Stereotactic body radiation therapy (SBRT) following procedures for benign prostatic hyperplasia (BPH): A report on early toxicity.

Abstract

165 Background: When treating patients with prostate cancer, hypofractionation with SBRT takes advantage of radiobiologically favorable factors as compared to conventional fractionation. However, this may increase the risk of urinary toxicity, especially in patients with prior procedures for BPH. Herein, we report early urinary toxicity following SBRT in patients with a history of procedures for BPH. Methods: Thirty three patients treated with SBRT for localized prostate cancer from February 2009 to October 2011 at Georgetown University Hospital with history of a prior procedure for BPH were included in this retrospective analysis. Treatment was delivered using the CyberKnife with doses of 35 Gy-36.25 Gy in 5 fractions. Toxicities were scored using the CTCAE v.3. Cystoscopy findings were retrospectively reviewed. Patient-reported urinary symptoms were assessed using the American Urological Association Symptom Score (AUA). Results: The median age was 70 years (range, 64 - 84). The median follow-up time was 18.7 months (range 9.2 – 38.9). Grade 2 or 3 urinary toxicity occurred in 9 patients and there were no grade 4 or 5 toxicities. Hematuria occurred in 12 patients. The median time to onset of hematuria from SBRT was 6 months (range 1 – 30). Grade 1 hematuria occurred in 7 patients, grade 2 in 4 patients and 1 patient experienced grade 3. Cystoscopy was performed in 9 of these patients at a median time of 9 months (range 3-27). Eight had hyperemia or evidence of bleeding from the prostatic urethra and 5 of these patients also had evidence of bleeding from the bladder neck/wall. All patients except one, who died from other causes, are still being followed and hematuria has resolved in 9 of the 12 patients. The median baseline AUA symptom score of 7 increased to 11 at 1 month, however decreased to a median score of 6 at 3 months. The median AUA symptom score increased to 9 at 1 year. Conclusions: A history of prior transurethral resection of prostate may predispose patients to increased urinary toxicity and hematuria following prostate SBRT. Stricter urethra/bladder neck dosimetric criteria or alternative fractionation regimens may be required to decrease urinary toxicity in these patients.