 Overall survival was calculated from the date of randomization to the date of death; disease free survival was calculated from the date of randomization to tumor recurrence or distant metastasis or death from any cause; locoregional recurrencedistant metastasis free survival was calculated from the date of randomization to locoregional recurrencedistant metastasis of tumor or death from any cause. Time to locoregional recurrencedistant metastasis was calculated from the date of finishing treatment to tumor locoregional recurrencedistant metastasis. Patients were monitored by every three months in the first two years, every six months in the next 2 years, and once a year thereafter until death or data censoring. 