title: CT based three dimensional dose-volume evaluations for high-dose rate intracavitary brachytherapy for cervical cancer.
abstract: BACKGROUND
  In this study, high risk clinical target volumes (HR-CTVs) according to GEC-ESTRO guideline were contoured retrospectively based on CT images taken at the time of high-dose rate intracavitary brachytherapy (HDR-ICBT) and correlation between clinical outcome and dose of HR-CTV were analyzed.
  
  
  METHODS
  Our study population consists of 51 patients with cervical cancer (Stages IB-IVA) treated with 50 Gy external beam radiotherapy (EBRT) using central shield combined with 2-5 times of 6 Gy HDR-ICBT with or without weekly cisplatin. Dose calculation was based on Manchester system and prescribed dose of 6 Gy were delivered for point A. CT images taken at the time of each HDR-ICBT were reviewed and HR-CTVs were contoured. Doses were converted to the equivalent dose in 2 Gy (EQD2) by applying the linear quadratic model (α/β = 10 Gy).
  
  
  RESULTS
  Three-year overall survival, Progression-free survival, and local control rate was 82.4%, 85.3% and 91.7%, respectively. Median cumulative dose of HR-CTV D90 was 65.0 Gy (52.7-101.7 Gy). Median length from tandem to the most lateral edge of HR-CTV at the first ICBT was 29.2 mm (range, 18.0-51.9 mm). On univariate analysis, both LCR and PFS was significantly favorable in those patients D90 for HR-CTV was 60 Gy or greater (p = 0.001 and 0.03, respectively). PFS was significantly favorable in those patients maximum length from tandem to edge of HR-CTV at first ICBT was shorter than 3.5 cm (p = 0.042).
  
  
  CONCLUSIONS
  Volume-dose showed a relationship to the clinical outcome in CT based brachytherapy for cervical carcinoma.
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, 5-1-1, Tsukiji Chuo-ku, Tokyo 104-0045, Japan. namuraka@ncc.go.jp.
authors.forename: Naoya
authors.initials: N
authors.lastname: Murakami
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kasamatsu
authors.forename: Akihisa
authors.initials: A
authors.lastname: Wakita
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakamura
authors.forename: Hiroyoki
authors.initials: H
authors.lastname: Okamoto
authors.forename: Koji
authors.initials: K
authors.lastname: Inaba
authors.forename: Madoka
authors.initials: M
authors.lastname: Morota
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ito
authors.forename: Minako
authors.initials: M
authors.lastname: Sumi
authors.forename: Jun
authors.initials: J
authors.lastname: Itami
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D059248:Chemoradiotherapy; D002945:Cisplatin / Q000008:administration & dosage; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008875:Middle Aged; D011879:Radiotherapy Dosage; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*
chemical_list: D002945:Cisplatin