[Prognostic factors in nasopharyngeal carcinoma in childhood and adolescence].

OBJECTIVE: To analyze the prognostic factors affecting long-term result in pediatric or adolescent nasopharyngeal carcinoma.
METHODS: From January 1984 to December 1998, 117 cases of pediatric and adolescent nasopharyngeal carcinoma proven by pathology were treated by radiotherapy and/or chemotherapy. Their data were retrospectively analyzed. Of the 117 patients, 35 received chemotherapy before radiotherapy, 36 were treated with continuous radiotherapy and the other 81 with split-course radiotherapy. A dose of 56 - 80 Gy/6 - 13 weeks (66.32 +/- 4.72 Gy) was given in the nasopharynx and 47 - 73 Gy/5 - 13 weeks (57.90 +/- 5.80 Gy) in the neck. The survival rates were assessed by Kaplan-Meier analysis and the survival curves compared by Log-rank test. The multivariate analysis was conducted by Cox model.
RESULTS: The 1-, 3- and 5-year overall survival rate was 86.3%, 66.6% and 56.4%, respectively; and disease-free survival rate at 1, 3 and 5 years was 71.8%, 53.9% and 50.4%, respectively. A monovariate analysis showed that the age (P = 0.0015), mode of biopsy (P = 0.0234), N stage (P = 0.0001), mode of irradiation (P = 0.0027), chemotherapy (P = 0.0056) and short-term result (P = 0.0000) were the significant prognostic factors. The multivariate analysis demonstrated that the age (P = 0.027), N stage (P = 0.048), mode of irradiation (P = 0.009) and short-term result (P = 0.000) were the factors influencing prognosis of nasopharyngeal carcinoma in childhood and adolescence. Radiation-induced brain injuries were observed in 17 patients including brain stem injury in 1 (0.9%), temporal brain lobes in 3 (2.6%) and cranial nerves in 13 (11.1%).
CONCLUSION: The mode of irradiation, N stage and short-term result are the significantly influencing factors of prognosis in pediatric and adolescent nasopharyngeal carcinoma. Radiation-induced brain injuries during radiotherapy should not be overlooked.