Role of immunotherapy in esophageal cancer and its impact on surgical outcomes: a narrative review

Tumor progression is often associated with immune suppression or the ability of the tumors to avoid immune surveillance. Immunotherapy improves the ability of the immune system to recognize and clear tumor cells with a little influence on the normal tissues. Immunotherapy is a hot spot in the research of advanced esophageal cancer. Immunotherapy of esophageal cancer includes immune checkpoint inhibitors, adoptive cellular immunotherapy, tumor vaccines and antibody therapy. At present, a large number of clinical trials are underway to evaluate the role of immunotherapy in esophageal cancer. Checkpoint inhibitors represented by Pembrolizumab and Nivolumab, has achieved initial success in the treatment of advanced esophageal cancer to improve the prognosis and life quality of esophageal cancer patients. In the future, further studies are needed to have a research on the effects of tumor heterogeneity, prediction of therapeutic targets, and immune tolerance. Key words: Esophageal neoplasms; Immunotherapy; Immune checkpoint blockades

Esophageal cancer has witnessed a significant shift in its epidemiology within the United States. Adenocarcinoma of the esophagus is now the fastest-growing solid malignancy, surpassing esophageal squamous cell carcinoma (ESCC) in frequency. There has been a concentrated effort to establish new therapies for dealing with this malignancy including immunotherapy in conjunction with surgery and radiotherapy. Our objective is to provide a comprehensive review of the current therapeutic strategies for esophageal cancer, with a particular focus on the emerging role of immunotherapy in combination with surgery and radiotherapy, and its impact on treatment outcomes. A thorough search was done using keywords of "esophageal cancer", "immunotherapy in esophageal cancer", and "immunotherapy" in PubMed, MEDLINE, and Google Scholar databases. All studies that were identified in this search were analyzed for relevance and content. A total of 1,555 studies were identified which were checked for relevance and content. Fifteen articles were reviewed which focused on esophageal cancer and the immunotherapy directed towards this condition. This review article summarizes the most recent and available evidence on immunotherapy directed towards the treatment of esophageal cancer. Esophageal cancer treatment is undergoing a paradigm shift with the advent of immunotherapy, particularly programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors. These therapies hold promise for both second-line and first-line settings, with evolving biomarkers guiding treatment decisions. Combination strategies and personalized approaches are actively investigated to overcome resistance mechanisms and enhance treatment outcomes in this challenging cancer type.

Targeting of the immune checkpoints cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed death (PD)-1/PD-ligand 1 (PD-L1) with monoclonal antibodies has been shown to improve outcomes in a number of solid tumors, leading to their routine use in clinical practice. Early phase evaluation of immune checkpoint inhibitors demonstrated encouraging results in esophageal cancer, and studies in the chemorefractory setting have confirmed the activity of immunotherapy in esophageal cancer. Immunotherapeutic strategies continue to be evaluated rapidly in esophageal cancer, in both the locally advanced and metastatic settings. This chapter will focus on the accumulating data regarding the use of immunotherapy in esophageal cancer.

Considering the benefits of immunotherapy in advanced melanoma, non–small cell lung cancer, renal cell carcinoma, bladder cancers, and refractory Hodgkin lymphoma, we begin to consider whether immunotherapy is effective for esophageal cancer, which is extremely malignant and has a poor prognosis. There are a large number of clinical trials to study the application of immunotherapy such as immune checkpoint inhibitors, peptide vaccine, adoptive T cell transfer and oncolytic virus in esophageal cancer. Some already have preliminary results and show the advantages of immunotherapy in esophageal cancer, while others are still in progress. This review aims to introduce the feasibility and current status of immunotherapy in esophageal cancer.

The current National Comprehensive Cancer Network advises neoadjuvant chemoradiotherapy followed by surgery for locally advanced cases of esophageal cancer. The role of immunotherapy in this context is under heavy investigation. Patients with esophageal adenocarcinoma were identified in the National Cancer Database (NCDB) from 2004 to 2019. Three groups were generated as follows: (a) no immunotherapy, (b) neoadjuvant immunotherapy, and (c) adjuvant immunotherapy. Overall survival was evaluated using the Kaplan-Meier method and Cox proportional hazard analysis, adjusting for previously described risk factors for mortality. Of the total 14,244 patients diagnosed with esophageal adenocarcinoma who received neoadjuvant chemoradiation, 14,065 patients did not receive immunotherapy, 110 received neoadjuvant immunotherapy, and 69 received adjuvant immunotherapy. When adjusting for established risk factors, adjuvant immunotherapy was associated with significantly improved survival compared to no immunotherapy and neoadjuvant immunotherapy during a median follow-up period of 35.2 months. No difference was noted among patients who received no immunotherapy vs. neoadjuvant immunotherapy in the same model. In this retrospective analysis of the NCDB, receiving adjuvant immunotherapy offered a significant survival advantage compared to no immunotherapy and neoadjuvant immunotherapy in the treatment of esophageal adenocarcinoma. The addition of neoadjuvant immunotherapy to patients treated with neoadjuvant chemoradiation did not improve survival in this cohort. Further studies are warranted to investigate the long-term outcomes of immunotherapy in esophageal cancer.

