The role of brachytherapy in treatment of stage I esophageal cancer: A systematic review

PURPOSE: Despite advancements in the early detection of esophageal cancer, optimal radiotherapy methods for treatment of early disease have not yet been determined. Moreover, the benefit of intraluminal brachytherapy on local control or survival remains controversial. We performed a systematic review to establish the role of brachytherapy as boost therapy in stage I esophageal squamous cell carcinoma, and to evaluate associated survival outcomes. METHODS AND MATERIALS: A systematic search of three bibliographic databases from January 1950 to January 2019 was conducted. All studies investigating brachytherapy for curative intent were included and palliative treatment was excluded. Primary outcomes included overall survival and disease-free survival (DFS). Secondary outcomes included loco-regional control (LRC) and toxicity grades and/or complications. Two reviewers independently abstracted data and evaluated study quality using grading of recommendations assessment, development, and evaluation, pooled results were presented through risk ratios. RESULTS: A total of 12 retrospective studies met inclusion criteria. The overall quality of evidence yielded a Grade 1C rating (strong recommendation, low quality evidence). Of 525 included patients, 325 patients received both external beam radiation (EBRT), and brachytherapy, 132 underwent EBRT only, and 68 received brachytherapy with and/or without chemoradiation. For patient group treated with EBRT and brachytherapy, 5-year mortality, DFS and LRC were: 43% (27-59%), 63% (49-76%) and 72% (63-80%) respectively. Rates of complications reported included 82.1% Grade 1 esophagitis for a combined external beam radiation and brachytherapy cohort, 12.3% ulcerations, and 3.3% fistulae. CONCLUSIONS: Brachytherapy as a combined modality is encouraging, given its relative safety and effectiveness. Further prospective analysis using higher quality evidence is warranted to evaluate oncologic outcomes and survival advantage.