Pathological characteristics of prostate cancer recurrence after radiation therapy: implications for focal salvage therapy

Focal therapy is currently under investigation as an alternative to salvage radical prostatectomy for locally recurrent prostate cancer after primary radiation therapy. If patients can be selected properly, focal therapy could enable tumor eradication without the morbidity associated with salvage radical prostatectomy. We describe the pathological features of recurrent prostate cancer in salvage radical prostatectomy specimens and the implications of these results for focal therapy.

We gathered data on 50 consecutive patients who had recurrence after primary radiation therapy and underwent salvage radical prostatectomy between 1993 and 2008. Preoperatively prostate specific antigen was less than 10 ng/ml in 49 patients (98%) and biopsy Gleason score was 7 or less in 18 (36%). Salvage radical prostatectomy specimens were analyzed for tumor zonal origin, site and volume, Gleason score and pathological stage.

Median preoperative prostate specific antigen was 3.4 ng/ml. Pathological stage was T2 in 23 patients (46%). The salvage radical prostatectomy Gleason score was 7 or less in 17 patients (34%) and surgical margins were negative in 43 (86%). A single cancer focus was found in 33 cases (66%) while there was bilateral involvement in 37 (74%). The base and apex were involved in 23 cases (46%) and 37 tumors (74%) were located within 5.0 mm of the urethra. Median tumor volume was 1.27 cm(3) (range 0.05 to 12.96).

Prostate cancer recurrence after radiation therapy is often bilateral and involves multiple zones. It is often high grade, bulky and close to the urethra. These findings suggest that planning salvage focal therapy after radiation failure will be difficult.