title: Value of apparent diffusion coefficient (ADC) in assessing radiotherapy and chemotherapy success in cervical cancer.
abstract: OBJECTIVE
  We investigated the clinical significance of apparent diffusion coefficient (ADC) values in diffusion-weighted magnetic resonance imaging (DWI) in monitoring the efficacy of radiotherapy (RT) and chemotherapy (CT) treatments in cervical cancer.
  
  
  METHODS
  In order to identify relevant high quality clinical cohort studies reporting the use of DWI in cervical cancers, the following electronic databases in English and Chinese languages were comprehensively searched: MEDLINE, Science Citation Index database, Cochrane Library Database, PubMed, Embase, CINAHL, and Current Contents Index; Chinese Biomedical Database, Chinese Journal Full-Text Database. All selected studies were published prior to March 2014, and data extracted from these studies were analyzed using STATA 12.0 statistical software.
  
  
  RESULTS
  We initially retrieved 196 articles (79 Chinese articles and 117 English articles) through database searches and finally selected sixteen cohort studies for this meta-analysis. The 16 studies contained a combined total of 517 subjects, and all selected studies reported the mean ADC value (10(-3) mm(2)/s) in DWI in cervical cancer patients treated with RT and CT. Combined standardized mean difference (SMD) suggested that the mean post-RT and mean post-CT ADC values were significantly higher than the mean pre-RT and mean pre-CT ADC values, respectively, in cervical cancer patients (SMD=2.95, 95% CI=2.19-3.72, P<0.001). Ethnicity-stratified analysis revealed that increased ADC values were observed post-RT and post-CT in both Caucasian (SMD=1.44, 95% CI=0.93-1.95, P<0.001) and Asian populations (SMD=3.32, 95% CI=2.42-4.22, P<0.001), compared with the mean ADC values before RT and CT, respectively, in the two subgroups. Further, subgroup analysis based on b-value revealed that higher ADC values were found in cervical cancer patients after RT and CT, compared to before RT and CT treatment, with both b value≤900 (SMD=3.71, 95% CI=2.35-5.07, P<0.001) and >900 (SMD=2.55, 95% CI=1.78-3.32, P<0.001). The mean ADC value in patients without residual tumor post-RT and post-CT treatment was significantly higher than seen in patients with residual tumors (SMD=0.80, 95% CI=0.49-1.12, P<0.001).
  
  
  CONCLUSIONS
  Our meta-analysis revealed a significant correlation between mean ADC values and the clinical response to RT and CT treatment. Thus, ADC values in DWI may be effective in evaluating the clinical outcome of treatments in cervical cancer patients.
authors: Department of Oncology, the First Hospital of Qinhuangdao, Qinhuangdao 066000, P.R. China. Electronic address: qhd1h_fzz@126.com.
authors: Zhan-Zhao
authors: ZZ
authors: Fu
authors: Department of Bioengineering, Yanshan University, Qinhuangdao 066000, P.R. China.
authors: Yong
authors: Y
authors: Peng
authors: Department of Oncology, the First Hospital of Qinhuangdao, Qinhuangdao 066000, P.R. China.
authors: Li-Yan
authors: LY
authors: Cao
authors: Division of NMR Research, the First Hospital of Qinhuangdao, Qinhuangdao 066000, P.R. China.
authors: Yan-Sheng
authors: YS
authors: Chen
authors: Department of Chemical Engineering, Yanshan University, Qinhuangdao 066000, P.R. China.
authors: Kun
authors: K
authors: Li
authors: Department of Oncology, the First Hospital of Qinhuangdao, Qinhuangdao 066000, P.R. China.
authors: Bao-Hong
authors: BH
authors: Fu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002584:Cervix Uteri / Q000473:pathology*; D015331:Cohort Studies; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008875:Middle Aged; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy*
keywords: Apparent diffusion coefficient; Cervical cancer; Chemotherapy; Diffusion-weighted MR imaging; Meta-analysis; Radiotherapy