Esophageal cancer is considered one of the most significant challenges to public health worldwide. While various therapeutic options exist for esophageal cancer, including chemotherapy, radiotherapy, and surgery, several adverse effects of these medications have been reported. Therefore, a new generation of therapeutic lines should be applied to minimize complications. In this regard, immunotherapy is a novel approach that aims to kill tumor cells directly by targeting them. Specifically, monoclonal antibodies can target specific markers of esophageal cancer tumor cells, keeping other normal cells safe. Multiple monoclonal antibodies optimized for esophageal cancer, such as pembrolizumab, ramucirumab, trastuzumab, nivolumab, and ipilimumab, are available. On the other hand, esophageal cancer tumor cells express a specific inhibitory ligand and its receptor called programmed cell death, which can suppress T cell immune responses. This receptor provides an inhibitory signal, causing the highest expression of the PD-L1 ligand on tumor cells. The outcomes of this interaction lead to the suppression of the activation and function of T lymphocytes. Therefore, immunotherapy for esophageal cancer targeting the PD-1/PD-L1 pathway has shown a remarkable correlation with cancer care. This study presents a comprehensive review of the latest findings related to immunotherapy in esophageal cancer.

BackgroundThere is an ongoing debate on whether sex affects immune-suppressive tumor microenvironment and immunotherapy. Here, we explored the underlying molecular bases for sex dimorphisms and their impact on the efficacy of immunotherapy in esophageal cancer (EC).Methods2360 EC patients from phase 3 trials were pooled to compare overall survivals by calculating hazard ratios (HRs) and their 95% confidence intervals (CIs). Genomic data of 1425 samples were integrated to depict the genomic landscapes and antigenic features. We also examined the sex disparities based on single-cell RNA sequencing and T cell receptor-sequencing data from 105,145 immune cells in 60 patients.ResultsImmunotherapy was associated with favorable outcomes in men (HR, 0.71; 95% CI, 0.65–0.79; P < 0.001), but not in women (HR, 0.98; 95% CI, 0.78–1.23; P = 0.84) (Pinteraction =0.02). The frequencies of 8 gene mutations, 12 single base substitutions signatures, and 131 reactome pathways were significantly different between male and female. Additionally, six subtypes of HLA-II antigens were enriched in women. Hence, we constructed and then validated a sex-related signature to better predict the outcomes of immunotherapy. Exhausted CD8+ T cells were highly infiltrated in men, while naïve CD8+ T cells were more common in women. Further examinations on multiple malignancies suggested exhausted CD8+ T cells were enriched in patients who responded to immunotherapy.ConclusionsOur study delineated the robust genomic and cellular sex disparities in EC. Furthermore, male, rather than female, derived significantly benefits from immunotherapy. These results have implications for treatment decision-making and developing immunotherapy for personalized care.Plain English SummaryIn the past several years, immunotherapy has gradually replaced the traditional chemotherapy as the standard treatment in esophageal cancer. It is well-established that immunological responses in male and female differ significantly. However, there is an ongoing debate on whether sex can impact the treatment outcomes in immunotherapy. In the present study, we systematically characterized the genomic and cellular landscapes of esophageal cancer, and revealed the significant differences between male and female patients. Furthermore, with over 2000 patients with esophageal cancer, we showed that only men can benefit from immunotherapy. In women, immunotherapy failed to show superior over chemotherapy. These results have implications for treatment decision-making and developing next-generation immunotherapy for personalized care.

