinational database in order to further refine this classification. This 9th edition proposal incorporates changes proposed in the clinical (c)T component, but not the pathologic (p)T component, to include size criteria, and further refines TNM stage groupings for PM.

METHODS

Data were submitted via electronic data capture (EDC) or batch transfer from institutional databases. Survival was measured from diagnosis date. Candidate stage groups were developed using a recursive partitioning and amalgamation (RPA) algorithm applied to all cM0 cases for clinical stage and subsequently for pathological stage. Cox models were developed to estimate survival for each stage group.

RESULTS

Of 3598 submitted cases, 2192 were analyzable for overall cStage and 445 for overall pStage. RPA generated survival tree on OS outcomes restricted to cM0 with newly proposed (9th edition) cT and cN component-derived optimal stage groupings of: stage I (T1N0), II (T1N1; T2N0), IIIA (T1N2; T2N1/2; any T3), IIIB (any T4), and IV (any M1). Although cT and pT descriptors are different in the 9th edition, aligning pStage groupings with cStage produced better discrimination than retaining 8th edition pStage groupings.

CONCLUSIONS

This revision of the clinical TNM classification for PM is the first to incorporate the measurement-based proposed changes in clinical T category. The pathological TNM aligns with clinical TNM.

The IASLC Mesothelioma Staging Project: Proposals for the 'N' descriptors in the forthcoming 9th edition of the TNM classification for Pleural Mesothelioma

INTRODUCTION

The International Association for the Study of Lung Cancer developed an international database to inform potential revisions in the 9th edition of the Tumor, Node, Metastasis classification of diffuse pleural mesothelioma (PM). This study analyzed the clinical and pathological N categories to determine whether revisions were indicated relative to the 8th edition staging system.

METHODS

Of 7,338 PM cases diagnosed 2013 to 2022, 3,598 met all inclusion criteria for planned analyses. Data on 2,836 patients without metastases were included in this study. Overall survival (OS) was measured from date of diagnosis. Patients were included regardless of whether they received neoadjuvant treatment. For the pathological N analysis, patients who underwent resection (extrapleural pneumonectomy or pleurectomy/decortication) were included. N subgroups were analyzed and overall survival (OS) assessed by the Kaplan Meier method.

RESULTS

The existing 8th edition N categories performed adequately in the 9th edition dataset. A median OS advantage was noted for clinical and pathological N0 versus N1 patients: 23.2 versus 18.5 and 33.8 vs. 25.0 months, respectively. Patients with resected pN0 had a 3-year OS of 48%. No difference in OS was noted for single versus multiple station nodal metastases. The number of nodal stations sampled at the time of resection was not associated with a difference in OS.

CONCLUSIONS

Data regarding clinical and pathological N categories corroborate those used in the 8th edition. No changes in the N categories are recommended in the 9th edition of PM staging system.

Pleurectomy and decortication are associated with better survival for bicavitary cytoreductive surgery for mesothelioma compared with extrapleural pneumonectomy

OBJECTIVES

Mesothelioma is a nearly uniformly fatal tumor. Multimodality therapy including cytoreductive surgery and chemotherapy is associated with long-term survival in some patients. Cytoreductive surgery for thoracic disease includes a lung-sparing operation called an "extended pleurectomy/decortication" or a lung-sacrificing surgery called an "extrapleural pneumonectomy." The benefit of cytoreductive surgery for bicavitary disease (chest and abdomen) is poorly understood. Our objective was to evaluate the long-term survivals for patients undergoing cytoreductive surgery for bicavitary disease and to determine whether any prognostic factors were associated with outcome.

METHODS

We reviewed our Institutional Review Board-approved, institutional, International Association for the Study of Lung Cancer Mesothelioma Staging Project database. Inclusion criteria were all patients who underwent cytoreductive surgery for bicavitary disease. Overall survival was calculated by Kaplan-Meier methodology. All International Association for the Study of Lung Cancer database elements were evaluated by univariable analysis.

