Salvage treatment after definitive chemoradiotherapy for esophageal squamous cell carcinoma

Definitive chemoradiotherapy (dCRT) for the esophageal squamous cell carcinoma (ESCC) is performed for patients with cT4 disease without distant metastasis and also for those with cStage I-III who are unable to tolerate or who refuse surgery. The rates of clinical complete response (cCR) after dCRT differ depending on the cStage, and patients who once achieved cCR frequently experience tumor recurrence. For those with residual tumor or with recurrence, salvage treatment is performed to achieve a cure. Several procedures have been reported as salvage treatments. Salvage esophagectomy is associated with high rates of morbidity and mortality, but can offer long-term survival. With R0 resection, with cCR to dCRT, pulmonary complications appear to be important prognostic factors affecting overall survival (OS). Lymphadenectomy is performed for the patients with lymph node metastasis without recurrence of primary lesions or distant metastasis, but the contribution to long-term OS is unclear. Metastasectomy is performed when distant metastasis is limited to the lung and there are few lesions, possibly contributing to long-term OS. Endoscopic resection and photodynamic therapy are indicated for cT1a and cT1-2 residual or recurrent tumors, respectively, and can yield favorable outcomes. Re-CRT and re-radiotherapy are performed for the patients with contraindications for surgery, but neither appears to contribute to long-term OS despite high incidences of esophageal fistula and perforation.