Stereotactic Radiotherapy Boost on Improvement of Local Control and Survival of Nasopharyngeal Carcinoma

Objective 　To evaluate the value of fractionated stereotatic radiation therapy (FSRT) (X knife) after intensity modulated radiotherapy ( IMRT) for residual nasopharyngeal carcirmma. (NPC) . Methods Thirty-one consecutive patient s were treated with stereotactic radiotherapy af ter IMRT for residual nasopharyngeal carcinoma f rom February 2004 to October 2006. The median FSRT dose was 16 Gy (12 ～20 Gy) . Prescribed at 1～3 centers on the 70 %～90 % isodose curves normalized to isocenter by multifractions of f raction size 4 Gy with interfraction duration of 1～3 days. Results 　The local cont rol rate in 1, 2, and 3 years after treatment for primary site were 97. 0 %, 92. 0 % and 86. 0 %, respectively. The disease free survival rate in 1, 2 and 3 years were 97 %, 90 % and 82 0 % respectively. There were no complications of treatment caused by stereotactic radiotherapy. Conclusion 　Stereotactic radiotherapy boost following f ractionated sterreotactic radiotherapy can result in excellent local cont rol and longer diseases free survival.