Involved Field Irradiation (IFI) Versus Elective Nodal Irradiation (ENI) for Esophageal Cancer

Involved Field Irradiation(IFI):only irradiate positive lymph node by CT or PET-CT Radiation: IMRT IMRT is administered with chemotherapy from week 1 to week 8PTV-GTV（primary tumor）：66-70Gy/33\~35F，once a day, 5 times per week PTV-CTV（Clinical target,primary tumor extended 3cm in Axial）：50-56Gy/33\~35f，once a day, 5 times per week PTV-GTVnd（positive node）：66-70Gy/33\~35F，once a day, 5 times per week.

Drug: docetaxel and cisplatin.Consists of docetaxel 60-80mg/m2 day 1 and cisplatin 25mg/m2 days 1 to 3, repeat every 3 weeks, for 2 cycles.

The CTVn of ENI included the involved lymph node regions and clinically uninvolved lymph nodal stations according to the location of primary tumor. Lymph node station numbers 1/2/4/5/7, 2/4/5/7 and 4/5/7/16/17were included for upper, middle and lower thoracic ESCC in the ENI arm respectively.