[Long-term efficacy of external radiotherapy plus intracavitary hyperfractionated brachytherapy on nasopharyngeal carcinoma].

ABSTRACT

BACKGROUND & OBJECTIVE: Intracavitary hyperfractionated brachytherapy is one of the main methods in brachytherapy for early stage nasopharyngeal carcinoma (NPC). We developed the parapharyngeal space interstitial brachytherapy for the NPC patients with residual tumor in the parapharyngeal space after external radiotherapy, and used hyperfractionated brachytherapy as a boosting radiation for the locally advanced patients who have no tumor invasion in the base of skull. This study was to analyze the long-term efficacy of external radiotherapy plus intracavitary hyperfractionated brachytherapy on NPC, and explore the clinical value and suitable dose. METHODS: From Jan. 1998 to Dec. 2002, 352 NPC patients were treated by external radiotherapy plus intracavitary hyperfractionated brachytherapy in Fujian Provincial Tumor Hospital. The parapharyngeal space interstitial brachytherapy was used in the patients with residual tumor in the parapharyngeal space after external radiotherapy. The external irradiation dose varied from 50 to 70 Gy. Brachytherapy was delivered by 2.5-3.0 Gy per fraction, and 2 fractions per day with an interval of 6 h; the total dose ranged from 5 to 32 Gy with a median of 17 Gy. RESULTS: The overall 1-, 2-, 3-, and 5-year disease-free survival rates were 97.0%, 91.3%, 87.6%, and 84.7%, respectively. The 5-year survival rate was significantly higher in stage I-II patients than in stage III-IV patients (88.2% vs. 79.2%, P=0.016)û but the local control rate was similar in the 2 groups (94.1% vs. 91.7%). Thirty-two (9.4%) patients had radiation injury at the lower cranial nerve. CONCLUSION: External radiotherapy plus intracavitary and interstitial hyperfractionated brachytherapy can improve local control rate and survival rate of NPC, but the occurrence rate of radiation injury at the lower cranial nerve is higher in the patients with parapharyngeal space involvement than in other patients.