title: MITHRA - multiparametric MR/CT image adapted brachytherapy (MR/CT-IABT) in anal canal cancer: a feasibility study.
abstract: OBJECTIVE
  The aim of this study is to test a novel multiparametric imaging guided procedure for high-dose-rate brachytherapy in anal canal cancer, in order to evaluate the feasibility and safety.
  
  
  METHODS
  For this analysis, we considered all consecutive patients who underwent magnetic resonance/computed tomography image adapted brachytherapy (MR/CT-IABT) treated from February 2012 to July 2014. To conduct this project, we formed a working group that established the procedure and identified the indicators and benchmarks to evaluate the feasibility and safety. We considered the procedure acceptable if 90% of the indicators were consistent with the benchmarks. Magnetic resonance imaging with contrast and diffusion weighted imaging were performed with an MRI-compatible dummy applicator in the anus to define the position of the clinical target volume disease and biological information. A pre-implantation treatment planning was created in order to get information on the optimal position of the needles. Afterwards, the patient underwent a simulation CT and the definite post-implantation treatment planning was created.
  
  
  RESULTS
  We treated 11 patients (4 men and 7 women) with MR/CT-IABT and we performed a total of 13 procedures. The analysis of indicators for procedure evaluation showed that all indicators were in agreement with the benchmark. The dosimetric analysis resulted in a median of V200, V150, V100, V90, V85, respectively of 24.6%, 53.4%, 93.5%, 97.6%, and 98.7%. The median coverage index (CI) was 0.94, the median dose homogeneity index (DHI) was 0.43, the median dose non-uniformity ratio (DNR) resulted 0.56, the median overdose volume index (ODI) was 0.27. We observed no episodes of common severe acute toxicities.
  
  
  CONCLUSIONS
  Brachytherapy is a possible option in anal cancer radiotherapy to perform the boost to complete external beam radiotherapy (EBRT). Magnetic resonance can also have biological advantages compared to the US. Our results suggest that the multiparametric MR/CT-IABT for anal cancer is feasible and safe. This new approach paves the way to prospective comparison studies between MRI and ultrasound-guided brachytherapy (USBT) in anal canal cancer.
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Tagliaferri
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Manfrida
authors.affiliation: Department of Radiological Sciences, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Brunella
authors.initials: B
authors.lastname: Barbaro
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Maria Maddalena
authors.initials: MM
authors.lastname: Colangione
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Masiello
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Gian Carlo
authors.initials: GC
authors.lastname: Mattiucci
authors.affiliation: Physics Institute, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Placidi
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Autorino
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Gambacorta
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Chiesa
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Mantini
authors.affiliation: Interdisciplinary Brachytherapy Unit, University of Lübeck & University Hospital S-H, Campus Lübeck, Germany.
authors.forename: György
authors.initials: G
authors.lastname: Kovács
authors.affiliation: Radiation Oncology Department, Gemelli-ART, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Valentini
keywords: MRI-guided brachytherapy; anal canal cancer; anal carcinoma; brachytherapy; image adapted brachytherapy (IABT)