title: Intensity-modulated radiotherapy controls nasopharyngeal carcinoma distant metastasis and improves survival of patients.
abstract: BACKGROUND
  This study evaluated the distant metastatic outcomes in nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT) plus chemotherapy.
  
  
  METHODS
  530 Non-metastatic NPC patients were retrospectively collected and reviewed after receiving IMRT with or without chemotherapy between June 2006 and December 2011. Patients were treated with one fraction of IMRT daily for 5 days a week for 69.96-74.09 Gy, while 473 (89.2 %) of patients also received chemotherapy.
  
  
  RESULTS
  Patients were followed up for a median follow-up duration of 49 months (range from 5 to 98 months). After treatment, 91 (17.3 %) patients developed distant metastasis. Distant metastasis after treatment was significantly associated with advanced 2010 Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) T staging (p = 0.034), N stage (p < 0.001), 2010 UICC/AJCC stage (p < 0.001), and tumor recurrence (p = 0.029). However, chemotherapy failed to reduce cancer distant metastasis in early stage patients, the distant metastasis rate was 17.5 % in stage III and 24.2 % in stage IVA-B diseases, after IMRT and chemotherapy. The multivariate analysis showed that cancer remission duration, treatment modality, and metastatic site (p < 0.001, p = 0.027 and p = 0.022, respectively) were all independent predictors for overall survival of NPC patients after IMRT and chemotherapy.
  
  
  CONCLUSIONS
  This study provided insight into the effects of IMRT plus chemotherapy in the treatment of NPC. Future studies will explore the efficacy of more aggressive systemic therapies for high-risk patients with distant metastasis.
authors.affiliation: Department of Radiation Oncology, Guangxi Medical University Cancer Hospital, No. 71 Hedi Road, Nanning, 530021 China.
authors.forename: Xiaoqian
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, Guangxi Medical University Cancer Hospital, No. 71 Hedi Road, Nanning, 530021 China.
authors.forename: Hao
authors.initials: H
authors.lastname: Lei
authors.affiliation: Department of Radiation Oncology, Guangxi Medical University Cancer Hospital, No. 71 Hedi Road, Nanning, 530021 China.
authors.forename: Zhongguo
authors.initials: Z
authors.lastname: Liang
authors.affiliation: Department of Radiation Oncology, Guangxi Medical University Cancer Hospital, No. 71 Hedi Road, Nanning, 530021 China.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Guangxi Medical University Cancer Hospital, No. 71 Hedi Road, Nanning, 530021 China.
authors.forename: Song
authors.initials: S
authors.lastname: Qu
authors.affiliation: Department of Radiation Oncology, Guangxi Medical University Cancer Hospital, No. 71 Hedi Road, Nanning, 530021 China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhu
keywords: Intensity-modulated radiotherapy; Metastasis; Nasopharyngeal carcinoma; Prognosis