Clinical Impact of Positive Surgical Margins in Gastric Adenocarcinoma in the Era of Preoperative Therapy.

BACKGROUND: Microscopically positive (R1) surgical margins after gastrectomy increase gastric cancer recurrence risk, but optimal management after R1 gastrectomy is controversial. We sought to identify the impact of R1 margins on recurrence patterns and survival in the era of preoperative therapy for gastric cancer. METHODS: Patients who underwent gastrectomy for adenocarcinoma during 1998-2017 at a major cancer center were enrolled. Clinicopathologic factors associated with positive margins were examined, and incidence, sites, and timing of recurrence and survival outcomes were compared between patients with positive and negative margins. RESULTS: Of 688 patients, 432 (63%) received preoperative therapy. Thirty-four patients (5%) had R1 margins. Compared with patients with negative margins, patients with R1 margins more frequently had aggressive clinicopathologic features, such as linitis plastica (odds ratio [OR] 7.79, p < 0.001) and failure to achieve cT downstaging with preoperative treatment (OR 5.20, p = 0.005). The 5 year overall survival (OS) rate was lower in patients with R1 margins (6% vs 60%; p < 0.001), and R1 margins independently predicted worse OS (hazard ratio 2.37, 95% CI 1.51-3.75, p < 0.001). Most patients with R1 margins (58%) experienced peritoneal recurrence, and locoregional recurrence was relatively rare in this group (14%). Median time to recurrence was 8.5 months for peritoneal dissemination and 15.7 months for locoregional recurrence. CONCLUSION: R1 margins after gastrectomy were associated with aggressive tumor biology, high incidence of peritoneal recurrence after a short interval, and poor OS. In patients with R1 margins, re-resection to achieve microscopically negative margins has to be considered with caution.

Men1 maintains exocrine pancreas homeostasis in response to inflammation and oncogenic stress.

A more comprehensive understanding of the molecular mechanisms underlying pancreatic diseases, including pancreatitis and cancer, is essential to improve clinical management. MEN1 has established roles in epigenetic regulation and tumor suppression in the endocrine pancreas; however, intriguing recent data suggest MEN1 may also function in the exocrine pancreas. Using physiologically relevant genetic mouse models, we provide direct evidence that Men1 is essential for exocrine pancreas homeostasis in response to inflammation and oncogenic stress. Men1 loss causes increased injury and impaired regeneration following acute caerulein-induced pancreatitis, leading to more severe damage, loss of the normal acinar compartment, and increased cytokeratin 19-positive metaplasias and immune cell infiltration. We further demonstrate the Men1 protein is stabilized in response to insult, and loss of Men1 is associated with the overexpression of proinflammatory Jund target genes, suggesting that loss of Men1-mediated repression of Jund activity is, at least in part, responsible for the impaired response. Finally, we demonstrate that Men1 loss significantly accelerates mutant Kras-dependent oncogenesis. Combined, this work establishes Men1 as an important mediator of pancreas homeostasis in vivo.

Neoadjuvant chemotherapy for high-risk intrahepatic cholangiocarcinoma - does pathologic response mean better outcomes?

BACKGROUND: The role of neoadjuvant chemotherapy (NAC) in the management of intrahepatic cholangiocarcinoma (ICC) remains unknown. We sought to evaluate our experience treating high-risk ICC with NAC and to determine the prognostic significance of pathologic response. METHODS: Patients with ICC treated with NAC and surgery were analyzed using a prospectively maintained database. Pathologic response was graded by a blinded pathologist. Clinicopathologic/treatment variables were evaluated for associations with survival. RESULTS: Among 45 patients who received NAC followed by hepatectomy for high-risk ICC, 32(71%) were considered stage III, and 6(13%) were considered stage IV at time of diagnosis. Major response was identified in 39% of cases, including 2 with pathologic complete response. Patients with major response had a longer median NAC duration than patients with minor response (6 vs 4cycles, P=0.02). Regimen (gemcitabine/cisplatin vs gemcitabine/cisplatin/nab-paclitaxel) was not associated with response rate. Median recurrence-free (RFS) and overall survival (OS) were 11 and 45 months. Pathologic response was not associated with improved survival. CONCLUSION: Pathologic response to NAC was not associated with survival in this highly selected cohort. Nonetheless, the extended OS experienced by these high-risk patients is encouraging and suggests that NAC may help select patients who stand to benefit from aggressive resection.

