Radiotherapy on neck for nasopharyngeal carcinoma patients with negative cervical lymph node]

Nasopharyngeal carcinoma (NPC) patients with negative cervical lymph node (N0-NPC) account for 20% -30% of all NPC patients. Prophylactic irradiation to the upper neck is a criterion of treatment for these patients. But some authors suggest to prophylactically irradiate the the whole neck. This study was to analyze and compare long-term outcomes of the N0-NPC patients treated by prophylactic irradiation to the upper neck and to the whole neck, and explore radiotherapy on neck for N0-NPC patients.A total of 178 N0-NPC patients, proved by pathology, were treated in our hospital from Jul. 1998 to Dec. 1999. Of the 178 patients, 88 received prophylactic irradiation to the upper neck (upper neck group), 90 received prophylactic irradiation to the whole neck (whole neck group). Kaplan-Meier method and log-rank test were used to analyze and compare survival rate of the 2 groups. Cox model was used to study prognostic factors of N0-NPC.The 1-, 3-, and 5-year overall survival rates were 98.9%, 90.9%, and 80.7% in upper neck group, and 97.8%, 80.0%, and 71.1% in whole neck group (P = 0.224). The 1-, 3-, and 5-year disease-free survival rates were 93.2%, 80.7%, and 77.3% in upper neck group, and 85.6%, 68.9%, and 64.4% in whole neck group (P = 0.163). The incidence of cervical lymph nodes recurrence was 1.14% in upper neck group, and 1.09% in whole neck group (P> 0.05). Multivariate analysis showed that gender, T stage, and short-term outcome were independent prognostic factors of N0-NPC.Prophylactic irradiation to upper neck is recommended for N0-NPC patients.