RESULTS

From February 2014 to August 2021, 440 patients with mesothelioma were evaluated. Fourteen patients (3%) underwent cytoreductive surgery of both chest and abdomen as a planned 2-stage operation. Most patients (13/14; 93%) underwent chest surgery before abdomen surgery. For the entire cohort, the median overall survival was 33.6 months with a 5-year survival of 20%. Extended pleurectomy/decortication was associated with a better outcome compared with extrapleural pneumonectomy, with median overall survivals of 58.2 versus 13.5 months, respectively.

CONCLUSIONS

For a highly selected group of patients with bicavitary mesothelioma, long-term survival can be achieved with an aggressive, staged surgical approach. The patients who undergo extended pleurectomy/decortication with preservation of the lung appear to have more favorable outcomes compared with patients undergoing extrapleural pneumonectomy.

A Phase II Window of Opportunity Study of Neoadjuvant PD-L1 versus PD-L1 plus CTLA-4 Blockade for Patients with Malignant Pleural Mesothelioma

PURPOSE

We report the results of a phase II, randomized, window-of-opportunity trial of neoadjuvant durvalumab versus durvalumab plus tremelimumab followed by surgery in patients with resectable malignant pleural mesothelioma (MPM; NCT02592551).

PATIENTS AND METHODS

The primary objective was alteration of the intratumoral CD8/regulatory T cell (Treg) ratio after combination immune checkpoint blockade (ICB) therapy. Secondary and exploratory objectives included other changes in the tumor microenvironment, survival, safety, tumor pathologic response (PR), and systemic immune responses.

RESULTS

Nine patients received monotherapy and 11 received combination therapy. Seventeen of the 20 patients (85%) receiving ICB underwent planned thoracotomy. Both ICB regimens induced CD8 T-cell infiltration into MPM tumors but did not alter CD8/Treg ratios. At 34.1 months follow-up, patients receiving combination ICB had longer median overall survival (not reached) compared with those receiving monotherapy (14.0 months). Grade ≥3 immunotoxicity occurred in 8% of patients in the monotherapy group and 27% of patients in the combination group. Tumor PR occurred in 6 of 17 patients receiving ICB and thoracotomy (35.3%), among which major PR (>90% tumor regression) occurred in 2 (11.8%). Single-cell profiling of tumor, blood, and bone marrow revealed that combination ICB remodeled the immune contexture of MPM tumors; mobilized CD57+ effector memory T cells from the bone marrow to the circulation; and increased the formation of tertiary lymphoid structures in MPM tumors that were rich in CD57+ T cells.

CONCLUSIONS

These data indicate that neoadjuvant durvalumab plus tremelimumab orchestrates de novo systemic immune responses that extend to the tumor microenvironment and correlate with favorable clinical outcomes.

Targeting mutant p53-R248W reactivates WT p53 function and alters the onco-metabolic profile

TP53 is the most commonly mutated gene in cancer, and gain-of-function mutations have wide-ranging effects. Efforts to reactivate wild-type p53 function and inhibit mutant functions have been complicated by the variety of TP53 mutations. Identified from a screen, the NSC59984 compound has been shown to restore activity to mutant p53 in colorectal cancer cells. Here, we investigated its effects on esophageal adenocarcinoma cells with specific p53 hot-spot mutations. NSC59984 treatment of cells reactivated p53 transcriptional regulation, inducing mitochondrial intrinsic apoptosis. Analysis of its effects on cellular metabolism demonstrated increased utilization of the pentose phosphate pathway and inhibition of glycolysis at the fructose-1,6-bisphosphate to fructose 6-phosphate junction. Furthermore, treatment of cells with NSC59984 increased reactive oxygen species production and decreased glutathione levels; these effects were enhanced by the addition of buthionine sulfoximine and inhibited by N-acetyl cysteine. We found that the effects of NSC59984 were substantially greater in cells harboring the p53 R248W mutation. Overall, these findings demonstrate p53-dependent effects of NSC59984 on cellular metabolism, with increased activity in cells harboring the p53 R248W mutation. This research highlights the importance of defining the mutational status of a particular cancer to create a patient-centric strategy for the treatment of p53-driven cancers.

