Hypothesis / aims of study
Radiotherapy (brachytherapy {BT} and/or external beam radiotherapy {EBRT}) is considered a standard of care for the treatment of localized prostate cancer but may be accompanied by difficult to manage complications, which include urinary retention and the entire spectrum of lower urinary tract symptoms (LUTS) [1]. Herein, we report our experience with prostatic urethral stones, a relatively uncommon but debilitating complication.
Study design, materials and methods
This is a retrospective case series of men who developed prostatic urethral stones after radiotherapy for prostate cancer. Electronic medical records from two practice settings were queried for men who developed prostatic urethral stones after undergoing external beam and/or brachytherapy radiotherapy. The diagnosis of prostatic urethral stones was based on cystoscopy and/or radiological evaluation.
Specific data culled include age, duration of follow-up, Gleason score, time from radiotherapy to diagnosis of prostatic urethral stones, symptoms, validated symptom scores (the International Prostate Symptom Score {IPSS} and the Lower Urinary Tract Symptom Score {LUTSS}), associated conditions (e.g. urethral stricture, bladder neck contracture, urethral obstruction, overactive bladder), uroflow (Q), post-void residual urine volume (PVR), 24-hour voiding diary, cystoscopy and videourodynamic studies (VUDS), methods of treatment, type and number of surgeries and outcomes.
Results
One hundred ninety-two records of patients with radiation complications were reviewed, and prostatic urethral stones were identified in 12/192 men (6.3%). Median age was 78 years (interquartile range was 12, lower quartile 71, upper quartile 83). All underwent BT, and 4 underwent EBRT as well. Follow-up ranged from 2 months to 15 years with a mean and median of 3.3 years and 2.2 years, respectively. Three patients are still actively being followed.
The mean interval time from radiotherapy to diagnosis of prostate stones was 8 years (range 7 months to 18 years). Seven patients underwent VUDS after stone removal: urethral obstruction was found in these 7 patients and detrusor overactivity in 3/7. All 12 patients from this case series underwent transurethral stone extraction +/- laser lithotripsy. Concomitant surgery included TURP in 5/12 (42%), TUIP in 3/12 (25%), and urethrotomy for urethral strictures in 3/12 (25%). Four out of 12 patients (33%) underwent suprapubic catheter placement at some point. Over time, patients underwent 85 subsequent surgeries to address bladder outlet obstruction, urinary incontinence, etc., including sphincter prosthesis implantation in 4/12 (33%) and explantation in 2/12 (17%), urinary diversion in 2/12 (17%), transurethral procedures (e.g. TUIP, TURP), cystoplasty, open cystolitholapaxy, and additional lithotripsy of prostatic urethral stones. Results are presented in Table 1.
Interpretation of results
Prostate stones are uncommon complications of radiation for prostate cancer. They accounted for 6.3% of men referred to us because of complications of EBRT or BT. Most had signs of radionecrosis of the prostatic urethra and of bulbomembranous stricture. Surgical outcomes were bleak; every patient required multiple interventions and none can be considered a true success. Although one study reported on the brachytherapy seeds as a nidus of stone formation [2], the role of radionecrosis in the genesis of these stones should also be considered.
Initial treatment of prostatic urethral stones in our cohort included lithotripsy, sometimes with concomitant TURP and/or urethrotomy. One patient had such high stone burden that he initially required open cystotomy followed by TURP and urethrotomy.
These patients developed many significant complications and then subsequently underwent a multitude of procedures with minimal success. Our 12 patients underwent a combined total of 85 procedures. Figure 1 depicts one patient’s particularly long saga; this patient, for most of the post-radiotherapy period, had a bad quality of life and still does. At last follow-up, only 3/12 (25%) men are continent—two of whom have a urinary sphincter prosthesis, and one is only 6 months post-op (we have yet to see how this patient will fare long-term in the years to come). In our cohort, only two patients had meaningfully successful long-term outcomes, and both required a number of procedures to achieve that limited success.