Improving Assessment (and Ultimately Outcomes) of Permanent Prostate Implant Therapy

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00127816
Recruitment Status : Completed
First Posted : August 9, 2005
Last Update Posted : March 16, 2016
Cross Cancer Institute
Information provided by (Responsible Party):
AHS Cancer Control Alberta

August 5, 2005
August 9, 2005
March 16, 2016
April 2005
April 2013   (Final data collection date for primary outcome measure)
implant dose coverage at 4 weeks, comparing CT and MRI versus CT alone
Same as current
Complete list of historical versions of study NCT00127816 on Archive Site
implant edema at time of implant and at 2 and 4 weeks
Same as current
Not Provided
Not Provided
Improving Assessment (and Ultimately Outcomes) of Permanent Prostate Implant Therapy
Improving Assessment (and Ultimately Outcomes) of Permanent Prostate Implant Therapy
Permanent prostate implants are a type of radiation therapy in which a high dose of radiation is delivered to cancerous tissue by many small radioactive "seeds". Studies of early-stage prostate cancer patients treated in this way and followed for 10 - 12 years indicate a cure rate of about 80%. This result is similar to surgery and other forms of radiotherapy, but comes with fewer side effects and greater convenience for the patient. Further studies show that the radiation dose delivered is the most important factor in achieving a cure. At present this dose is estimated by a computer, using a computed tomography (CT) scan of the patient and a simple calculation method. The dose estimate is not as accurate as it could be, however, because the precise extent of the prostate is hard to determine from the CT scan, and the calculation method does not make use of information about patient body tissues. The researchers propose to eliminate these inaccuracies by using magnetic resonance imaging (MRI) to identify the prostate gland and by developing an improved dose calculation algorithm that includes information about patient tissues. This new approach will allow physicians to assess implant quality with greater certainty, improve their implant technique, and ultimately increase the cure rate to as much as 95%.

This study addresses three major sources of post-implant dosimetry inaccuracy for permanent prostate implants: post-operative edema, prostate contour delineation, and dose calculation method. It is hypothesized that a pragmatic edema model can minimize the first uncertainty, co-registered CT + MR images the second, and an improved dose calculation algorithm the third.

Detailed objectives are to:

  • measure and model the effects of edema on dosimetry;
  • evaluate CT + MR image registration methods;
  • compare dosimetry for CT alone vs. CT + MRI using the contemporary TG-43 dose calculation method;
  • set up a Monte Carlo code that makes full use of the information in CT + MR images to perform implant dose calculations;
  • compare prostate dosimetry for the Monte Carlo vs. the simpler TG-43 method;
  • develop an analytical post-implant dose calculation algorithm for routine clinical use (Monte Carlo is too slow on a single-CPU brachytherapy planning computer); and finally
  • assess the performance of the new algorithm.

Of the estimated 250,000 new cases of prostate cancer in North America in 2004, most are early stage disease as a consequence of PSA testing. Permanent prostate implant therapy is a major option for this group, as long-term clinical studies indicate a cure rate equal to surgery and external beam radiotherapy, but with fewer complications. By dealing with dosimetric inaccuracies, a proven treatment can reach its full potential.

Not Applicable
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Prostate Cancer
Procedure: Permanent prostate implant
Not Provided

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Same as current
April 2013
April 2013   (Final data collection date for primary outcome measure)

Inclusion Criteria:

  • Candidate for permanent prostate implant

Exclusion Criteria:

  • Not ambulatory
Sexes Eligible for Study: Male
Child, Adult, Older Adult
Contact information is only displayed when the study is recruiting subjects
SP-14-0044 / 21694
RIP Project 21694
Not Provided
Not Provided
AHS Cancer Control Alberta
AHS Cancer Control Alberta
Cross Cancer Institute
Principal Investigator: Ron Sloboda, PhD AHS Cancer Control Alberta
AHS Cancer Control Alberta
March 2016

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP