title: Prostate hypofractionated radiation therapy: injection of hyaluronic acid to better preserve the rectal wall.
abstract: OBJECTIVE
  The aim of this study was to evaluate the contribution of an injection of hyaluronic acid (HA) between the rectum and the prostate for reducing the dose to the rectal wall in a hypofractionated irradiation for prostate cancer.
  
  
  METHODS
  In a phase 2 study, 10 cc of HA was injected between the rectum and prostate. For 16 patients, the same intensity modulated radiation therapy plan (62 Gy in 20 fractions) was optimized on 2 computed tomography scans: CT1 (before injection) and CT2 (after injection). Rectal parameters were compared: dose to 2.5 cc (D2.5), 5 cc (D5), 10 cc (D10), 15 cc (D15), and 20 cc (D20) of rectal wall and volume of rectum covered by the 90% isodose line (V90), 80% (V80), 70% (V70), 60% (V60), and 50% (V50).
  
  
  RESULTS
  The mean V90, V80, V70, V60, and V50 values were reduced by 73.8% (P<.0001), 55.7% (P=.0003), 43.0% (P=.007), 34% (P=.002), and 25% (P=.036), respectively. The average values of D2.5, D5, D10, D15, and D20 were reduced by 8.5 Gy (P<.0001), 12.3 Gy (P<.0001), 8.4 Gy (P=.005), 3.7 Gy (P=.026), and 1.2 Gy (P=.25), respectively.
  
  
  CONCLUSIONS
  The injection of HA significantly limited radiation doses to the rectal wall.
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier Lyon Sud, Pierre Benite, France. olivier.chapet@chu-lyon.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Chapet
authors.forename: Corina
authors.initials: C
authors.lastname: Udrescu
authors.forename: Marian
authors.initials: M
authors.lastname: Devonec
authors.forename: Ronan
authors.initials: R
authors.lastname: Tanguy
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Sotton
authors.forename: Ciprian
authors.initials: C
authors.lastname: Enachescu
authors.forename: Marc
authors.initials: M
authors.lastname: Colombel
authors.forename: David
authors.initials: D
authors.lastname: Azria
authors.forename: Patrice
authors.initials: P
authors.lastname: Jalade
authors.forename: Alain
authors.initials: A
authors.lastname: Ruffion
mesh_terms: D019583:Dose Fractionation, Radiation; D057918:Fiducial Markers; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage*; D007267:Injections / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009929:Organ Size; D059351:Organ Sparing Treatments / Q000379:methods; D011467:Prostate / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000517:prevention & control*; D011836:Radiation Tolerance; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000528:radiation effects*; D014057:Tomography, X-Ray Computed; D001743:Urinary Bladder / Q000000981:diagnostic imaging; D055675:Viscosupplements / Q000008:administration & dosage*
chemical_list: D055675:Viscosupplements; D006820:Hyaluronic Acid