title: Cervical cancer outcome prediction to high-dose rate brachytherapy using quantitative magnetic resonance imaging analysis of tumor response to external beam radiotherapy.
abstract: OBJECTIVE
  In order to assess tumor regression and outcomes, a volumetric analysis was conducted for cervical cancer patients treated with magnetic resonance imaging (MRI)-based image-guided brachytherapy (IGBT).
  
  
  METHODS
  Consecutive patients with FIGO stage IB1-IVA cervical cancer receiving chemoradiation from 2007 to 2013 were identified, excluding patients with perineal template-based interstitial brachytherapy or without undergoing MRI. A ring and tandem applicator±interstitial needles was used. T2-weighted imaging was completed following applicator insertion. Gross tumor volumes (GTVs) were retrospectively contoured: initial GTV (GTV(Pre-EBRT)), GTV at first brachytherapy (GTV(IGBT)) and percent residual GTV at first brachytherapy (% GTV(Residual)).
  
  
  RESULTS
  Eighty-four patients were identified. With 20.8-month median follow-up, two-year estimates of local control (LC), disease-free survival (DFS) and overall survival (OS) were 91.3, 79.8, and 85.0%, respectively. Multivariate Cox regression revealed adenocarcinoma (HR 5.88, p=0.03) and GTV(IGBT) (HR 1.17, p<0.01) as predictors for local failure. GTV(IGBT)>7.5 cc was associated with inferior 2-year LC (75.0 vs. 96.6%, p<0.01), DFS (42.6 vs. 91.6%, p<0.01) and OS (65.2 vs. 91.5%, p<0.01). No difference in mean HRCTV D(90) EQD(2) was seen between the groups (p=0.61).
  
  
  CONCLUSIONS
  Aside from known benefits of IGBT, MRI-based planning allows for assessment of tumor regression and prognosticates patients.
authors: Magee-Womens Hospital of University of Pittsburgh Medical Center, Department of Radiation Oncology, USA.
authors: David
authors: D
authors: Minkoff
authors: Magee-Womens Hospital of University of Pittsburgh Medical Center, Department of Radiation Oncology, USA.
authors: Beant S
authors: BS
authors: Gill
authors: Magee-Womens Hospital of University of Pittsburgh Medical Center, Department of Radiation Oncology, USA.
authors: John
authors: J
authors: Kang
authors: Magee-Womens Hospital of University of Pittsburgh Medical Center, Department of Radiation Oncology, USA. Electronic address: beriwals@upmc.edu.
authors: Sushil
authors: S
authors: Beriwal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*
keywords: Brachytherapy; Cervical cancer; MRI; Regression; Response