Clinical Study of Radiationfields of Intensity Modulated Radiationtherapy(IMRT) and Combination Chemotherapy in Initially Treated Nasopharyngeal Carcinoma
HE Xia, ZHAI Zhen-yu, SONG Dan, et al. (Jiangsu Cancer Hospital, Nanjing 210009, China)
[Purpose] To study radiationfields and clinical efficacy of intensity modulated radiation therapy (IMRT), and the tolerance of radiotherapy alone and radio-chemotherapy in initially treated nasopharyngeal carcinoma (NPC). [Methods] From Dec. 2003 to Dec. 2005, 157 cases of initially treated nasopharyngeal carcinoma underwent full course IMRT including nasopharynx and full neck to supraclavicle with 7 front radiationfields in Jiangsu Cancer Hospital. The prescription dose was 70Gy/32f to gross target volume (GTV1) of nasopharyngeal to nasopharynx, 66Gy/32f to positive neck lymphnodes (GTV2), 60Gy/32f to clinical target volume1(CTV1), and 50.4Gy/28f to CTV2. Eighty-eight patients were treated with combination chemotherapy. Kaplan-Meier method was used for survival analysis, and acute and late toxicities were assessed according to RTOG radiation morbidity scoring criteria. [Results] The results of treatment plan showed that the mean dose of GTV1, GTV2, CTV1 and CTV2 were 70.5Gy, 67.0Gy, 60.1Gy and 51.2Gy respectively. The 1-, 2-year local-regional progression-free survival rates, distant metastases-free survival rates and overall survival rates were 97.4%, 94.9%; 93.6%, 89.4% and 96.4%, 92.7%, respectively with medion follow-up of 16 months. Toxicities of oropharynx, in ucosa, hematologic system in radio-chemotherapy group were higher than those in radiotherapy alone group. Short-term toxicities were tolerable, and xerostomia alleviated with time prolonged. [Conclusion] IMRT can improve the dose of target volume, decrease the dose of surrounding organs, and yield well local-regional control of cancer in initially treated NPC. Radiotherapy combined with chemotherapy is valuable for distant metastasis.