A Meta-Analysis and Review of Radiation Dose Escalation in Definitive Radiation Therapy between Squamous Cell Carcinoma and Adenocarcinoma of Esophageal Cancer.

Simple Summary: The standard treatment of choice for inoperable esophageal cancer is concurrent chemoradiation therapy. However, the treatment effect varies among patients. Currently, the optimal dose for esophageal cancer for different histologies is still under debate, and the guidelines still recommend using the same dose to treat both squamous cell carcinoma and adenocarcinoma despite their differences in radiation sensitivity. In this review article, we analyzed previous studies treating esophageal cancers with definitive radiotherapy, with or without concurrent chemotherapy. We found that squamous cell carcinoma shows an overall survival benefit with the use of radiation dose escalation, while no advantage was found for adenocarcinoma. Based on these findings, we suggest that further dose escalation can be performed for esophageal squamous cell carcinoma. Esophageal cancer, ranked as the eighth most prevalent cancer globally, is characterized by a low survival rate and poor prognosis. Concurrent chemoradiation therapy (CCRT) is the standard therapy in the non-surgical treatment of localized carcinoma of the esophagus. Nevertheless, the radiation doses employed in CCRT remain notably lower compared to the curative definite chemoradiation therapy utilized in the management of other carcinomas. In order to increase the local control rates and enhance the treatment outcomes, several clinical trials have used high-dose radiation to analyze the effect of dose escalation. Despite the integration of technically advanced RT schemes such as intensity-modulated radiation therapy (IMRT), the results of these trials have failed to demonstrate a significant improvement in overall survival or local progression-free survival. In this review, we investigated previous clinical trials to determine the ineffectiveness of radiation dose escalation in the context of CCRT for esophageal cancer. We aim to clarify the factors contributing to the limited efficacy of escalated radiation doses in improving patient outcomes. Furthermore, we delve into recent research endeavors, exploring prospective radiation dose modifications being altered based on the histological characteristics of the carcinoma. The exploration of these recent studies not only sheds light on potential refinements to the existing treatment protocols but also seeks to identify novel approaches that may pave the way for more efficacious and personalized therapeutic strategies for esophageal cancer management. [ABSTRACT FROM AUTHOR]