Inhibition of Cyclin Dependent Kinase 4/6 Overcomes Primary Resistance to Programmed Cell Death 1 Blockade in Malignant Mesothelioma

BACKGROUND

Despite the profound number of malignant pleural mesothelioma (MPM) patients now treated with programmed cell death 1 (PD-1) blockade, insight into the underpinnings of rational therapeutic strategies to treat resistance to checkpoint immunotherapy remains unrealized. Our objective was to develop a novel therapeutic approach to overcome primary resistance to PD-1 blockade in MPM.

METHODS

We generated a transcriptome signature of resistance to PD-1 blockade in MPM patients treated with nivolumab (4 responders and 4 nonresponders). We used The Cancer Genome Atlas MPM cohort (n = 73) to determine what genomic alterations were associated with the resistance signature. We tested whether regulation of identified molecules could overcome resistance to PD-1 blockade in an immunocompetent mouse malignant mesothelioma model.

RESULTS

Immunogenomic analysis by applying our anti-PD-1 resistance signature to The Cancer Genome Atlas cohort revealed that deletion of cyclin dependent kinase inhibitor 2A (CDKN2A) was highly associated with primary resistance to PD-1 blockade. Under the hypothesis that resistance to PD-1 blockade can be overcome by cyclin dependent kinase 4/6 (CDK4/6) inhibition, we tested whether CDK4/6 inhibitors could overcome resistance to PD-1 blockade in subcutaneous tumors derived from Cdkn2a-/- AB1 malignant mesothelioma cells, which were resistant to PD-1 blockade. The combination of daily oral administration of CDK4/6 inhibitors (abemaciclib or palbociclib) and intraperitoneal anti-PD-1 treatment markedly suppressed tumor growth compared with anti-PD-1 or CDK4/6 inhibitor alone.

CONCLUSIONS

We identified a therapeutic target, CDK4/6, to overcome primary resistance to PD-1 blockade through comprehensive immunogenomic approaches. These data provide a rationale for undertaking clinical trials of CDK4/6 inhibitors in more than 40% of patients with MPM who demonstrate loss of CDKN2A.

Therapeutic Targeting of Macrophage Plasticity Remodels the Tumor-Immune Microenvironment

SIGNIFICANCE

Comprehensive single-cell proteomics analyses of lung adenocarcinoma progression reveal the role of tumor-associated macrophages in resistance to PD-1 blockade therapy. See related commentary by Lee et al., p. 2515.

Characteristics of Matriculants to Thoracic Surgery Residency Training Programs

BACKGROUND

Thoracic surgery (TS) residency positions are in high demand. There is no study describing the nationwide attributes of successful matriculants in this specialty. We examined the characteristics of TS resident applicants and identified factors associated with acceptance.

METHODS

Applicant data from 2014 to 2017 application cycles was extracted from the Electronic Residency Application System and stratified by matriculation status. Medical education, type of general surgery residency, and research achievements were analyzed. The number of peer-reviewed publications and the corresponding impact factor for the journals where they were published were quantified.

RESULTS

There were 492 applicants and 358 matriculants. The overall population was primarily male (79.5%), white (55.1%), educated at United States allopathic medical schools (66.5%), and trained at university-based general surgery residencies (59.6%). Education at United States allopathic schools (odds ratio [OR], 2.54; P < .0001), being a member of the American Osteopathic Association (OR, 3.27; P = .021), general surgery residency affiliation with a TS residency (OR, 2.41; P = .0003) or National Cancer Institute designated Comprehensive Cancer Center (OR, 1.76; P = .0172), and being a first-time applicant (OR, 4.71, P < .0001) were independently associated with matriculation. Matriculants published a higher number of manuscripts than nonmatriculants (median of 3 vs 2, P < .0001) and more frequently published in higher impact journals (P < .0001).