YAP1 mediates gastric adenocarcinoma peritoneal metastases that are attenuated by YAP1 inhibition.

OBJECTIVE: Peritoneal carcinomatosis (PC; malignant ascites or implants) occurs in approximately 45% of advanced gastric adenocarcinoma (GAC) patients and associated with a poor survival. The molecular events leading to PC are unknown. The yes-associated protein 1 (YAP1) oncogene has emerged in many tumour types, but its clinical significance in PC is unclear. Here, we investigated the role of YAP1 in PC and its potential as a therapeutic target. METHODS: Patient-derived PC cells, patient-derived xenograft (PDX) and patient-derived orthotopic (PDO) models were used to study the function of YAP1 in vitro and in vivo. Immunofluorescence and immunohistochemical staining, RNA sequencing (RNA-Seq) and single-cell RNA-Seq (sc-RNA-Seq) were used to elucidate the expression of YAP1 and PC cell heterogeneity. LentiCRISPR/Cas9 knockout of YAP1 and a YAP1 inhibitor were used to dissect its role in PC metastases. RESULTS: YAP1 was highly upregulated in PC tumour cells, conferred cancer stem cell (CSC) properties and appeared to be a metastatic driver. Dual staining of YAP1/EpCAM and sc-RNA-Seq revealed that PC tumour cells were highly heterogeneous, YAP1high PC cells had CSC-like properties and easily formed PDX/PDO tumours but also formed PC in mice, while genetic knockout YAP1 significantly slowed tumour growth and eliminated PC in PDO model. Additionally, pharmacologic inhibition of YAP1 specifically reduced CSC-like properties and suppressed tumour growth in YAP1high PC cells especially in combination with cytotoxics in vivo PDX model. CONCLUSIONS: YAP1 is essential for PC that is attenuated by YAP1 inhibition. Our data provide a strong rationale to target YAP1 in clinic for GAC patients with PC.

Targeting cancer stem cells with a pan-BCL-2 inhibitor in preclinical and clinical settings in patients with gastroesophageal carcinoma.

OBJECTIVE: Gastro-oesophageal cancers (GEC) are resistant to therapy and lead to poor prognosis. The cancer stem cells (CSCs) and antiapoptotic pathways often confer therapy resistance. We sought to elucidate the antitumour action of a BCL-2 inhibitor, AT101 in GEC in vitro, in vivo and in a clinical trial. METHODS: Extensive preclinical studies in vitro and in vivo were carried out to establish the mechanism action of AT101 on targeting CSCs and antiapoptotic proteins. A pilot clinical trial in patients with GEC was completed with AT-101 added to standard chemoradiation. RESULTS: Overexpression of BCL-2 and MCL-1 was noted in gastric cancer tissues (GC). AT-101 induced apoptosis, reduced proliferation and tumour sphere formation in MCL-1/BCL-2 high GC cells. Interestingly, AT101 dramatically downregulated genes (YAP-1/Sox9) that control CSCs in GEC cell lines regardless of BCL-2/MCL-1 expression. Addition of docetaxel to AT-101 amplified its antiproliferation and induced apoptosis effects. In vivo studies confirmed the combination of AT101 and docetaxel demonstrated stronger antitumour activity accompanied with significant decrease of CSCs biomarkers (YAP1/SOX9). In a pilot clinical trial, 13 patients with oesophageal cancer (EC) received AT101 orally concurrently with chemoradiation. We observed dramatic clinical complete responses and encouraging overall survival in these patients. Clinical specimen analyses revealed that AT-101 dramatically reduced the expression of CSCs genes in treated EC specimens indicating antitumour activity of AT101 relies more on its anti-CSCs activity. CONCLUSIONS: Our preclinical and clinical data suggest that AT-101 overcomes resistance by targeting CSCs pathways suggesting a novel mechanism of action of AT101 in patients with GEC.

Integrated genomic profiling and modelling for risk stratification in patients with advanced oesophagogastric adenocarcinoma.

