The Children and Adolescents Nasopharyngeal Carcinoma Survivor Study

Overall survival(OS)

The OS was defined as the duration from the date of random assignment to the date of death from any cause or censored at the date of the last follow-up.

Progress-free survival(PFS)

Progress-free survival is calculated from the date of randomization to the date of the first progress at any site or death from any cause or censored at the date of the last follow-up

Locoregional failure-free survival(LRFS)

The LRFS is evaluated and calculated from the date of random assignment until the day of first locoregional relapse or until the date of the last follow-up visit

Distant metastasis-free survival(DMFS)

The DMFS is evaluated and calculated from the date of random assignment until the day of first distant metastases or until the date of the last follow-up visit

Short-term toxic effects assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.0)

The shortterm toxic effects were assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.0)

Long-term toxicities

QoL was assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTCQLQ-C30)

Long-term toxicities

EORTC quality of life questionnaire(QLQ) Head and Neck

Long-term toxicities

Late Effects Normal Tissue Task Force-Subjective, Objective, Management and Analytic (LENT-SOMA) scoring systems

Growth

Patients will be monitored for height(in metre)