Prospective evaluation of a hydrogel spacer for rectal separation in dose-escalated intensity-modulated radiotherapy for clinically localized prostate cancer

BMC Cancer. 2013 Jan 22;13:27. doi: 10.1186/1471-2407-13-27.


Background: As dose-escalation in prostate cancer radiotherapy improves cure rates, a major concern is rectal toxicity. We prospectively assessed an innovative approach of hydrogel injection between prostate and rectum to reduce the radiation dose to the rectum and thus side effects in dose-escalated prostate radiotherapy.

Methods: Acute toxicity and planning parameters were prospectively evaluated in patients with T1-2 N0 M0 prostate cancer receiving dose-escalated radiotherapy after injection of a hydrogel spacer. Before and after hydrogel injection, we performed MRI scans for anatomical assessment of rectal separation. Radiotherapy was planned and administered to 78 Gy in 39 fractions.

Results: From eleven patients scheduled for spacer injection the procedure could be performed in ten. In one patient hydrodissection of the Denonvillier space was not possible. Radiation treatment planning showed low rectal doses despite dose-escalation to the target. In accordance with this, acute rectal toxicity was mild without grade 2 events and there was complete resolution within four to twelve weeks.

Conclusions: This prospective study suggests that hydrogel injection is feasible and may prevent rectal toxicity in dose-escalated radiotherapy of prostate cancer. Further evaluation is necessary including the definition of patients who might benefit from this approach.

Trial registration: German Clinical Trials Register DRKS00003273.

Publication types

  • Clinical Trial

MeSH terms

  • Adenocarcinoma / blood
  • Adenocarcinoma / pathology
  • Adenocarcinoma / radiotherapy*
  • Aged
  • Dose Fractionation, Radiation*
  • Feasibility Studies
  • Germany
  • Humans
  • Hydrogel, Polyethylene Glycol Dimethacrylate / administration & dosage*
  • Injections
  • Kallikreins / blood
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Neoplasm Grading
  • Neoplasm Staging
  • Prospective Studies
  • Prostate-Specific Antigen / blood
  • Prostatic Neoplasms / blood
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms / radiotherapy*
  • Radiation Injuries / etiology
  • Radiation Injuries / prevention & control*
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy, Intensity-Modulated* / adverse effects
  • Rectum / radiation effects*
  • Time Factors
  • Treatment Outcome


  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Kallikreins
  • kallikrein-related peptidase 3, human
  • Prostate-Specific Antigen