How often does the urethra become blocked following prostate cancer treatment?

The authors evaluated the prevalence and management of urethral blockage following certain cancer treatments.

Urethral stenosis is a medical condition characterized by a blockage in the urethra, the tube which drains fluid from the bladder to the outside of the body. The point of the blockage is referred to as the stricture. The hallmark of urethral stenosis is difficulty urinating.

As the male urethra courses through the prostate, it is at risk of injury during prostate cancer treatment. Some of the main treatments for prostate therapy include radical prostatectomy (surgery to remove the prostate) and radiotherapy, including external beam radiotherapy (uses a high-energy x-ray machine to direct radiation to the tumor) and brachytherapy (radioactive seeds are placed in or near the tumor itself). A newer treatment is high intensity focused ultrasound (HIFU); this is a treatment using a machine that gives off high frequency sound waves directed at the tumor. 

The authors aimed to evaluate the prevalence and management of urethral stenosis (blockage) in men undergoing radical prostatectomy and radiation therapy.

Radical prostatectomy: Urethral stenosis occurs in 1.4 – 29% of patients after radical prostatectomy, with lower rates seen in robotic-assisted prostatectomy (1-3%). Risk factors include excessive blood loss during surgery, postoperative urinary leakage, radiotherapy following surgery, current cigarette smoking, older age, obesity and surgeon experience. Stenosis can occur in 42% of patients receiving salvage prostatectomy (treatment of residual or recurring cancer).

Urethral stenosis can occur immediately after or within a year of radical prostatectomy. For stenosis occurring less than 6 weeks after surgery, urethral dilatation is indicated. Urethral dilatation involves gently inserting thin rods of increasing diameters into the urethra from the tip of the penis in order to open up the urethra without causing any further injury. Where this fails, or stenosis occurs after more than 6 weeks after surgery, direct vision internal urethrotomy (a minimally invasive surgery to repair a narrowed section of the urethra) is recommended. Extremely severe stenosis will require a more aggressive approach that will involve reconstructing or diverting the urethra.

Radiotherapy: Most studies of urethral stenosis in patients treated with brachytherapy report rates of 4-9% at 5 years. Risk factors include non-white race, low income, more co-existing diseases, combination therapy with external beam radiation or hormonal therapy and previous prostate surgery undertaken to relieve urinary symptoms caused by an enlarged prostate. History of high blood pressure was also a significant risk factor. Urethral stenosis occurs after external beam radiation therapy in 1-13% of patients, but the risk can increase to 10-18% after 5-10 years.

Post-radiotherapy stenosis may take a few years to appear. Urethral stenosis in these cases may be treated with dilatation or internal urethrotomy. Where these approaches fail, urethroplasty (surgical repair of a stricture) may be adopted, with 73-90% success rates.

High intensity focused ultrasound: Urethral stenosis has been reported to occur in 7-30% of those undergoing this treatment as a first-line (initial) treatment and in 20% of those undergoing this as a salvage treatment. 

The authors provided an account of the current information about urethral stenosis, and call for further investigation into interventional techniques.