<qa>  How many patients will be randomized to detect an improvement of median survival?Patients with stage IVA T4 andor IVB N3 but without distant metastasis will be enrolled. A total of up to 480 patients will be randomized to detect an improvement of median overall survival from 5.8 to 8.7 years, with an a0.05 and power of 0.8 using a two-sided logrank test with one interim analysis. 