CONCLUSIONS

Our study includes objective and quantifiable data from recent application cycles and represents an in-depth examination of applicants to TS residency. The type of medical school and residency, as well as academic productivity, correlate with successful matriculation.

Two distinct classes of thymic tumors in patients with MEN1 show LOH at the MEN1 locus

Patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome carry germline heterozygous loss-of-function mutations in the MEN1 gene which predisposes them to develop various endocrine and non-endocrine tumors. Over 90% of the tumors show loss of heterozygosity (LOH) at chromosome 11q13, the MEN1 locus, due to somatic loss of the wild-type MEN1 allele. Thymic neuroendocrine tumors (NETs) or thymic carcinoids are uncommon in MEN1 patients but are a major cause of mortality. LOH at the MEN1 locus has not been demonstrated in thymic tumors. The goal of this study was to investigate the molecular aspects of MEN1-associated thymic tumors including LOH at the MEN1 locus and RNA-sequencing (RNA-Seq) to identify genes associated with tumor development and potential targeted therapy. A retrospective chart review of 294 patients with MEN1 germline mutations identified 14 patients (4.8%) with thymic tumors (12 thymic NETs and 2 thymomas). LOH at the MEN1 locus was identified in 10 tumors including the 2 thymomas, demonstrating that somatic LOH at the MEN1 locus is also the mechanism for thymic tumor development. Unsupervised principal component analysis and hierarchical clustering of RNA-Seq data showed that thymic NETs formed a homogenous transcriptomic group separate from thymoma and normal thymus. KSR2 (kinase suppressor of Ras 2), that promotes Ras-mediated signaling, was abundantly expressed in thymic NETs, a potential therapeutic target. The molecular insights gained from our study about thymic tumors combined with similar data from other MEN1-associated tumors may lead to better surveillance and treatment of these rare tumors.

Randomized phase II trial of a first-in-human cancer cell lysate vaccine in patients with thoracic malignancies

BACKGROUND

Although most malignancies express cancer-testis antigens (CTA), immune responses to these proteins are limited in thoracic oncology patients. This trial was undertaken to examine if a cancer cell lysate vaccine could induce immunity to CTA, and to ascertain if metronomic cyclophosphamide and celecoxib enhances vaccine-induced immune responses.

METHODS

Eleven patients with primary thoracic malignancies and 10 patients with extrathoracic neoplasms metastatic to the chest rendered NED by conventional therapies were randomized to receive H1299 lung cancer cell lysates (10 mg protein/vaccine) with Iscomatrix™ adjuvant via deep intradermal injection q 4 weeks ×6 with or without daily oral metronomic cyclophosphamide/celecoxib. The primary endpoint was serologic response to purified CTA assessed 1 month after the 6th vaccination. Secondary endpoints included assessment of the effects of cyclophosphamide and celecoxib on frequency and magnitude of vaccine-induced immune responses to CTA. Exploratory endpoints included evaluation of the effects of the vaccine regimens on peripheral immune subsets. Standard of care imaging studies were obtained at baseline and 1 month after the 3rd and 6th vaccinations.

RESULTS

All patients exhibited local and systemic inflammatory responses lasting 72-96 hours following vaccinations. There were no dose limiting treatment related toxicities. Fourteen patients (67%) completed all six vaccinations. Eight of 14 patients (57%) exhibited serologic responses to NY-ESO-1. One patient developed antibodies to GAGE7; several patients exhibited reactivity to XAGE and MAGE-C2. Vaccine therapy decreased the percent of Tregs (P=0.0068), PD-1 expression on Tregs (P=0.0027), PD-L1 expression on CD14+ monocytes (P=0.0089), PD-L1 expression on classical monocytes (P=0.016), and PD-L1 expression on intermediate monocytes (P=0.0031). Cyclophosphamide/celecoxib did not appear to increase immune responses or enhance vaccine-induced alterations in peripheral immune subsets.

