Focal salvage guided by T2-weighted and dynamic contrast-enhanced magnetic resonance imaging for prostate cancer recurrences.

PURPOSE: Salvage treatment of the entire prostate for local recurrent cancer after primary radiotherapy is associated with high toxicity rates. Our goal was to show that, using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the visualization of a recurrence, focal salvage treatment can be performed, with, potentially, a reduction in toxicity. METHODS AND MATERIALS: We performed MRI, including a DCE sequence, in 7 patients with biopsy-proven locally recurrent prostate cancer. The specific regions of interest suspect for containing tumor were delineated using DCE and T(2)-weighted MRI scans. Subsequently, focal salvage high-dose-rate brachytherapy plans were created to illustrate the principle of focal salvage. Total salvage treatment plans were also created for comparison.
RESULTS: The transfer constant (K(trans)) values from the DCE were 0.33-0.67 min(-1) for areas suspect for tumor and 0.07-0.25 min(-1) for normal tissue. In 4 cases, a focal salvage plan could be generated; 93-100% of the gross tumor volume was covered with the prescribed dose, with relative sparing of the bladder, rectum, and urethra. In the total salvage plans, 24-53% of the gross tumor volume was covered, and the organs at risk received high doses. In 3 cases, a focal salvage plan could not be created because of multifocal tumor, seminal vesicle extension, or capsular extension.
CONCLUSION: Focal salvage treatment plans can be created in patients with local recurrent prostate cancer after radiotherapy. DCE-MRI supports the localization of the target area. This could lead to less toxicity in patients with local recurrent prostate cancer. Copyright (c) 2010 Elsevier Inc. All rights reserved.