Long-term intra-fractional motion of the prostate using hydrogel spacer during Cyberknife® treatment for prostate cancer - a case report

  • Sumila M
  • Mack A
  • Schneider U
 et al. 
  • 19

    Readers

    Mendeley users who have this article in their library.
  • 6

    Citations

    Citations of this article.

Abstract

Background: There is a trend towards hypofractionated stereotactic radiotherapy (RT) in prostate cancer to apply high single doses in a few fractions. Using the Cyberknife® robotic system multiple non-coplanar fields are usually given with a treatment time of one hour or more. We planned to evaluate organ motion in this setting injecting a hydrogel spacer to protect the anterior rectal wall during treatment.Methods: A 66 years old man with low risk prostate cancer was planned for robotic hypofractionated stereotactic RT. After implantation of fiducial markers and a hydrogel spacer a total dose of 36.25 Gy in 5 fractions was given to the planning target volume (clinical target volume + 3 mm). After each beam the corresponding data reporting on the intra-fractional movement were pre-processed, the generated log-files extracted and the data analysed according to different directions: left -right (LR); anterior - posterior (AP); inferior -superior (IS). Clinical assessments were prospectively done before RT start, one week after the end of treatment as well as 1, 6 and 12 months afterwards. Symptoms were documented using Common Toxicity and Adverse Events Criteria 4.0.Results: Tolerability of marker and hydrogel implantation was excellent. A total of 284 non-coplanar fields were used per fraction. The total treatment time for all fields per fraction lasted more than 60 minutes. The detected and corrected movements over all 5 fractions were in a range of +/- 4 mm in all directions (LR: mean 0,238 - SD 0,798; AP: mean 0,450 - SD 1,690; and IS: mean 0,908 - SD 1,518). V36Gy for the rectum was 0.062 ccm. After RT, grade 1-2 intestinal toxicity and grade 1 genitourinarytoxicity occurred, but resolved completely after 10 days. On 1-, 6- and 12-months follow-up the patient was free of any symptoms with only slight decrease of erectile function (grade 1). There was a continuous PSA decline.Conclusions: Prostate movement was relatively low (+/- 4 mm) even during fraction times of more than 60 minutes. The hydrogel spacer might serve as a kind of stabilisator for the prostate, but this should be analysed in a larger cohort of patients.

Author-supplied keywords

  • Hydrogel spacer
  • Intra-fractional motion
  • Prostate cancer
  • Rectal toxicity
  • Stereotactic radiotherapy

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Marcin Sumila

  • Andreas Mack

  • Fabrizio Storelli

  • Ju¨rgen Curschmann

  • Gu¨nther Gruber

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free