OBJECTIVE: Prognosis of patients with advanced oesophagogastric adenocarcinoma (mEGAC) is poor and molecular determinants of shorter or longer overall survivors are lacking. Our objective was to identify molecular features and develop a prognostic model by profiling the genomic features of patients with mEGAC with widely varying outcomes. DESIGN: We profiled 40 untreated mEGACs (20 shorter survivors <13 months and 20 longer survivors >36 months) with whole-exome sequencing (WES) and RNA sequencing and performed an integrated analysis of exome, transcriptome, immune profile and pathological phenotypes to identify the molecular determinants, developing an integrated model for prognosis and comparison with The Cancer Genome Atlas (TCGA) cohorts. RESULTS: KMT2C alterations were exclusively observed in shorter survivors together with high level of intratumour heterogeneity and complex clonal architectures, whereas the APOBEC mutational signatures were significantly enriched in longer survivors. Notably, the loss of heterozygosity in chromosome 4 (Chr4) was associated with shorter survival and 'cold' immune phenotype characterised by decreased B, CD8, natural killer cells and interferon-gamma responses. Unsupervised transcriptomic clustering revealed a shorter survivor subtype with distinct expression features (eg, upregulated druggable targets JAK2, MAP3K13 and MECOM). An integrated model was then built based on clinical variables and the identified molecular determinants, which significantly segregated shorter and longer survivors. All the above features and the integrated model have been validated independently in multiple TCGA cohorts. CONCLUSION: This study discovered novel molecular features prognosticating overall survival in patients with mEGAC and identified potential novel targets in shorter survivors.

Genomic profiling of multifocal intrahepatic cholangiocarcinoma reveals intraindividual concordance of genetic alterations.

In multifocal intrahepatic cholangiocarcinoma (IHC), intrahepatic metastases (IM) represent a contraindication to surgical resection, whereas satellite nodules (SN) do not. However, no consensus criteria exist to distinguish IM from SN. The purpose of this study was to determine genetic alterations and clonal relationships in surgically resected multifocal IHC. Next-generation sequencing of 34 spatially separated IHC tumors was performed using a targeted panel of 201 cancer-associated genes. Proposed definitions in the literature were applied of SN located in the same liver segment and ≤2 cm from the primary tumor; and IM located in a different liver segment and/or >2 cm from the primary tumor. Somatic point mutations concordant across tumors from individual patients included BAP1, SMARCA4 and IDH1. Small insertions and deletions (indels) present at the same genome positions among all tumors from individuals included indels in DNA repair genes, CHEK1, ERCC5, ATR and MSH6. Copy number alterations were also similar between all tumors in each patient. In this cohort of multifocal IHC, genomic profiles were concordant across all tumors in each patient, suggesting a common progenitor cell origin, regardless of the location of tumors in the liver. The decision to perform surgery should not be based upon a perceived distinction between IM and SN.

Cancer of Unknown Primary Presenting as Bone-Predominant or Lymph Node-Only Disease: A Clinicopathologic Portrait.

BACKGROUND: Cancer of unknown primary (CUP) presenting as bone-predominant (BCUP) or lymph node-only disease (LNCUP) represents two clinically distinct subsets of nonvisceral CUP. These present a diagnostic challenge with a large differential of putative primary cancers and defy the "one-treatment-fits-all" approach. MATERIALS AND METHODS: We identified patients with BCUP (n = 29) and LNCUP (n = 63) using a prospectively collected CUP database and tumor registry of patients seen at MD Anderson Cancer Center between 2001 to 2017. Clinicopathological characteristics, treatments, and outcomes were abstracted. A control group of non-BCUP/LNCUP cases (n = 443) from the database was used for comparison. Kaplan-Meier method was used to estimate overall survival and compared using log-rank test. RESULTS: In this cohort, 64% and 60% patients had disseminated disease at diagnosis and 39% and 23% had Culine poor-risk disease in BCUP and LNCUP, respectively. Median overall survival (OS) for BCUP was 14.5 months and for LNCUP was 32.6 months. For BCUP, gemcitabine plus platinum was the most common initial chemotherapy (54%). For LNCUP, carboplatin plus paclitaxel was the most common initial chemotherapy (38%). Radiation was given to 74% of patients with BCUP and 37% of those with LNCUP. On multivariate analysis, poor-risk Culine group (hazard ratio [HR], 1.76; p < .001) and high neutrophil-to-lymphocyte ratio (HR, 2.38, p < .001) were associated with worse OS. CONCLUSION: BCUP and LNCUP are rare subsets within CUP with varying prognosis. Poor-risk Culine group and high neutrophil-to-lymphocyte ratio are associated with poor survival. Select patients with limited metastases can have long-term survival with aggressive multimodality treatment. Careful clinicopathological review can facilitate chances of site-directed therapy. IMPLICATIONS FOR PRACTICE: Cancer of unknown primary (CUP) rarely presents as bone-predominant (BCUP) or lymph node-only (LNCUP) disease. This article describes a cohort of each and compares with a larger CUP cohort. Patients with BCUP have unique issues with fractures and pain, often receiving radiation. Overall survival of 14.5 months was similar to a larger CUP comparison cohort. Patients with LNCUP had improved overall survival at 32.6 months, with longer survival in patients without disseminated disease. Culine poor-risk group and neutrophil-to-lymphocyte ratio were associated with worse overall survival. Tips regarding diagnosis and management of these rare malignant subsets are provided.

