title: Identification of surrogate endpoints in patients with locoregionally advanced nasopharyngeal carcinoma receiving neoadjuvant chemotherapy plus concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone.
abstract: BACKGROUND
  In the era of intensity-modulated radiotherapy (IMRT), the efficacy of additional neoadjuvant chemotherapy (NACT) to concurrent chemoradiotherapy (CCRT) in locoregionally advanced nasopharyngeal carcinoma (NPC) is currently being investigated in ongoing trials. Overall survival (OS) is the gold standard endpoint in NPC trials. We performed this analysis to identify surrogate endpoints for OS, which could shorten follow-up duration and speed up assessment of treatment effects.
  
  
  METHODS
  We retrospectively analysed 208 matched-pair patients with locoregionally advanced NPC receiving NACT+CCRT or CCRT. Progression-free survival (PFS), failure-free survival (FFS), distant failure-free survival (D-FFS) and locoregional failure-free survival (LR-FFS) at 2 and 3 years were assessed as surrogates for 5-year OS according to Prentice's criteria. The strength of the associations were assessed using Spearman's rank correlation coefficient.
  
  
  RESULTS
  No significant differences were observed between treatment arms for any surrogate endpoint at 2 years, which rejected Prentice's second criterion. In contrast, 3-year LR-FFS, PFS, FFS and D-FFS were consistent with all four of Prentice's criteria; the rank correlation coefficient (0.730) between 3-year PFS and 5-year OS was highest.
  
  
  CONCLUSIONS
  3-year PFS, FFS and D-FFS could be valid surrogate endpoints for 5-year OS; 3-year PFS may be the most accurate.
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. chypei@foxmail.com.
authors.forename: Yu-Pei
authors.initials: YP
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. zhangwn@sysucc.org.cn.
authors.forename: Wen-Na
authors.initials: WN
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. tangll@sysucc.org.cn.
authors.forename: Ling-Long
authors.initials: LL
authors.lastname: Tang
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. maoyp@sysucc.org.cn.
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Mao
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. liuxu@sysucc.org.cn.
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. chenlei@sysucc.org.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. zhougq@sysucc.org.cn.
authors.forename: Guan-Qun
authors.initials: GQ
authors.lastname: Zhou
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. maihq@sysucc.org.cn.
authors.forename: Hai-Qiang
authors.initials: HQ
authors.lastname: Mai
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. shaojy@sysucc.org.cn.
authors.forename: Jian-Yong
authors.initials: JY
authors.lastname: Shao
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. jiaweih@mail.sysu.edu.cn.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Jia
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. kangtb@sysucc.org.cn.
authors.forename: Tie-Bang
authors.initials: TB
authors.lastname: Kang
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. zengmsh@sysucc.org.cn.
authors.forename: Mu-Sheng
authors.initials: MS
authors.lastname: Zeng
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. sunying@sysucc.org.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China. majun2@mail.sysu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma; D059248:Chemoradiotherapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000628:therapy*; D020360:Neoadjuvant Therapy / Q000379:methods*; D012189:Retrospective Studies; D016019:Survival Analysis; D055815:Young Adult