Checkpoint blockade in esophagogastric cancer

Conversion surgery of Stage IV gastric cancer with peritoneal dissemination after nivolumab

A 69-year-old man was clinically diagnosed as stage IV gastric cancer with peritoneal dissemination. We performed systemic chemotherapy consisting of S-1 plus oxaliplatin as a first line, and ramucirumab plus nab-paclitaxel as a second line. However, CT and EGD revealed growth of the primary tumor and the lymph nodes along the lesser curvature and adjacent to the cardia. In addition, CT revealed ascites in the rectovesical pouch. Therefore, treatment was switched to nivolumab. After 3 treatment courses, CT revealed shrinkage of lymph nodes and disappearance of ascites. After 12 courses of nivolumab, however, EGD revealed growth of the tumors in the stomach with minor hemorrhage, prompting the consideration of gastrectomy. At the time of laparotomy, the peritoneal dissemination had completely disappeared, and peritoneal cytology was negative. Therefore, total gastrectomy with D2 and paraaortic lymphadenectomy was performed, after 21 months following the initial diagnosis. To our knowledge, there are no previous reports that have demonstrated the disappearance of peritoneal dissemination and ascites in response to nivolumab, resulting in curative gastrectomy.

The Immune Subtypes and Landscape of Gastric Cancer and to Predict Based on the Whole-Slide Images Using Deep Learning

Background

Gastric cancer (GC) is a highly heterogeneous tumor with different responses to immunotherapy. Identifying immune subtypes and landscape of GC could improve immunotherapeutic strategies.

Methods

Based on the abundance of tumor-infiltrating immune cells in GC patients from The Cancer Genome Atlas, we used unsupervised consensus clustering algorithm to identify robust clusters of patients, and assessed their reproducibility in an independent cohort from Gene Expression Omnibus. We further confirmed the feasibility of our immune subtypes in five independent pan-cancer cohorts. Finally, functional enrichment analyses were provided, and a deep learning model studying the pathological images was constructed to identify the immune subtypes.

Results

We identified and validated three reproducible immune subtypes presented with diverse components of tumor-infiltrating immune cells, molecular features, and clinical characteristics. An immune-inflamed subtype 3, with better prognosis and the highest immune score, had the highest abundance of CD8+ T cells, CD4+ T–activated cells, follicular helper T cells, M1 macrophages, and NK cells among three subtypes. By contrast, an immune-excluded subtype 1, with the worst prognosis and the highest stromal score, demonstrated the highest infiltration of CD4+ T resting cells, regulatory T cells, B cells, and dendritic cells, while an immune-desert subtype 2, with an intermediate prognosis and the lowest immune score, demonstrated the highest infiltration of M2 macrophages and mast cells, and the lowest infiltration of M1 macrophages. Besides, higher proportion of EVB and MSI of TCGA molecular subtyping, over expression of CTLA4, PD1, PDL1, and TP53, and low expression of JAK1 were observed in immune subtype 3, which consisted with the results from Gene Set Enrichment Analysis. These subtypes may suggest different immunotherapy strategies. Finally, deep learning can predict the immune subtypes well.

Conclusion

This study offers a conceptual frame to better understand the tumor immune microenvironment of GC. Future work is required to estimate its reference value for the design of immune-related studies and immunotherapy selection.

Recurrent gastric cancer sustaining a partial response after the nivolumab discontinuation because of immune-related adverse events: a case report

Background

The prognosis of patients with recurrent gastric cancer is poor despite chemotherapy being clinically recommended as the first therapeutic strategy. Recent clinical trials have established the clinical utility of nivolumab in the third-line treatment of such patients. Immune-related adverse events (irAE) have been focused as a promising predictor for tumor response to nivolumab. This report aims to present a long-term survivor of recurrent gastric cancer who was followed up without any treatments after the nivolumab discontinuation because of irAE.

