title: A retrospective study of the prognostic value of MRI-derived residual tumors at the end of intensity-modulated radiotherapy in 358 patients with locally-advanced nasopharyngeal carcinoma.
abstract: OBJECTIVE
  To retrospectively analyze the prognostic value of magnetic resonance imaging (MRI)-derived residual tumors after intensity-modulated radiation therapy (IMRT) in the patients with locally-advanced nasopharyngeal carcinoma.
  
  
  METHODS
  A total of 358 patients with locally-advanced nasopharyngeal carcinoma who received IMRT were classified as having residual tumors or no residual tumor based on MRI at the end of radiotherapy. The χ(2) test, log-rank test, Cox proportional hazards regression model and Kaplan-Meir survival curves were used to investigate the relationship of clinicopathological features and residual tumors and to assess the prognostic value of residual tumors.
  
  
  RESULTS
  The 3-year overall survival (OS) rate was 73% in the residual tumor group and 90% in the no residual tumor group (HR 2.15, 95% CI 1.21-3.82,, P = 0.007); 3-year local relapse-free survival (LRFS) was 89% in the residual tumor group and 97% in the no residual tumor group (HR 4.46, 95% CI 1.61-12.38, P = 0.002); 3-year disease free survival (DFS) was 67% in the residual tumor group and 82% in the no residual tumor group (HR 2.21, 95% CI 1.40-3.48, P = 0.001). A high prescribed radiation dose (>73.92 Gy) did not increase the percentage volume of the GTVnx receiving 95% of the prescribed dose (GTVnx V95%) or improve any survival outcome.
  
  
  CONCLUSIONS
  The presence of a residual tumor after IMRT was a significant negative independent prognostic factor for OS, LRFS and DFS. Although IMRT have improved the distribution of radiotherapy doses into the tumors, residual tumors detected by MRI after IMRT are still associated with poor prognosis in patients with advanced nasopharyngeal carcinoma.
authors.affiliation: Department of Oncology, Xiangya Hospital, Central South University, Hunan Province, No. 87, Xiangya Road, Changsha, Hunan Province, 410008, P.R. China. 2541032231@qq.com.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Oncology, Xiangya Hospital, Central South University, Hunan Province, No. 87, Xiangya Road, Changsha, Hunan Province, 410008, P.R. China. qin_zhou2014@yeah.net.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Oncology, Xiangya Hospital, Central South University, Hunan Province, No. 87, Xiangya Road, Changsha, Hunan Province, 410008, P.R. China. linshen2014@yeah.net.
authors.forename: Lin
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Oncology, Xiangya Hospital, Central South University, Hunan Province, No. 87, Xiangya Road, Changsha, Hunan Province, 410008, P.R. China. yajie_zhao@yeah.net.
authors.forename: Yajie
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Oncology, Xiangya Hospital, Central South University, Hunan Province, No. 87, Xiangya Road, Changsha, Hunan Province, 410008, P.R. China. mingjunlei@yeah.net.
authors.forename: Mingjun
authors.initials: M
authors.lastname: Lei
authors.affiliation: Department of Oncology, Xiangya Hospital, Central South University, Hunan Province, No. 87, Xiangya Road, Changsha, Hunan Province, 410008, P.R. China. weiruix@163.com.
authors.forename: Rui
authors.initials: R
authors.lastname: Wei
authors.affiliation: Department of Oncology, Xiangya Hospital, Central South University, Hunan Province, No. 87, Xiangya Road, Changsha, Hunan Province, 410008, P.R. China. lfshen2008@163.com.
authors.forename: Liangfang
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Oncology, Xiangya Hospital, Central South University, Hunan Province, No. 87, Xiangya Road, Changsha, Hunan Province, 410008, P.R. China. shousongc@gmail.com.
authors.forename: Shousong
authors.initials: S
authors.lastname: Cao
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002277:Carcinoma / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D018365:Neoplasm, Residual; D011379:Prognosis; D016016:Proportional Hazards Models; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D015996:Survival Rate
chemical_list: D000970:Antineoplastic Agents