Potential Molecular Targets in the Setting of Chemoradiation for Esophageal Malignancies

A Review of Advances in Radiotherapy in the Setting of Esophageal Cancers

Esophageal cancer is the eighth most common cancer worldwide and is the sixth most common cause of cancer-related mortality. The paradigm has shifted to include a multimodality approach with surgery, chemotherapy, targeted therapy (including immunotherapy), and radiation therapy. Advances in radiotherapy through techniques such as intensity modulated radiotherapy and proton beam therapy have allowed for the more dose homogeneity and improved organ sparing. In addition, recent studies of targeted therapies and predictive approaches in patients with locally advanced disease provide clinicians with new approaches to modify multimodality treatment to improve clinical outcomes.

Current landscape of radiation oncology in esophageal cancer: a narrative review

Background and Objective

Esophageal cancer is an aggressive disease that is the sixth leading cause of cancer-related death worldwide. The overall treatment paradigm for esophageal cancer has changed considerably over the past decade. This narrative review aims to summarize the current landscape of radiation oncology for esophageal cancer.

Methods

A systematic search of the MEDLINE/PubMed database and Clinicaltrials.gov was performed, focusing on studies published within the last 10 years. Our search queried "esophageal cancer [AND] neoadjuvant radiation" as well as "locally advanced esophageal cancer [AND] definitive radiation". Our search resulted in 298 total references. These were manually reviewed, and only 58 references were within our scope of interest ranging from 2012-2022.

Key Content and Findings

For resectable esophageal cancer, neoadjuvant chemoradiation followed by surgery has been defined as the standard of care over the past decade. In patients with incomplete response to neoadjuvant chemoradiation, the benefit of immunotherapy in the adjuvant setting has recently been established. Ongoing studies are examining whether perioperative chemotherapy may be equivalent to neoadjuvant chemoradiation in resectable esophageal adenocarcinoma. For locally advanced esophageal cancer, recent studies have failed to show a benefit with radiation dose escalation in an unselected population, although the use of early positron emission tomography (PET) response to guide dose escalation is currently being studied. Other ongoing studies aiming to improve outcomes in locally advanced esophageal cancer involve using proton beam therapy to reduce toxicity and combining immunotherapy or targeted therapies with chemoradiation to amplify response.

Conclusions

Recent advances in radiation oncology may continue to improve outcomes for patients with esophageal cancer.

Association of the programmed death ligand‐1 combined positive score in tumors and clinicopathological features in esophageal cancer

Background

The combined positive score (CPS) of the programmed death ligand‐1 (PD‐L1) 22C3 assay is a predictive marker of pembrolizumab monotherapy for advanced esophageal cancer (EC) patients. However, little is known about the association of the PD‐L1 22C3 CPS with the clinicopathological features and heterogeneity of PD‐L1 expression in EC in the Chinese population in a real‐world setting.

Methods

We examined the association of the PD‐L1 22C3 CPS with clinicopathological characteristics in 533 EC specimens. Further, we compared 37 cases' different blocks of the same specimen and 50 paired primary/metastatic lymph node lesions to investigate the heterogeneity of PD‐L1 expression.

Results

PD‐L1 positive expression was observed in 45.0% of 533 EC patients, including 46.8% with squamous cell carcinoma, 15.4% with adenocarcinoma, 28.6% with basaloid squamous carcinoma, 42.9% with spindle cell carcinoma, and 33.3% with neuroendocrine tumors. PD‐L1 positive expression was positively associated with lymph node metastasis (59.2% chance, p = 0.021) and venous/lymphatic invasion (66.3% chance, p = 0.029). PD‐L1 expression was highly consistent in different paraffin blocks of the same surgically resected specimen (concordance rate: 86.5%, p = 0.000016) and a moderate consistency (concordance rate: 78.0%, p = 0.000373) for the primary and metastatic lymph node lesion comparison.

Conclusions

This is a novel study which demonstrated a positive correlation between a high PD‐L1 22C3 CPS and invasion/metastasis risk in EC surgical specimens. Both paired blocks and paired primary/metastatic lymph node lesions showed significant concordance. PD‐L1 heterogeneity was inferred to be mainly related to positive mononuclear inflammatory cells (MICs), which might have substantial implications for clinical practice.