Case presentation

A 65-year-old male with stage III gastric cancer (cT4aN1M0) underwent surgery after neoadjuvant chemotherapy. Owing to the final pathological stage IIIB (ypT4bN1M0), the patient received adjuvant chemotherapy. Nevertheless, during adjuvant chemotherapy 1-year post-surgery, computed tomography (CT) revealed lymph node swelling in station no. 9. Thus, upon diagnosis with lymph node recurrence, the patient was treated with two courses of capecitabine + oxaliplatin and three courses of ramucirumab + paclitaxel as the first- and second-line regimens, respectively. Based on these regimens, the patient had a progressive disease to chemotherapy. Consequently, we administered nivolumab as the third-line regimen. After four courses of nivolumab, CT revealed a significant shrinkage of the metastatic lymph node, with a 45.6% reduction. We confirmed a partial response during 11 courses of nivolumab. Since the occurrence of grade 4 diabetes mellitus after 12 courses of nivolumab, the patient was followed up without any treatment after the nivolumab discontinuation. Currently, the patient remains a partial response for 15 months, since the nivolumab discontinuation and is alive for 31 months after disease recurrence.

Conclusions

Acute irAE during nivolumab chemotherapy could be one of the crucial clinical factors to predict tumor suppression in patients with advanced gastric cancer.

Conversion surgery for stage IV gastric cancer with a complete pathological response to nivolumab: a case report

Background

Patients with stage IV gastric cancer have a poor prognosis despite the recent development of multidisciplinary treatments that include chemotherapy. However, conversion surgery has emerged as a promising strategy to improve the prognosis in responders with unresectable gastric cancer after chemotherapy. Moreover, nivolumab is currently recommended as a third-line treatment in patients with unresectable advanced gastric cancer. However, there are few reports of conversion surgery after nivolumab in patients with stage IV gastric cancer.

Case presentation

A 68-year-old woman complaining of nausea was diagnosed with stage I gastric cancer (T2N0M0). Although we planned gastrectomy with lymphadenectomy, multiple liver metastases were detected during the surgery. After staging laparoscopy, we diagnosed this patient as having stage IV unresectable gastric cancer, and we administered chemotherapy and immunotherapy for 39 months (first-line regimen: 6 courses of S-1 plus oxaliplatin; second-line regimen: 6 courses of ramucirumab plus paclitaxel; and third-line regimen: 20 courses of nivolumab). Although the liver metastases completely disappeared after the second-line chemotherapy, lung metastases and a rapid enlargement of the primary tumor were confirmed. Consequently, the patient received nivolumab at a dose of 3 mg/kg intravenously every 2 weeks, then a dose of 240 mg/kg intravenously every 2 weeks from September 2018. After 20 courses of nivolumab, the primary tumor dramatically shrank and the lung metastases disappeared. The patient had a partial primary tumor response to nivolumab. Therefore, the patient underwent laparoscopic distal gastrectomy with D2 lymph node dissection. The macroscopic examination of the resected specimen showed an ulcer scar in the primary tumor site. The pathological examination demonstrated no residual tumors and no lymph node metastases, and the histological response of the primary tumor was categorized as grade 3. The postoperative course was uneventful, and the patient is receiving nivolumab to control potential liver and lung metastases.

Conclusions

Conversion surgery might help control tumor progression in responders after chemotherapy and immunotherapy.

Immune Checkpoint Inhibitors in Locally Advanced, Unresectable, and Metastatic Upper Gastrointestinal Malignancies

BACKGROUND

Upper gastrointestinal (UGI) malignancies including esophageal, gastroesophageal junction (GEJ), and gastric cancers have a poor prognosis in the metastatic setting. Treatment with cytotoxic chemotherapy remains the treatment of choice in the first-line setting with the addition of trastuzumab, a monoclonal antibody against HER-2, if the tumor is HER2-positive. Before the era of checkpoint inhibitors, there were only few treatment options after failure of the first-line systemic therapy.

METHODS

We extensively searched the English written literature for peer-reviewed manuscripts regarding the use of checkpoint inhibitors in advanced stage and metastatic UGI cancer. We also searched and reviewed ongoing clinical trials from Clinicaltrials.gov.

RESULTS

Checkpoint inhibition is a promising therapeutic option in UGI cancers, which have overexpression of PD-L1, high mutation burden, or microsatellite instability. Checkpoint inhibitors that are being investigated or are approved in advanced UGI malignancies include PD-1 antibodies, nivolumab and pembrolizumab, PD-L1 antibody, avelumab, and CTLA-4 inhibitors, ipilimumab and tremelimumab.

CONCLUSIONS

Based on recent and ongoing studies, eligible patients who have progressed beyond the first-line cytotoxic chemotherapy may benefit from immunotherapy. This review outlines the checkpoint inhibitors that are currently or previously being investigated for patients with metastatic UGI cancers.

