Centralized multiinstitutional postimplant analysis for interstitial prostate brachytherapy

Area of Science:

• Radiation oncology
• Medical physics
• Urologic oncology

Background:

• Transperineal interstitial permanent prostate brachytherapy (TIPPB) is a treatment for prostate cancer.
• Standardizing quality assessment across multiple institutions is challenging.
• A pilot study was designed to assess centralized analysis feasibility.

Purpose of the Study:

• To investigate the feasibility and utility of centralized postimplant analysis for TIPPB.
• To compare 125I implant results from five different institutions.
• To establish a basis for multi-institutional trial quality control.

Main Methods:

• Dose-volume histogram (DVH) analysis of 125I implants from five institutions.
• Analysis included implanted activity, prostate volumes (ultrasound and CT), target-volume ratios, homogeneity, dose coverage, and rectal doses.
• Prostate contours were redrawn by a single physician to ensure consistent analysis.

Main Results:

• Differences in TIPPB techniques were identified between institutions based on activity and volume.
• Variability in CT-based prostate contouring was observed, but had minimal impact on dose coverage.
• Rectal doses varied significantly, reflecting differences in implant techniques.

Conclusions:

• Centralized, outcome-based evaluation of TIPPB is viable and appropriate.
• This approach can be effectively used in multi-institutional trials.
• Centralized analysis enhances the reliability of efficacy studies for TIPPB.