title: Implementation of image-guided brachytherapy (IGBT) for patients with uterine cervix cancer: a tumor volume kinetics approach.
abstract: OBJECTIVE
  To evaluate tumor shrinking kinetics in order to implement image-guided brachytherapy (IGBT) for the treatment of patients with cervix cancer.
  
  
  METHODS
  This study has prospectively evaluated tumor shrinking kinetics of thirteen patients with uterine cervix cancer treated with combined chemoradiation. Four high dose rate brachytherapy fractions were delivered during the course of pelvic external beam radiation therapy (EBRT). Magnetic resonance imaging (MRI) exams were acquired at diagnosis (D), first (B1), and third (B3) brachytherapy fractions. Target volumes (GTV and HR-CTV) were calculated by both the ellipsoid formula (VE) and MRI contouring (VC), which were defined by a consensus between at least two radiation oncologists and a pelvic expert radiologist.
  
  
  RESULTS
  Most enrolled patients had squamous cell carcinoma and FIGO stage IIB disease, and initiated brachytherapy after the third week of pelvic external beam radiation. Gross tumor volume volume reduction from diagnostic MRI to B1 represented 61.9% and 75.2% of the initial volume, when measured by VE and VC, respectively. Only a modest volume reduction (15-20%) was observed from B1 to B3.
  
  
  CONCLUSIONS
  The most expressive tumor shrinking occurred in the first three weeks of oncological treatment and was in accordance with gynecological examination. These findings may help in IGBT implementation.
authors.affiliation: Radiotherapy Division.
authors.forename: Heloisa de Andrade
authors.initials: Hde A
authors.lastname: Carvalho
authors.affiliation: Radiotherapy Division.
authors.forename: Lucas Castro
authors.initials: LC
authors.lastname: Mendez
authors.affiliation: Radiotherapy Division.
authors.forename: Silvia Radwanski
authors.initials: SR
authors.lastname: Stuart
authors.affiliation: Radiotherapy Division.
authors.forename: Roger Guilherme Rodrigues
authors.initials: RG
authors.lastname: Guimarães
authors.affiliation: Radiotherapy Division.
authors.forename: Clarissa Cerchi Angotti
authors.initials: CC
authors.lastname: Ramos
authors.affiliation: Magnetic Resonance Division, Departamento de Radiologia e Oncologia Faculdade de Medicina da Universidade de São Paulo, Brazil.
authors.forename: Lucas Assad
authors.initials: LA
authors.lastname: de Paula
authors.affiliation: Radiotherapy Division.
authors.forename: Camila Pessoa
authors.initials: CP
authors.lastname: de Sales
authors.affiliation: Radiotherapy Division.
authors.forename: André Tsin Chih
authors.initials: AT
authors.lastname: Chen
authors.affiliation: Magnetic Resonance Division, Departamento de Radiologia e Oncologia Faculdade de Medicina da Universidade de São Paulo, Brazil.
authors.forename: Roberto
authors.initials: R
authors.lastname: Blasbalg
authors.affiliation: Magnetic Resonance Division, Departamento de Radiologia e Oncologia Faculdade de Medicina da Universidade de São Paulo, Brazil.
authors.forename: Ronaldo Hueb
authors.initials: RH
authors.lastname: Baroni
keywords: MRI; brachytherapy; cervical cancer; cervix cancer