CONCLUSIONS

H1299 lysate vaccines with Iscomatrix™ induce immune responses to CTA and modulate peripheral immune subsets in a manner that may enhance antitumor immunity in patients with thoracic malignancies.

Anti-PD-1 monotherapy in patients with malignant mesothelioma: A retrospective single institution experience

e20564

Background: Malignant mesothelioma (MM) patients historically have poor outcomes, but immune checkpoint inhibitors have shown promising results in certain patients. We aimed to retrospectively assess efficacy and safety with use of anti-PD-1 monotherapy (aPD-1 Tx) in patients with MM at our institution from Dec 2015 to Dec 2020. Methods: We identified patients with MM treated with nivolumab or pembrolizumab. Clinical details including demographics, efficacy, and toxicity were collected. Efficacy was characterized based on overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). Survival curves were generated using the Kaplan-Meier method, and intergroup comparisons were performed with the log-rank test. Univariable Cox regression analysis was used to determine whether variables were associated with survival. Results: We identified 61 patients treated with aPD-1 Tx for MM. Majority of patients (90%) had malignant pleural mesothelioma. Forty-two (69%) patients were male. The median age of initiation was 65 years (range: 30-84). Most patients (66%) had an ECOG performance status (PS) of 0-1. Known asbestos exposure was noted in 19 (31%) patients. Most patients had received prior chemotherapy (74%) and treated with nivolumab (89%). Only 66% of patients with known PD-L1 had positive expression ( > = 1%). There were 43 (70%) patients with epithelioid histology. Median follow-up was 22.2 months. ORR was 33% with stable disease in 25% of patients. In first-line aPD-1 Tx, ORR was 50%. PFS and OS at 12 months were 26% and 65%, respectively. The median PFS and OS were 5.1 and 15.6 months, respectively. PD-L1 positivity was not associated with improved PFS or OS. Univariable analysis demonstrated that ECOG PS 0-1 had significantly better OS with hazard ratio (HR) 0.40 (95% CI 0.20 – 0.83; p = 0.01). Immune-related adverse events (irAE) were seen in 33% of patients with 13 patients with grade 3 or higher (nephritis, pneumonitis, arthritis, leukocytosis, dermatitis, colitis, type 1 diabetes mellitus, tongue angioedema, and thrombocytopenia). One patient had grade 5 irAE due to severe thrombocytopenia. Patients who developed an irAE had significantly improved median OS (32.1 vs 12.1 months, p = 0.01). Conclusions: Anti-PD-1 monotherapy showed clinical efficacy and safety in malignant mesothelioma as both a first-line treatment and in pre-treated patients based on our real-world experience. The development of irAE may predict benefit, although fatal side effects can occur.

Video-assisted thoracoscopic surgery pleurectomy: a suitable alternative for treating malignant pleural effusions

Background

Malignant pleural effusions (MPEs) are common manifestations of metastatic cancers and are associated with a dismal prognosis. Talc pleurodesis has been proven to be effective in the management of MPEs, however, class-action lawsuits linking talc to ovarian adenocarcinoma have rendered it unavailable at many institutions. As a result, surgeons have resorted to less effective chemical pleurodesis as an alternative to indwelling pleural drainage catheters. Given the absence of talc, we explored the effectiveness of video-assisted thoracoscopic surgery (VATS) partial pleurectomy (VPP) for treating MPEs.

Methods

We performed a retrospective review of patients with MPEs managed after talc became unavailable at our institution. Between 2016 and 2018, we identified five patients who refused pleural drainage catheters and underwent VPP. Symptoms at presentation included fatigue, dyspnea, and pleuritic chest pain. All had unilateral MPEs (left n=3, right n=2). VPP included removal of parietal surfaces of the pleura other than the pleura overlying the subclavian vessels, the mediastinum, and the lung viscera.

