AIM: Tumor response and normal tissue toxicity of seven-day-per-week continuous accelerated irradiation (CAIR) for patients with esophageal carcinoma were evaluated and compared to conventional irradiation (CR). METHODS: Sixty patients with squamous cell carcinoma of the esophagus were randomized into two groups: the CAIR group (30 patients) and the CR group (30 pa- tients). Patients in the CAIR group received radiotherapy (RT) with 2 Gy/fraction per day at 7 d/wk with a total dose of 50-70 Gy (average dose 64.2 Gy). The overall time of irradiation was 3.6-5.0 wk (average 4.6 wk). RT in the CR group was 2 Gy/fraction per day at 5 d/wk with a total dose of 40-70 Gy (average dose 61.7 Gy). The overall time of irradiation was 4.0-7.0 wk (average 6.4 wk). RESULTS: The data showed that the immediate tumor response to RT was better in the CAIR group than in the CR group. Efficiency rates (CR plus PR) were 82.8% (24/29) and 58.6% (17/29), respectively (P = 0.047). In both groups the incidences of esophagitis and tracheitis were insignificant (P = 0.376, 0.959), and no patient re- ceived toxicity that could not be tolerated. CONCLUSION: CAIR shortens overall treatment time and is well tolerated by patients. It may be superior to CR in enhancing the local response of tumor, but its remote effect for esophageal carcinoma awaits further follow-up. AIM: Tumor response and normal tissue toxicity of seven-day-per-week continuous accelerated irradiation (CAIR) for patients with esophageal carcinoma were evaluated and conventional to radiation (CR). METHODS: Sixty patients with squamous cell carcinoma of the esophagus were Patients in the CAIR group received radiotherapy (RT) with 2 Gy / fraction per day at 7 d / wk with a total dose of 50-70 Gy average dose 64.2 Gy. The overall time of irradiation was 3.6-5.0 wk (average 4.6 wk). RT in the CR group was 2 Gy / fraction per day at 5 d / wk with a total dose of 40 -70 Gy (average dose 61.7 Gy). The overall time of irradiation was 4.0-7.0 wk (average 6.4 wk). RESULTS: The data showed that the immediate tumor response to RT was better in the CAIR group than in the CR group. In both groups the incidence (CR plus PR) were 82.8% (24/29) and 58.6% (17/29), respectively (P = 0.047). s of esophagitis and tracheitis were insignificant (P = 0.376, 0.959), and no patient re- ceived toxicity that could not be tolerated. CONCLUSION: CAIR shortens overall treatment time and is well tolerated by patients. It may be superior to CR in enhancing the local response of tumor, but its remote effect for esophageal carcinoma awaits further follow-up.