Comparison of Clinical Efficacy of Neoadjuvant Chemoradiation Therapy Between Lower and Higher Radiation Doses for Carcinoma of the Esophagus and Gastroesophageal Junction: A Systematic Review

Abstract

<h3>Purpose</h3> Neoadjuvant concurrent chemoradiation therapy (nCRT) plus surgery has been a standard treatment for locoregionally advanced esophageal cancer and carcinoma of the gastroesophageal junction (EC/GEJ), but the optimal preoperative radiation dose is still unclear. We performed this systematic review to explore the treatment efficacy and toxicity of different radiation dose levels and find an optimal dose‐fractionation strategy in EC/GEJ patients receiving nCRT. <h3>Methods and Materials</h3> Embase and Ovid Medline were searched for articles involving cases of operable squamous and adenocarcinoma of the esophagus and GEJ in which patients received nCRT up to a dose of 50.4 Gy in 28 fractions that were published until July 2019, when the search was performed. Physical dose distributions were converted to biologically equivalent doses (BEDs), which were described in units of gray (alpha/beta). Pooled rates of overall survival (OS), progression-free survival (PFS), failure patterns, and toxicities were compared between lower-dose radiation therapy (LDRT; BED ≤48.85 Gy₁₀) and higher-dose radiation therapy (HDRT; BED >48.85 Gy₁₀) for patients treated with nCRT. <h3>Results</h3> A total of 110 studies with 7577 EC/GEJ patients receiving nCRT were included in this pooled analysis. Both the PFS and OS rates of patients receiving LDRT were significantly higher than those of patients receiving HDRT. Patients receiving LDRT had improved safety regarding treatment-related adverse events and lower distant failure rates than patients receiving HDRT. Utilization of modern radiation therapy (RT) techniques, including 3-dimensional conformal RT and intensity modulated RT, was associated with improved oncologic outcomes compared with 2-dimensional methods. Subgroup analysis showed that EC/GEJ patients receiving conventionally fractionated radiation to a dose of 40.0 to 41.4 Gy in 20-23 fractions showed improved OS compared with those receiving radiation above this dose. <h3>Conclusions</h3> Based on the limited data, nCRT using BED ≤48.85 Gy₁₀ was suitable for locoregionally advanced, resectable EC/GEJ. A total dose of 40.0 to 41.4 Gy in 20 to 23 fractions using modern RT techniques might provide the optimal therapeutic ratio.