Intestinal Epithelial TBK1 Prevents Differentiation of T-helper 17 Cells and Tumorigenesis in Mice.

BACKGROUND & AIMS: Intestinal epithelial cells (IECs) regulate intestinal immune cells, particularly development of T-helper 17 (Th17) cells. Deregulation of this process leads to intestinal inflammation and tumorigenesis, via unknown mechanisms. TANK-binding kinase 1 (TBK1) is expressed by IECs and cells in the innate immune system. We studied the functions of TBK1 in the intestinal immune response and tumorigenesis in mice. METHODS: We performed studies of wild-type mice, mice with conditional disruption of Tbk1 (Tbk1IEC-KO), Tbk1IEC-KO mice crossed with ApcMin/+ mice, and Mt-/- mice crossed with ApcMin/+ mice. Some mice were given intraperitoneal injections of a neutralizing antibody against interleukin 17 (IL17) or IL1ß. Intestine tissues were collected from mice and analyzed by histology, for numbers of adenomas and Th17 cells, and expression of inflammatory cytokines by real-time PCR. IECs were isolated from wild-type and Tbk1IEC-KO mice, stimulated with lipopolysaccharide, co-cultured for with bone marrow-derived macrophages, and analyzed by RNA sequencing and biochemical analyses. RESULTS: Compared to ApcMin/+Tbk1WT mice, ApcMin/+Tbk1IEC-KO mice had significant increases in number and size of intestinal polyps, and significantly more Th17 cells in lamina propria. Administration of an antibody against IL17 reduced the number of intestinal polyps in ApcMin/+Tbk1IEC-KO mice to that observed in ApcMin/+Tbk1WT mice. In culture, TBK1-deficient IECs promoted expression of IL1ß by macrophages, which induced differentiation of naïve CD4+ T cells into Th17 cells. RNA sequencing analysis revealed that the TBK1-deficient IECs had increased expression of metallothionein 1 (MT1), an immune regulator that promotes intestinal inflammation. Intestine tissues from ApcMin/+Mt-/- mice had significant fewer Th17 cells than ApcMin/+Mt+/+ mice, and a significantly lower number of polyps. Analyses of colorectal tumors in the Cancer Genome Atlas found colorectal tumors with high levels of MT1 and IL17 mRNAs to be associated with reduced survival times of patients. CONCLUSIONS: Expression of TBK1 by IECs suppresses expression of MT1 and prevents expression of IL1ß by macrophages and differentiation of Th17 cells, to prevent inflammation and tumorigenesis. Strategies to block this pathway might be developed for colorectal tumorigenesis.

A Phase II Trial of Cytoreduction, Gastrectomy, and Hyperthermic Intraperitoneal Perfusion with Chemotherapy for Patients with Gastric Cancer and Carcinomatosis or Positive Cytology.