Background: Esophageal cancer remains a lethal malignancy accounting for 604,000 new cases and 544,000 cancer-related modalities worldwide. To date, the clinical outcomes for patient with esophageal cancer are severely limited by the lack of effective treatment modalities. Moreover, the intrinsic and acquired resistances to chemotherapy and radiotherapy, stemming from DNA damage responses, inevitably exacerbates the disease progression. Pyroptosis is a proinflammatory programmed cell death (PCD) that is causally linked to anti-tumor immune responses, but the development of pyroptosis-based therapy has been limited by the lack of effective inducers to mediate pyroptotic cell death in a tumor-specific and controllable manner. Herein, we establishes that near-infrared light-triggered tumor pyroptosis (NIR-pyroptosis) is a novel non-apoptotic anticancer modality, providing a promising opportunity to overcome apoptosis resistance in current esophageal cancer therapies. Method: In this study, a novel esophageal cancer-targeted, NIR-pyroptosis antibody-drug conjugates (ADC) was established by covalently conjugating IRDye700, a photosensitizer, with ICAM1 antibody using thiol-maleimide click chemistry. This antibody-photosensitizer conjugate (ICAM1-IRDye700) functions as a potent NIR-pyroptosis inducer in multiple preclinical models of esophageal squamous cell carcinoma (ESCC). The in vitro potency of ICAM1-IRDye700 was determined by flow cytometry, immunofluorescent co-localization, and high-content imaging. Transmission electron microscopy (TEM) further characterized pyroptosis-related morphological changes in ICAM1-IRDye700-treated ESCC cells. To elucidate its underlying mechanism, transcriptomic and immune-blot analyses were performed to identify the molecular signaling cascades of NIR-pyroptosis ignited by ICAM1-IRDye700. Results: Under minimal doses (2ug/ml) of near-infrared light stimulation, ICAM1-IRDye700 rapidly triggered pyroptosis in ESCC cells, achieving approximately 95% cell death within 2 hours. Importantly, the potency of NIR-pyroptosis predominantly depends on the spatio. At different stages of drug accumulation on the cell membrane, in endosomes, and lysosomes, the time of pyroptosis induction varied. Transmission electron microscopy further observed pyroptosis-related morphological changes, and immunoblot analysis and sequencing results also provided supporting evidence, demonstrating the activation of the subcellular depositing locations of ICAM1-IRDye700 upon NIR irradiation. Further biomechanistic studies reveal that ICAM1-IRDye700 potently activates NLRP1-CASP1-GSDMD signaling axis, leading to a boosted antitumor immunity in vivo. This antitumor immunity activation was independent from reactive oxygen species (ROS). Furthermore, NIR-pyroptosis works in synergy with PD-1 immunotherapy by improving adaptive antitumor immunity in immunocompetent tumor models. Conclusion: Collectively, we established ICAM1-IRDye700 as a concept-of-proof ADC for NIR-pyroptosis therapy. Mechanistically, we explored the biomechanism of how ICAM1-IRDye700 igniting NIR-pyroptosis in ESCC tumors. This novel ADC boosts innate and adaptive immunity, resulting in potent and sustained tumor attenuations in combination with PD-1 checkpoint immunotherapy. Citation Format: Xue-Fei Tian, Fan Chen, Xi-Ru Xue, Yang Yang, Peng Guo. Near-infrared light-triggered tumor pyroptosis potentiates PD-1 immunotherapy in esophageal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB083.

Although Barrett’s esophagus is the primary precursor of esophageal adenocarcinoma, the annual incidence of adenocarcinoma is 0.12% in a Barrett’s esophagus population. We hypothesized that the esophageal microbiome may be associated with mucosal immunity changes that may determine subsequent carcinogenesis. To better understand the association among the local microbiota composition, immune response and progression of esophageal cancer, we performed whole genome sequencing (WGS) and bulk RNASeq in parallel, from endoscopic biopsies (n=23) collected from patients with normal squamous cell (n=9), non-dysplastic Barrett’s esophagus (n=8) and esophageal adenocarcinoma (n = 6). Using a novel customized computational pipeline to identify and characterize bacteria from low microbial content endoscopic samples (Zhang et al, Genome Biology, 2015). WGS analysis revealed a higher microbial diversity in normal squamous cell carcinomas compared to the non-dysplastic Barrett’s esophagus with high abundance of Veilonella Parvula, Prevotella melaninogenica and Streptococcus parasanguinis. Unsupervised clustering analysis of the entire data set revealed high abundance of Fusobacterium nucleatum in adenocarcinoma samples, which has been associated with a shorter survival in esophageal cancer. To characterize the immune infiltration in the mucosal biopsy samples, we defined a 784-gene immune panel. Unsupervised clustering analysis of gene expression revealed a much higher immune infiltration in most adenocarcinoma and some non-dysplastic Barrett’s compared with normal esophageal squamous tissue samples. Especially CD4+ Th1 and Th2 helper cell as well as CD8+ T cell associated immune response are highly enriched in some adenocarcinoma and non-dysplastic Barrett’s esophageal samples. To further investigate the effect of immune tumor microenvironment on efficacy of immunotherapy, we performed single cell sequencing on matching normal and tumor tissues collected at baseline and post-treatment from 6 patients subjected to anti-PD1 therapy. Using this approach, we can identify both innate and adaptive immune cells in both pre and post treatment biopsies. We specifically observe upregulation of MHCII associated cells in post-treatment biopsies. Together, our data suggest that esophageal cancers display distinct microbial patterns associated with chronic inflammation and a tumor-promoting pro-inflammatory microenvironment. Note: This abstract was not presented at the meeting. Citation Format: Chao Zhang, Prashant V. Thakkar, Prateek Sharma, Sreekar Vennelaganti, Doron Betel, Manish A. Shah. Understanding associations among local microbiome, immune response, and efficacy of immunotherapy in esophageal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2826.