Results

There were no significant perioperative adverse events and post-operative pain was well controlled. Chest tubes were removed between post-operative day (POD) 3 and 7. Follow-up time ranged from four to 36 weeks. All patients had symptomatic relief and radiographic evidence of improved MPEs. No patients required re-interventions. One patient expired six months after surgery while the remaining four were alive at last follow-up.

Conclusions

VPP offers an effective alternative to chemical pleurodesis for managing MPEs in patients who prefer to avoid pleural drainage catheters.

Diagnostic Laparoscopy Improves Staging of Malignant Pleural Mesothelioma With Routine Positron Emission Tomography Imaging

BACKGROUND

With a multimodal treatment strategy, cytoreductive surgery extends survival in malignant pleural mesothelioma. Improving the accuracy of staging can refine patient selection. Our objective was to determine whether diagnostic laparoscopy (DL) improves staging for patients with malignant pleural mesothelioma with the routine use of positron emission tomography (PET).

METHODS

We performed a retrospective review of our prospectively maintained database from February 2014 to May 2019. Inclusion criteria were patients who had disease in the chest that was deemed potentially resectable by radiographic criteria and who underwent DL as part of the staging evaluation before surgery.

RESULTS

Of 187 patients (71% men, 80% epithelial) who underwent DL during staging, 76% proceeded to surgery; 22% were unresectable at exploratory thoracotomy and 78% underwent resection (pleurectomy and decortication, 68%; extrapleural pneumonectomy, 32%). Also, 89% had a PET computed tomography (CT), and 11% had a preoperative CT without PET. DL revealed peritoneal disease in 17%. Among patients with pathologically proven disease at DL, 77% had negative PET-CT imaging. Based on the pathologic findings at DL the sensitivity, specificity, positive predictive value, and negative predictive value of PET-CT were 23%, 78%, 17%, and 83%, respectively. The accuracy of PET-CT was 68%.

CONCLUSIONS

PET-CT has low sensitivity and diagnostic accuracy to identify peritoneal disease in malignant pleural mesothelioma. DL as part of the preoperative staging defines an important subset of patients with bicavitary disease. We recommend DL as a component of staging before surgery.

Correction to: Rates of TP53 Mutation are Significantly Elevated in African American Patients with Gastric Cancer

In the original article Kaitlin C. McLoughlin's name is spelled incorrectly. It is correct as reflected here.

Prognostic Role of Programmed Cell Death 1 Ligand 1 in Resectable Pleural Mesothelioma

BACKGROUND

The prognostic role of programmed cell death 1 ligand 1 (PD-L1) in malignant pleural mesothelioma (MPM) is incompletely understood. Our objectives were to evaluate the evidence for tumor PD-L1 as a prognostic biomarker in MPM through meta-analysis and to determine whether tumor PD-L1 expression is associated with survival in MPM patients undergoing macroscopic complete resection.

METHODS

Meta-analysis was performed to determine the association of PD-L1 with overall survival in MPM (n = 1655) from 14 studies containing overall survival and tumor PD-L1 expression. Univariable and multivariable analyses tested the relationship of tumor PD-L1 with overall survival and recurrence-free survival in an institutional cohort of MPM patients treated by macroscopic complete resection (n = 75). To validate the association of PD-L1 with overall survival, we utilized two independent MPM cohorts (n = 284).

RESULTS

Meta-analysis demonstrated that high tumor PD-L1 expression was associated with poor overall survival. Among 75 patients undergoing macroscopic complete resection, 49 tumors (65%) expressed PD-L1 (1% or more), and high PD-L1 (50% or greater) was more commonly expressed on nonepithelial (29%) compared with epithelial tumors (14%). High tumor PD-L1 expression was independently associated with poor overall survival (P < .001, hazard ratio 5.67) and recurrence-free survival (P = .003, hazard ratio 3.28). The association of PD-L1 overexpression with unfavorable survival was more significant in epithelial MPMs than nonepithelial MPMs. These findings were validated in RNA sequencing analyses in two independent cohorts. Exploratory transcriptome analysis revealed that MPM tumors with PD-L1 overexpression displayed coexpression of other immune regulatory molecules, programmed cell death 1 ligand 2 and T-cell immunoglobulin mucin receptor 3.