BACKGROUND: Current national guidelines do not include hyperthermic intraperitoneal chemoperfusion (HIPEC) as treatment for gastric cancer, and there are no completed clinical trials of cytoreduction, gastrectomy, and HIPEC from the US. METHODS: Patients with gastric adenocarcinoma and positive peritoneal cytology or carcinomatosis who had completed systemic chemotherapy and laparoscopic HIPEC underwent cytoreduction, gastrectomy, and HIPEC with 30 mg mitomycin C and 200 mg cisplatin. The primary endpoint was overall survival (OS), with a secondary endpoint of postoperative complications (NCT02891447). RESULTS: We enrolled 20 patients from September 2016 to March 2019. Six patients had positive cytology only and 14 had carcinomatosis. All patients were treated with systemic chemotherapy with a median of eight cycles (range 5-11 cycles) and at least one laparoscopic HIPEC. The median peritoneal carcinomatosis index at cytoreduction/gastrectomy/HIPEC was 2 (range 0-13). After surgery, the 90-day morbidity and mortality rates were 70% and 0%, respectively. Median length of hospital stay was 13 days (range 7-23 days); median follow-up was 33.5 months; median OS from the date of diagnosis of metastatic disease was 24.2 months; and median OS from the date of cytoreduction, gastrectomy, and HIPEC was 16.1 months. 1-, 2-, and 3-year OS rates from the diagnosis of metastatic disease were 90%, 50%, and 28%, respectively. CONCLUSIONS: Survival rates for patients with gastric adenocarcinoma and peritoneal disease treated with cytoreduction, gastrectomy, and HIPEC are encouraging; our early results are similar to those of recent prospective registry studies. Multi-institutional and cooperative group trials should be supported to confirm survival and safety outcomes.

Determinants of Survival for Patients with Neoadjuvant-Treated Node-Negative Gastric Cancer.

BACKGROUND: This study sought to determine prognostic markers for disease recurrence and survival in a cohort of neoadjuvant-treated, node-negative gastric cancer patients (ypT0-4N0M0). METHODS: Clinicopathologic data from patients treated with neoadjuvant therapy followed by curative-intent gastrectomy at the University of Texas MD Anderson Cancer Center from 1995 to 2017 were evaluated. Patients with AJCC TNM stage ypT0-4N0M0 were considered for analysis. RESULTS: The inclusion criteria were met by 212 patients with a mean age of 58.3 years. Of these patients, 60 % were male, 53 % were Caucasian, 87 % received chemoradiation, and 13 % received chemotherapy. The findings showed a median overall survival (OS) rate of 11.3 years, a 5-year survival rate of 72 %, and a 10-year survival rate of 57 %. During a median follow-up period of 5.5 years, 38.2 % of the patients died. In the multivariable analysis, ypT4-stage and nodal yield fewer than 16 were significantly associated with reduced OS. Cancer classified as ypT4 had more aggressive biologic traits, including lymphovascular and perineural invasion, and was treated more aggressively with total gastrectomy and additional organ resection despite frequent positive margins. Depth of invasion remained significantly associated with worse outcome after the analysis controlled for nodal yield and possible stage migration. Compared with ypT0-3 tumors, ypT4 cancers were associated with significantly more recurrences (13 % vs. 45 %; p < 0.05), and the primary modes of failure for ypT4 lesions were local recurrence and peritoneal metastases (88 % of recurrences). CONCLUSIONS: Depth of primary tumor invasion and nodal yield were significantly associated with OS among the patients with ypT0-4N0M0 gastric cancer. Serosal invasion (ypT4) was associated with a high rate of peritoneal recurrence, and trials of intraperitoneal therapy targeting these patients should be considered.

Influence of Baseline Positron Emission Tomography in Metastatic Gastroesophageal Cancer on Survival and Response to Therapy.

BACKGROUND: The value of baseline fluorodeoxyglucose-positron emission tomography-computed tomography (PET-CT) remains uncertain once gastroesophageal cancer is metastatic. We hypothesized that assessment of detailed PET-CT parameters (maximum standardized uptake value [SUVmax] and/or total lesion glycolysis [TLG]), and the extent of metastatic burden could aid prediction of probability of response or prognosticate. METHODS: We retrospectively analyzed treatment-naive patients with stage 4 gastroesophageal cancer (December 2002-August 2017) who had initial PET-CT for cancer staging at MD Anderson Cancer Center. SUVmax and TLG were compared with treatment outcomes for the full cohort and subgroups based on metastatic burden (≤2 or >2 metastatic sites). RESULTS: We identified 129 patients with metastatic gastroesophageal cancer who underwent PET-CT before first-line therapy. The median follow-up time was 61 months. The median overall survival (OS) was 18.5 months; the first progression-free survival (PFS) was 5.5 months. SUVmax or TLG of the primary tumor or of all metastases combined had no influence on OS or PFS, whether the number of metastases was ≤2 or >2. Overall response rates (ORRs) to first-line therapy were 48% and 45% for patients with ≤2 and >2 metastases, respectively (nonsignificant). ORR did not differ based on low or high values of SUVmax or TLG. CONCLUSIONS: This is the first assessment of a unique set of PET-CT data and its association with outcomes in metastatic gastroesophageal cancer. In our large cohort of patients, detailed analyses of PET-CT (by SUVmax and/or TLG) did not discriminate any parameters examined. Thus, baseline PET-CT in untreated metastatic gastroesophageal cancer patients has limited or no utility.