ABSTRACTIntroduction: Esophageal cancer (EC) is the eighth most common cancer in the world, and the prognosis of EC is still poor. Although immunotherapy has been developed in melanoma and lung cancer, it is also expected to show efficacy in EC. Currently, several clinical trials are ongoing to evaluate the safety and efficacy of immunotherapies, immune checkpoint inhibitors, adoptive T cell transfer, and therapeutic cancer vaccines in EC.Areas covered: This review provides an overview and the status of immunotherapy in EC. Clinical significance of molecules related immune checkpoints, especially PD-1 and PD-L1 is presented and the designs, results and future directions of clinical trials using immunotherapy in EC are provided.Expert opinion: To bring immunotherapy to the forefront of treatment for EC, it is necessary to select patients who can obtain a high efficacy of immunotherapy and to also elucidate the correct timing for administration. Moreover, combination therapies of immunotherapy with existing chemotherapy or radiation or other immunotherapy with different mechanisms of action must be evaluated to achieve excellent outcomes in patients with EC.

We examined the utility of serial liquid biopsies to monitor clonal dynamics and predict pathologic response in patients with esophageal/gastroesophageal junction (E/GEJ) cancer undergoing treatment with neoadjuvant immunotherapy and concurrent chemoradiation (CA209-906; NCT03044613). Methods: Using Targeted Error Correction sequencing (TEC-Seq), we performed high-depth next generation sequencing on 79 serial plasma samples from 16 patients with operable stage II/III E/GEJ cancer undergoing treatment with neoadjuvant nivolumab, followed by nivolumab plus chemo-radiation and surgery as part of the CA209-906 trial. Liquid biopsies were evaluated pre-treatment, after each of two cycles of neoadjuvant nivolumab, and after concurrent nivolumab and chemoradiation immediately prior to surgery, for an average of 4 time points per patient. Deep sequencing of matched leukocyte DNA and whole exome sequencing (WES) of pre-treatment tumors was performed. The origin of plasma variants was determined by comparison to tumor WES (tumor-derived) and leukocyte TEC-Seq (clonal hematopoiesis (CH)-derived or germline) and their clonal dynamics over time were evaluated. Resected tumors were reviewed by central pathology and percent residual tumor was estimated. Patients were followed for an average of 2 years post-surgery. Results: Eight of 16 patients had detectable circulating tumor-derived DNA (ctDNA) at any time point. Additionally, 13 CH-derived mutations were detected in plasma of 8 patients. The number of CH-derived mutations was correlated with increasing patient age. Identification and removal of CH-derived mutations via comparison to matched leukocyte sequencing allowed for accurate assessment of kinetics of bona fide tumor-derived mutations in plasma. Tumor mutation burden as determined by tumor WES was not associated with pathological response (mean baseline mutations per exome 90 vs 81 for patients with residual disease &amp;gt;20% and &amp;lt;20% respectively). Detectable ctDNA at the last pre-surgery time point was found in 3 patients and was associated with residual tumor &amp;gt;20% (50% vs 23% with or without detectable ctDNA respectively). ctDNA clearance, defined as detectable ctDNA at one or more earlier time points that subsequently becomes undetectable before surgery, occurred in 5 patients and was associated with improved pathologic response (80% of patients with ctDNA clearance had residual tumor &amp;lt;=20% and no evidence of disease progression). Furthermore, of the three patients who did not have ctDNA clearance, two subsequently developed disease progression. Conclusion: Comprehensive analyses of ctDNA from E/GEJ patients undergoing neoadjuvant immunotherapy with concurrent chemoradiation revealed ctDNA dynamics that were associated with pathologic response and disease recurrence. These approaches may be used to identify patients at high risk for disease progression. Citation Format: Jenna VanLiere Canzoniero, Vincent Lam, Zineb Belcaid, Mara Lanis, Lamia Rhymee, Blair Landon, Archana Balan, Kristen Marrone, Patrick Forde, Benjamin Levy, David Ettinger, Heather Schneider, Hanika Rodavia, Richard Battafarano, Stephen Yang, Stephen Broderick, Jinny Ha, Blair Jobe, Ali Zaidi, Elizabeth Thompson, Julie Brahmer, Victor Velculescu, Ronan Kelly, Josephine Feliciano, Valsamo Anagnostou. Liquid biopsy approaches for determining pathologic response to neoadjuvant immunotherapy in esophageal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 538.

