Principles of radiation therapy

Abstract

Radiation therapy is integral to the management for localized cancers of the esophagus and gastroesophageal junction. It is primarily used concurrently with chemotherapy prior to surgery as a component of trimodality therapy. For patients who are unable to tolerate this aggressive approach, primary chemoradiation is utilized. Randomized data has established a benefit to concurrent chemoradiation over radiation alone whether administered in the neoadjuvant setting or as primary management. In the palliative setting, radiation alone can provide symptom relief. The treatment design and delivery of radiation for esophageal cancer requires a comprehensive understanding of the natural history of the disease, patterns of failure, anatomy and principles of radiobiology. The use of pretreatment imaging has improved target delineation. Modern radiation techniques such as intensity-modulated radiation therapy (with 4-dimensional CT scans) and proton beam radiation are able to spare dose to critical structures such as heart and lung and limit overall treatment morbidity while delivering maximal cytotoxic doses to the primary tumor. The timing, sequence, and benefit of adding checkpoint inhibitors or other targeted agents to radiation therapy are currently under investigation.