CONCLUSIONS

Tumor PD-L1 expression is a prognostic biomarker in patients undergoing surgical resection for MPM and may be useful in perioperative decision making.

Extended Pleurectomy and Decortication for Malignant Pleural Mesothelioma

Extended pleurectomy and decortication (ePD) is a difficult operation performed for the surgical resection of malignant pleural mesothelioma that can achieve a macroscopic complete resection with preservation of the lung. With lower perioperative mortality, similar long-term survival, and better tolerance in patients with lower performance status, ePD has become the preferred operation rather than extrapleural pneumonectomy despite lack of a direct comparison. As ePD has become more popular, international collaboration is underway to create surgical guidelines based on collection of operative data. These efforts will improve the safety and standardization of this operation.

The Staging of Malignant Pleural Mesothelioma

Staging of malignant pleural mesothelioma has been challenging because of a paucity of cases and poor survival. At least 5 staging systems were proposed before 1990 until the first consensus system was published in 1995. This system used tumor, node, metastasis designations and borrowed heavily from parenchymal lung cancer descriptors. With the establishment of a database to collect cases from 1995 to 2013, evidence-based revisions to the 1995 staging classification were published in 2016. With improving imaging technology, clinical staging will become more refined and, it is hoped, more useful for prognostication even without operative resection.

Trends in Major Gastrectomy for Cancer: Frequency and Outcomes

BACKGROUND

Declining incidence of gastric cancer in the USA has presumably resulted in lower rates of major gastrectomy for cancer. The impact on perioperative outcomes remains undefined. The aims of this study were to characterize national trends in frequency of major gastrectomy for cancer, identify factors associated with in-hospital mortality, and examine outcome disparities by race/ethnicity.

METHODS

Nationwide inpatient sample data from 1993 to 2013 were queried for procedural and diagnostic codes (ICD-9) relating to total and partial gastrectomy procedures. Gastric resections for cancer were compared to those for peptic ulcer disease for reference. Patient demographics, comorbidity score, mortality, and hospital characteristics were recorded as covariates.

RESULTS

A significant decrease in annual rates of partial and total gastrectomy was observed from 1993 to 2013 (p < 0.0001). The change in absolute number and percent decline was greater for partial gastrectomy (- 39.3%) than total gastrectomy (- 19%). There was a 34.0% decrease in gastrectomy for cancer in Whites and a 61.2% increase among Hispanic patients over two decades. In-hospital mortality also significantly decreased over the study period (7.7% to 2.7%). Factors associated with lower mortality rates included male sex and treatment at urban teaching hospitals. Analysis of trends revealed that gastrectomy for cancer was performed with increasing frequency at urban teaching hospitals.

CONCLUSIONS

The frequency of major gastric resections in the USA has declined over two decades. Overall, in-hospital mortality rates also have decreased significantly. Declining in-hospital mortality after gastrectomy for cancer is associated with more frequent treatment at urban teaching hospitals.

MicroRNA-215-5p Treatment Suppresses Mesothelioma Progression via the MDM2-p53-Signaling Axis