Response Rate and Prognostic Impact of Salvage Chemotherapy after Nivolumab in Patients with Advanced Gastric Cancer

OBJECTIVE

Nivolumab is recommended as a third-line treatment in patients with unresectable advanced or recurrent gastric cancer. Although recent studies have demonstrated the prognostic impact of salvage chemotherapy after immune checkpoint inhibitors in several malignancies, its clinical significance remains unclear in patients with gastric cancer. This study aimed to investigate tumor response to subsequent chemotherapy after nivolumab in patients with advanced gastric cancer and assess the prognostic effect of salvage chemotherapy.

METHODS

We retrospectively enrolled 31 patients with unresectable advanced or recurrent gastric cancer receiving nivolumab.

RESULTS

Twenty-two and nine patients received nivolumab as third-line and fourth- to sixth-line treatments, respectively. The objective response rate (ORR) and disease control rate (DCR) to nivolumab were 20.0% (4/20) and 55.0% (11/20), respectively. Eleven patients received salvage chemotherapy after nivolumab. The ORR and DCR to salvage chemotherapy were 37.5% (3/8) and 75.0% (6/8), respectively. The median progression-free survival and overall survival following salvage chemotherapy were 285 and 360 days, respectively.

CONCLUSION

Our preliminary study indicates that nivolumab exposure may enhance subsequent chemosensitivity in patients with advanced gastric cancer.

Intratumoral Immune Response to Gastric Cancer Varies by Molecular and Histologic Subtype

Immune checkpoint inhibition is effective in a subset of patients with advanced gastric cancer. Genomic profiling has revealed the heterogeneity of gastric adenocarcinomas, but the immune microenvironment and predictors of immunotherapy response remain poorly understood. We aimed to better characterize the underlying immune response to gastric cancer. Retrospective review of a prospectively maintained institutional database was performed to identify patients who underwent curative intent resection of gastric adenocarcinoma from 2006 to 2016. Tumors were classified according to modified TCGA subtype: Epstein-Barr virus (EBV)-associated, microsatellite instability (MSI)-high, intestinal as a surrogate for chromosomal instability, diffuse as a surrogate for genomically stable. Tumor-infiltrating leukocytes were measured using immunohistochemistry. Forty-three patients were identified: 6 EBV, 11 MSI, 14 intestinal, 12 diffuse. The most prevalent tumor-infiltrating leukocytes were CD8 T lymphocytes and CD68 macrophages, comprising 15% and 13% of all tumor cells. EBV and MSI tumors were the most infiltrated, harboring 30% to 50% T cells and 20% macrophages. Intestinal tumors contained fewer T cells but disproportionately more macrophages. Diffuse tumors were the least infiltrated. Programmed cell death protein 1 was most frequently expressed in intestinal tumors, whereas 70% of EBV and MSI tumors expressed programmed death-ligand 1. We herein demonstrate a heterogenous immune response to gastric cancer, which varies by tumor subtype and has implications for future immunotherapy trials. Checkpoint inhibition is unlikely to be effective as single-agent therapy against intestinal and diffuse tumors lacking prominent T-cell infiltration or substantial programmed death-ligand 1 expression.

Genomics and Targeted Therapies in Gastroesophageal Adenocarcinoma

Gastroesophageal adenocarcinomas (GEA) are devastating diseases with stark global presence. Over the past 10 years, there have been minimal improvements in treatment approach despite numerous clinical trials. Here, we review recent progress toward understanding the molecular features of these cancers and the diagnostic and therapeutic challenges posed by their intrinsic genomic instability and heterogeneity. We highlight the potential of genomic heterogeneity to influence clinical trial outcomes for targeted therapies and emphasize the need for comprehensive molecular profiling to guide treatment selection and adapt treatment to resistance and genomic evolution. Revising our clinical approach to GEA by leveraging genomic advances will be integral to the success of current and future treatments, especially as novel targets become therapeutically tractable. SIGNIFICANCE: GEAs are deadly cancers with few treatment options. Characterization of the genomic landscape of these cancers has revealed considerable genetic diversity and spatial heterogeneity. Understanding these fundamental properties of GEA will be critical for overcoming barriers to the development of novel, more effective therapeutic strategies.