Esophageal cancer continues to remain a global problem. The majority of patients with advanced and/or metastatic disease will have limited survival, which has essentially remained unchanged over the past 20 years. The dawn of the immunotherapy resurgence has brought hope in the lives of many patients with lung cancer and other solid tumors. The emerging data for esophageal cancer also indicates benefit in selected patients. We summarize the current data available in this review.

Purpose: This review summarizes the latest evidence on immunotherapy in esophageal cancer, with emphasis on histologic and molecular subtype differences, advances in immune checkpoint inhibitor (ICI)-based strategies, and future directions for optimizing therapy.Current Concepts: Histologic subtypes display distinct geographic patterns: esophageal squamous cell carcinoma (ESCC) predominates in East Asia, whereas adenocarcinoma is more common in Western countries. These subtypes differ in etiology, molecular characteristics, and the tumor immune microenvironment. Chronic carcinogen exposure confers high immunogenicity, characterized by increased tumor mutational burden and immune infiltration, which provides a strong rationale for immunotherapy. Programmed cell death-1–based chemo-immunotherapy is now established as the standard first-line treatment in advanced ESCC, demonstrating survival benefits in multiple phase III trials. ICIs are also being evaluated in perioperative settings and in combination with chemoradiotherapy, targeted agents, anti-angiogenic therapies, dual-checkpoint blockade, and bispecific antibodies. In the neoadjuvant setting, ICI combinations may yield favorable pathological complete response rates, and adjuvant nivolumab after chemoradiotherapy has improved disease-free survival in patients with residual disease.Discussion and Conclusion: The incorporation of ICIs across disease stages is rapidly transforming the management of esophageal cancer. Precision strategies, including active surveillance after a clinical complete response and detection of minimal residual disease using circulating tumor DNA, are emerging to guide treatment intensity. Priorities for future work include standardized predictive biomarkers, dynamic monitoring using liquid biopsy, and strengthened multidisciplinary collaboration to individualize care. Broad participation in clinical trials will be essential to further improve survival and quality of life for patients with esophageal cancer.

The treatment of esophageal cancer is difficult in clinic. Recently, the development of immune checkpoint inhibitors has brought the immunotherapies to a new age. In predicting the curative effect of biomarkers, programmed cell death-ligand 1, tumor mutation burden and microsatellite instability could promi-singly predict the effect of the immune checkpoint inhibitors. Various immune checkpoint inhibitors are emerging and the combination of immunotherapy have shown a great applied potential in a series of clinical trials of esophageal cancer. Key words: Esophageal neoplasms; Immunotherapy

BackgroundEsophageal cancer is a highly malignant cancer with a very poor prognosis. For resectable esophageal cancer, neoadjuvant treatment could improve the prognosis of esophageal cancer. However, current clinical neoadjuvant treatment options for esophageal cancer are still limited. The application of immunotherapy is a potentially beneficial new neoadjuvant treatment option for esophageal cancer. The objective of this meta-analysis is to evaluate the efficacy and safety of immunotherapy for the neoadjuvant treatment of esophageal cancer.MethodsWe will search Wanfang Database, SinoMed, China National Knowledge Infrastructure, Embase, Web of Science, Pubmed, and Cochrane Library for relevant articles published before July, 2021. We will also search the unpublished clinical trials of neoadjuvant immunotherapy in esophageal cancer in preprint website (such as bioRXiv and medRxiv) up to July, 2021. We will perform a meta-analysis to evaluate the efficacy and safety of neoadjuvant immunotherapy for resectable esophageal cancer. Randomized controlled trials (RCTs) will be included in this study. The risk of bias will be evaluated for each included study using the Cochrane Handbook for Systematic Reviews of Interventions. We will use RevMan 5.3 software for statistical analysis of the data.ResultsThe results of this study will provide evidence of immunotherapy using as neoadjuvant treatment for esophageal cancer. This meta-analysis will be submitted to a peer-reviewed journal seeking for publication.ConclusionThe results of this study will provide a reliable basis for clinicians and patients to formulate the best pre-surgical treatment plan for resectable esophageal cancer.Systematic review registrationINPLASY202120026.