Topography of Prostate Cancer Recurrence After Radiation Therapy: A Detailed Mapping Study of Salvage Radical Prostatectomy Specimens

In men who do not respond to initial radiation therapy, accurate knowledge of the site of cancer recurrence or persistence is necessary to understand treatment failure. We evaluated the pathologic characteristics of recurrent/persistent prostate cancer with tumor maps from the whole-mount slides of salvage radical prostatectomies performed between 2000 and 2014. Of 216 consecutive patients, detailed tumor maps were available for 77. Sixty-nine patients (90%) were found to have tumor in the apex, of which 46% occurred in the most apical 3 mm. Fifty-three patients (69%) had tumors at a distance of ≤5 mm from the urethra. Five patients had tumor directly involving the urethra, all of whom had urethral invasion at the apex. Seminal vesicle involvement was seen in 32 patients (42%), two of whom had tumor only in the seminal vesicles. Sixty-two patients (81%) had tumors in the distal apex, periurethral area, or seminal vesicles, that is, areas that are not routinely biopsied. Targeting these areas could improve the accuracy of biopsy when cancer recurrence is suspected. Patient summary: When recurrence is suspected, clinicians should include biopsy of the distal apex, areas surrounding the urethra, and seminal vesicles. This information will help tailor successful salvage treatments. When recurrence of prostate cancer after radiation therapy is suspected, biopsy focused on the distal apex, periurethral area, and seminal vesicles—areas that are not routinely biopsied—is necessary.