Navigating Nodal Metrics for Node-Positive Gastric Cancer in the United States: An NCDB-Based Study and Validation of AJCC Guidelines.

BACKGROUND: The optimal number of examined lymph nodes (ELNs) and the positive lymph node ratio (LNR) for potentially curable gastric cancer are not established. We sought to determine clinical benchmarks for these values using a large national database. METHODS: Demographic, clinicopathologic, and treatment-related data from patients treated using an R0, curative-intent gastrectomy registered in the National Cancer Database during 2004 to 2016 were evaluated. Patients with node-positive (pTxN+M0) disease were considered for analysis. RESULTS: A total of 22,018 patients met the inclusion criteria, with a median follow-up of 2.2 years. Mean age at diagnosis was 65.6 years, 66% were male, 68% were White, 33% of tumors were located near the gastroesophageal junction, and 29% of patients had undergone preoperative therapy. Most primary tumors (62%) were category pT3-4, 67% had a poor or anaplastic grade, and 19% had signet features. Clinical nodal staging was inaccurate compared with staging at final pathology. The mean [SD] number of nodes examined was 19 [11]. On multivariable analysis, the pN category, ELNs, and LNR were independently associated with survival (all P<.0001). Using receiver operating characteristic (ROC) analysis, an optimal ELN threshold of ≥30 was established for patients with pN3b disease and was applied to the entire cohort. Node positivity and LNR had minimal change beyond 30 examined nodes. Stage-specific LNR thresholds calculated by ROC analysis were 11% for pN1, 28% for pN2, 58% for pN3a, 64% for pN3b, 30% for total combined. By using an ELN threshold of ≥30, prognostically advantageous stage-specific LNR values could be determined for 96% of evaluated patients. CONCLUSIONS: Using a large national cancer registry, we determined that an ELN threshold of ≥30 allowed for prognostically advantageous LNRs to be achieved in 96% of patients. Therefore, ≥30 examined nodes should be considered a clinical benchmark for practice in the United States.

Concurrent lymphovascular and perineural invasion after preoperative therapy for gastric adenocarcinoma is associated with decreased survival.

BACKGROUND AND OBJECTIVES: We sought to evaluate the impact of lymphovascular invasion (LVI) and perineural invasion (PNI) on survival outcomes in gastric cancer patients treated with preoperative therapy. METHODS: Patients with gastric cancer treated with preoperative therapy and potentially curative resection were stratified according to the presence of LVI, PNI, or both. Kaplan-Meier and Cox regression analyses were used to evaluate the impact on overall survival (OS) and disease-free survival (DFS). RESULTS: The study included 281 patients, of whom 93 (33%) had LVI, 69 (25%) had PNI, 51 (18%) had both LVI and PNI, and 170 (61%) had neither. LVI and PNI were each associated with higher ypT and ypN categories and more positive lymph nodes (all p < .001), associations that were emphasized with both factors present. On multivariable analyses, ypN (p < .001) and concurrent LVI/PNI (hazard ratio [HR]: 2.62; 95% confidence interval [CI]: 1.55-4.45; p = .001) were predictive of OS and DFS (ypN: p < .001; both LVI/PNI: HR: 2.27; 95% CI: 1.34-3.82; p = .002). CONCLUSIONS: Gastric cancer patients with concurrent LVI and PNI after preoperative therapy have more advanced disease and worse survival outcomes than patients with neither or only one of these factors.

Multiplex profiling of peritoneal metastases from gastric adenocarcinoma identified novel targets and molecular subtypes that predict treatment response.

