Chemoradiotherapy for esophageal squamous cell cancer.

Chemoradiotherapy has been clinically indicated for patients with resectable esophageal squamous cell carcinoma who refuse surgical resection and in locally advanced unresectable esophageal squamous cell carcinoma patients. Concurrent chemoradiotherapy prolongs survival than radiation therapy alone when given as definitive treatment. Therefore, chemoradiotherapy is recognized as the standard non-invasive treatment for patients with localized esophageal cancer who opt for non-surgical treatment. JCOG9906 showed promising outcomes for stage II/III ESCC patients. But there are some problems about chemoradiotherapy for esophageal squamous cell carcinoma. Late toxicities are sometimes lethal for patients who achieved complete response even after years. Salvage treatment for residual or recurrent disease is unestablished. Modified Radiation Therapy Oncology Group regimen at the dose of 50.4 Gy reduced late toxicities without reducing efficacy. Optimal timings and procedure of salvage surgery and endoscopic therapy is evaluated in JCOG0909. Strategy including salvage therapy after chemoradiotherapy should be considered at the time of starting the treatment. Targeted therapy has not shown adding effect for chemoradiotherapy for esophageal squamous cell carcinoma yet. New agents, such as immune checkpoint inhibitors, are expected to show synergistic effect with chemoradiotherapy for esophageal squamous cell carcinoma. Further investigation is needed.