ABSTRACT
Objective To summarize the outcome of nasopharyngeal carcinoma ( NPC) treated by helical tomotherapy in the Chinese PLA general hospital. Methods Between September 2007 and August 2010, 121 newly diagnosed NPC patients were treated by radiotherapy with Tomotherapy system, with ( n =90) or without ( n = 31) concurrent chemotherapy or molecular target therapy. The prescription dose was 70 - 74 Gy/33f to primary tumor and positive lymph node planning target volume,60. 0 - 62. 7 Gy/33f to high risk planning target volume, and 52 -56 Gy/33f to low risk planning target volume. Acute side-effects were evaluated with RTOG/EORTC criteria. Results The remission rate of primary lesion and positive lymph nodes was 95. 0％ and 99. 0％ , respectively. The follow-up rate was 100％ . The number of patients with 1 ,2 and 3 years followed-up were 99 , 49 , and 7. The 1-, 2-and 3-year local relapse-free survival rates were 97. 30％ , 97. 3％ and 97. 3％ , respectively. The 1-,2-and 3-year nodal relapse-free survival rates were 100％ , 100％ and lOO％, respectively. The 1-, 2-and 3-year distant metastasis-free survival rates were 98. 4％ , 96. 3％ and 96. 3％ , respectively. The 1-, 2-and 3-year overall survival rates were 96. 5％ ,92. 6％ and 86. 8％ , respectively. Acute toxicities of skin, oral mucosa and xerostomia with grade 0,1,2 and 3 were 5. 0％ , 74. 4％ , 15. 7％ and 4. 9％ ; 0. 8％ , 37. 2％ , 57. 9％ and 4. 1％ ; 3. 3％ , 53. 7％ ,43. 0％ and 0％ , respectively. Xerostomia restored with time, no grade 2 or more xerostomia was observed 1 year after radiation therapy. Concurrent chemotherapy significantly increased incidence of mucositis,esophagitis and tracheitis. Conclusion Helical tomotherapy is efficient, secure and effective modality for the treatment of nasopharyngeal carcinoma.
ABSTRACT
Objective To quantify dose variations of the parotid glands and spinal cord in nasopharyngeal carcinoma (NPC) patients during helical tomotherapy (HT) by using megavolt (MV) CT and planned adaptive application. Methods Five patients with advanced local-regional NPC were treated by HT with a prescription dose of 70 Gy in 35 fractions in primary tumor and involved lymph nodes. Daily MV CT scans were registered with the planning CT images. The parotid glands were re-contoured every 4 fractions to a total of 45 times, and location of the spinal cord were corrected by MVCT IGRT system every 2 fractions to a total of 85 times. The actual doses delivered to these organs were evaluated by using the planned adaptive application software of HT system. Results At the end of therapy, the mean volume of the parotid gland was decreased by 42% (left) and 33% (right) , respectively. The average V1 of the parotid was increased by 26. 0% (left) and 31.4% (right), and the D50 increased by 15. 8% (left) and 17. 3% (right), respectively. The average Dmax of the spinal cord was increased by 1.3%. Conclusions During HT, the parotid glands receive a higher actual dose due to the volume shrinkage, while the Dmax of the spinal cord changes little. By using adaptive radiation therapy technique, constant monitoring anatomic changes of organs at risk and selective replanning are necessary during radiation therapy for NPC.