OBJECTIVE: Peritoneal carcinomatosis (PC) occurs frequently in patients with gastric adenocarcinoma (GAC) and confers a poor prognosis. Multiplex profiling of primary GACs has been insightful but the underpinnings of PC's development/progression remain largely unknown. We characterised exome/transcriptome/immune landscapes of PC cells from patients with GAC aiming to identify novel therapeutic targets. DESIGN: We performed whole-exome sequencing (WES) and whole transcriptome sequencing (RNA-seq) on 44 PC specimens (43 patients with PC) including an integrative analysis of WES, RNA-seq, immune profile, clinical and pathological phenotypes to dissect the molecular pathogenesis, identifying actionable targets and/or biomarkers and comparison with TCGA primary GACs. RESULTS: We identified distinct alterations in PC versus primary GACs, such as more frequent CDH1 and TAF1 mutations, 6q loss and chr19 gain. Alterations associated with aggressive PC phenotypes emerged with increased mutations in TP53, CDH1, TAF1 and KMT2C, higher level of 'clock-like' mutational signature, increase in whole-genome doublings, chromosomal instability (particularly, copy number losses), reprogrammed microenvironment, enriched cell cycle pathways, MYC activation and impaired immune response. Integrated analysis identified two main molecular subtypes: 'mesenchymal-like' and 'epithelial-like' with discriminating response to chemotherapy (31% vs 71%). Patients with the less responsive 'mesenchymal-like' subtype had high expression of immune checkpoint T-Cell Immunoglobulin And Mucin Domain-Containing Protein 3 (TIM-3), its ligand galectin-9, V-domain Ig suppressor of T cell activation (VISTA) and transforming growth factor-ß as potential therapeutic immune targets. CONCLUSIONS: We have uncovered the unique mutational landscape, copy number alteration and gene expression profile of PC cells and defined PC molecular subtypes, which correlated with PC therapy resistance/response. Novel targets and immune checkpoint proteins have been identified with a potential to be translated into clinics.

Phase I Trial of Hyperthermic Intraperitoneal Chemoperfusion (HIPEC) with Cisplatin, Mitomycin, and Paclitaxel in Patients with Gastric Adenocarcinoma and Associated Carcinomatosis or Positive Cytology.

BACKGROUND: The purpose of this phase I trial is to evaluate the safety and toxicity of laparoscopic hyperthermic intraperitoneal perfusion with chemotherapy (HIPEC), combining mitomycin, cisplatin, and paclitaxel for patients with gastric cancer metastatic to the peritoneum. PATIENTS AND METHODS: A Bayesian optimal interval design was used to prospectively identify the safety and tolerability of escalating doses of paclitaxel in combination with flat doses of mitomycin (30 mg) and cisplatin (200 mg) during laparoscopic HIPEC. The primary objective is to define the maximum tolerated dose. Secondary endpoints include surgical complications and overall survival (OS). RESULTS: A total of 27 patients were treated between 11/2017 and 11/2018. No dose-limiting toxicities were observed. Treatment-related grade 1-2 toxicities were leukopenia (11%), oral dysesthesia (4%), arthralgia (4%), and diarrhea (4%). Treatment-related grade 3-4 toxicities included leukopenia (4%) and neutropenia (4%). The maximum dose for paclitaxel was 60 mg/m2. Rates of Clavien-Dindo surgical complications were grade I 96% (all electrolyte deficiencies requiring replacement), II 4%, III 0%, IV 0%, and V 4%. The median follow-up time was 15 months. One- and 2-year OS rates from date of metastatic disease were 73.9% and 58.1%, respectively. CONCLUSIONS: Laparoscopic HIPEC with mitomycin, cisplatin, and paclitaxel may be safely used at intraperitoneal doses of 30 mg, 200 mg, and 60 mg/m2, respectively. Although electrolyte abnormalities were common, systemic toxicity was low. Survival rates were promising, supporting further research into intraperitoneal therapy for stage IV gastric cancer.

Impact of tumor regression grade on recurrence after preoperative chemoradiation and gastrectomy for gastric cancer.

