Three-dimensional small-volume irradiation for residual or recurrent nasopharyngeal carcinoma

PURPOSE: To minimize side effects and to achieve a high local control rate, three-dimensional (3D) small-volume irradiation was used for locally residual or recurrent nasopharyngeal carcinoma. METHODS AND MATERIALS: Between July 1992 and March 1998, 18 tumors (12 residual and 6 local recurrent cases) were treated with 3D planned small-volume irradiation. The total dose (i.e., the dose of conventional radiotherapy plus that of the 3D irradiation) was 78.4 Gy (74.8-91.0 Gy) in its mean value for residual disease and 105.0 Gy (94.8-125 Gy) for recurrence. The mean value of the 90% isodose volume was 40.3 cc (8.0-94.0 cc). The mean follow-up period from the start of the boost or re-irradiation was 39 months. RESULTS: The 3-year local control rate of the 12 residual tumors was 70%. Of 9 T4 residual tumors, 7 were controlled at a follow-up period between 17 and 70 months (median of 42 months). Of 6 recurrent tumors treated with re-irradiation, 3 were controlled at a follow-up period between 7 and 28 months. In the case of booster therapy, trismus occurred in 1 patient with a total dose of 91 Gy. Among the patients receiving re-irradiation, a temporary ulceration of the nasopharyngeal mucosa developed in 1 patient with a total dose of 111 Gy. CONCLUSION: 3D small-volume irradiation was effective and safe in treating residual or recurrent nasopharyngeal carcinoma.