Malignant pleural mesothelioma (MPM) is an incurable, aggressive neoplasm with distinctive features, including preservation of wild-type p53, irrespective of histologic subtype. We posited that this consistent molecular characteristic represents an underexploited therapeutic target that can be approached by leveraging biologic effects of microRNA (miRNA). The Cancer Genome Atlas was surveyed to identify p53-responsive prognostic miRNA(s) in MPM. Using patient samples, in vitro MPM cell lines, and murine tumor xenograft models, we verified specific gene pathways targeted by these miRNAs, and we examined their therapeutic effects. miR-215-5p is a poor prognosis miRNA downregulated in MPM tissues, which has not been recognized previously. When miR-215-5p was ectopically re-expressed in MPM cells and delivered in vivo to tumor xenografts, it exerted significant cell killing by activating p53 function and inducing apoptosis. The mechanistic basis for this effect is due to combinatorial effects of a positive feedback loop of miR-215-MDM2-p53 signaling, additional mouse double minute 2 (MDM2)-p53 positive feedback loop(s) with other miRNAs such as miR-145-5p, and suppression of diverse gene targets associated with cell cycle dynamics not previously drug treatable in MPM clinical studies. Our results suggest a potential pathophysiologic role for and therapeutic significance of miR-215-5p in MPM.

Metadherin Is a Prognostic Apoptosis Modulator in Mesothelioma Induced via NF-κB-Mediated Signaling

Therapies against malignant pleural mesothelioma (MPM) have yielded disappointing results, in part, because pathologic mechanisms remain obscure. In searching for rational molecular targets, we identified metadherin (MTDH), a multifunctional gene associated with several tumor types but previously unrecognized in MPM. Cox proportional hazards regression analysis delineated associations between higher MTDH expression and lower patient survival from three independent MPM cohorts (n = 349 patients). Through in vitro assays with overexpression and downregulation constructs in MPM cells, we characterized the role of MTDH. We confirmed in vivo the phenotype of altered MTDH expression in a murine xenograft model. Transcriptional regulators of MTDH were identified by chromatin immunoprecipitation. Overexpression of both MTDH mRNA (12-fold increased) and protein levels was observed in tumor tissues. MTDH stable overexpression significantly augmented proliferation, invasiveness, colony formation, chemoresistance, and an antiapoptosis phenotype, while its suppression showed opposite effects in MPM cells. Interestingly, NF-κB and c-Myc (in a feed-forward loop motif) contributed to modulating MTDH expression. Knockdown of MTDH expression profoundly retarded xenograft tumor growth. Thus, our findings support the notion that MTDH integrates upstream signals from certain transcription factors and mediates pathogenic interactions contributing to MPM traits. MTDH represents a new MPM-associated gene that can contribute to insights of MPM biology and, as such, suggest other treatment strategies.

A Phase II Trial of Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy for Recurrent Adrenocortical Carcinoma

BACKGROUND

Recurrent adrenocortical carcinoma (ACC) is an aggressive disease with few options offering durable survival benefit. Despite metastasectomy, recurrence is common. Cytoreduction and intraperitoneal chemotherapy have offered improved survival in other advanced cancers. We sought to evaluate the use of cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) for the treatment of recurrent intraperitoneal ACC.

METHODS

A phase II, single institution clinical trial was approved for patients with radiographic evidence of resectable ACC limited to the peritoneum. Patients underwent treatment if optimal cytoreduction was deemed possible at exploratory laparotomy. Primary outcome was intraperitoneal progression-free survival. Secondary outcomes were treatment-related morbidities and overall survival.

RESULTS

Sixty-three patients were evaluated, of whom 11 met eligibility criteria. Nine patients underwent cytoreduction and HIPEC, including one patient who recurred and was re-treated (n = 10 treatments). One patient could not be optimally cytoreduced for HIPEC and therefore did not receive intraperitoneal chemotherapy. There was no perioperative mortality; perioperative comorbidities were limited to Clavien-Dindo grade 2 or 3 and included hematologic, infectious, and neurologic complications. Seven patients experienced disease recurrence and two patients died of disease during follow-up (median 24 mo). Intraperitoneal progression-free survival was 19 mo, and median overall survival has not yet been reached.

CONCLUSIONS

Cytoreduction and HIPEC can be performed safely in selected patients. Patients with recurrent ACC confined to the peritoneal cavity can be considered for regional therapy in experienced hands. However, disease recurrence is common, and other treatment options should be explored.