BACKGROUND AND OBJECTIVES: It is unknown whether the degree of response to preoperative therapy correlates with locoregional recurrence (LR) or distant recurrence (DR) after resection of gastric cancer. METHODS: Patients who underwent resection of gastric adenocarcinoma following chemotherapy and chemoradiation (1995-2015) were reviewed. The tumor regression grade (TRG) was defined by the percentage of viable tumor cells in the specimen (TRG0 = 0%; TRG1 = 1%-2%; TRG2 = 3%-50%; TRG3 ≥ 50%). The relationships among TRG, recurrence-free survival (RFS), LR, and DR were examined. RESULTS: Two hundred forty-seven patients met the inclusion criteria (TRG0, 52 [21%]; TRG1, 49 [20%]; TRG2, 98 [40%]; TRG3, 48 [19%]). LR and DR occurred in 6.1% and 32.0% of patients, respectively. No patient with TRG0 experienced LR. R1 resection (6%-15%) and LR (6%-8%) rates were similar among TRG1-3 patients. R1 resection was associated with LR (hazard ratio [HR], 17.85; P < .001). ypN status (HR, 2.44; P = .004) and linitis plastica (HR, 2.90; P < .001) were associated with DR. TRG was not independently associated with RFS, LR, or DR. CONCLUSIONS: TRG0 imparted excellent local control. However, TRG1-3 patients had similar R1 resection rates and therefore similar LR. DR is associated with ypN status and linitis plastica, not TRG.

Low metabolic activity in primary gastric adenocarcinoma is associated with resistance to chemoradiation and the presence of signet ring cells.

PURPOSES: Preoperative chemoradiation is a potential treatment option for localized gastric adenocarcinoma (GAC). Currently, the response to chemoradiation cannot be predicted. We analyzed the pretreatment maximum standardized uptake value (SUVmax) and total lesion glycolysis (TLG) on positron emission tomography/computed tomography as potential predictors of the response to chemoradiation. METHODS: We analyzed the SUVmax and TLG data from 59 GAC patients who received preoperative chemoradiation. We used logistic regression models to predict a pathologic complete response (pCR) and Kaplan-Meier curves to determine overall survival among patients with high and low SUVmax or TLG. RESULTS: Twenty-nine patients (49%) had Siewert type III adenocarcinoma and 30 (51%) had tumors located in the lower stomach. Forty-one patients had poorly differentiated GAC, and 26 had signet ring cells. The median SUVmax was 7.3 (0-28.2) and the median TLG was 56.6 (0-1881.5). Patients with signet ring cells had a low pCR rate, as well as a low SUVmax and TLG. In the multivariable logistic regression model, high SUVmax was a predictor of pCR (odds ratio = 11.1, 95% confidence interval = 2.12-50.0, p = 0.004). Overall survival was not associated with the SUVmax (log-rank p = 0.69) or TLG (log-rank p = 0.85) CONCLUSION: A high SUVmax was associated with sensitivity to chemoradiation and pCR in GAC, and signet ring cells seemed to confer resistance.

Characteristics and Survival of Gastric Cancer Patients with Pathologic Complete Response to Preoperative Therapy.

BACKGROUND: Pathologic complete response of a primary tumor (ypT0) after preoperative therapy is associated with improved overall survival (OS). However, whether other variables are associated with outcome for gastric cancer patients with ypT0 status is unknown. METHODS: This study reviewed an institutional database of patients who underwent resection of gastric or gastroesophageal adenocarcinoma after preoperative therapy and identified patients with ypT0 status. Cox regression models were used to identify clinicopathologic predictors of OS. RESULTS: Of 77 patients with ypT0 status identified in this study, 36 (47%) had gastroesophageal junction tumors. At presentation, 62 patients (81%) had clinical T3 disease, and 7 (9%) had clinical T4 disease. The clinical nodal status was positive (cN+) for 45 patients (58%). Preoperative chemoradiation was administered to 75 patients (97%). The median follow-up duration was 3.54 years. The median OS was 10 years, and the 5-year OS rate was 61%. Univariable analysis identified age of 65 years or older at the time of diagnosis, histologic grade, and ypN status as significant predictors of OS. Multivariable analysis confirmed age of 65 years or older [hazard ratio (HR), 4.26; p < 0.001] and persistent nodal disease (ypN+ status; HR, 5.12; p < 0.001) to be independently associated with OS. Clinical stage was not associated with survival. In the subset of ypT0N0 patients, no clinicopathologic feature was predictive of survival. CONCLUSION: For gastric or gastroesophageal adenocarcinoma patients with ypT0 status after preoperative therapy, ypN+ status substantially reduced survival. Pretreatment clinical stage had no impact on OS for patients with a pathologic complete response.