By Francisco Carnevale
The standard management of benign prostatic hyperplasia is based on the overall health of the patient, on the severity of the lower urinary tract symptoms and on quality-of-life considerations. Voiding difficulties attributable to hyperplasia can be quantified with the International Prostate Symptom Score (IPSS). Various medications can decrease the severity of voiding symptoms secondary to benign prostatic hyperplasia. Impotence, decreased libido and ejaculatory disorders are known side effects.
According to the American Society of Urology (AUA), patients with mild lower urinary tract symptoms secondary to benign prostatic hyperplasia (AUA-SI score <8) and patients with moderate or severe symptoms (AUA-SI score ≥8) who are not bothered by their lower urinary tract symptoms should be managed using a strategy of watchful waiting. If the patient elects interventional therapy and there is sufficient evidence of obstruction, the patient and urologist should discuss the benefits and risks of the various interventions.
Transurethral resection of the prostate is still the gold standard of interventional treatment but it can be associated with bleeding, erectile dysfunction and ejaculatory disorders in up to 10% and 65% of patients, respectively. The substantial prevalence of benign prostatic hyperplasia and its therapies is underscored by the tremendous impact of this condition on the health and quality of life of men. Increasingly benign prostatic hyperplasia therapy trends are moving away from the gold standard operation of transurethral resection of the prostate and toward less invasive pharmacological options and minimally invasive procedures provided in an outpatient setting. When available, new interventional therapies should be discussed. The proof of concept for prostatic artery embolization technique has been widely reported since CIRSE 2008. With nearly four years of follow-up, the multidisciplinary team at University of São Paulo is encouraged by this minimally invasive alternative treatment for patients with lower urinary tract symptoms.
Advantages of embolization
Prostatic artery embolization is a minimally invasive procedure performed under local anaesthesia and as an outpatient procedure. Prostatic artery embolization can be indicated in patients with small or large prostates and does not manipulate the urethra thereby avoiding urethral stenosis. Severe comorbidities such as heart disease, atherosclerosis, patients with metallic implants, penile prosthesis, severe urethral stricture, artificial urinary sphincter, or ASA class group V are not contraindications for prostatic artery embolization (as also applicable to other surgical options). Prostatic artery embolization can also convert an open prostatectomy (prostate volumes greater than 80 to 100mL) to a laser or TURP procedure after reducing the prostate size and avoiding their related complications. Prostatic artery embolization is similar to other surgical options as it can be repeated in the future, if necessary. This procedure has been shown to be safe, effective and with low rate of complications.
Our group is considered as one of the pioneers of prostatic artery embolization for benign prostatic hyperplasia. On 19 June 2008, after carrying out an experimental study of prostatic artery embolization performed in dogs and presented at the SIR meeting in 2008, we started a prospective study including 11 patients with acute urinary retention due to benign prostatic hyperplasia. Working in a research multidisciplinary group with urologists, diagnostic radiologists and interventional radiologists we have performed more than 40 prostatic artery embolization procedures as of March 2012. After confirming good results of the technique in patients at the end-stage-disease (with indwelling catheter due to urinary retention) and nearly a four-year follow-up in our initial patients we have continued this area of research with less symptomatic patients, different study protocols and investigations in this field.
What are the early results?
We have almost four years of follow-up in the first two treated patients and a minimum of 16 months follow-up in all first 11 treated patients. Patients had severe IPSS (with acute urinary retention and indwelling catheters) and now are asymptomatic or have mild symptoms, improving erectile function and quality of life (reported as pleased or delighted) after prostatic artery embolization treatment. Imaging follow-up has shown a mean of 30% prostate reduction (using MRI and ultrasound) and urodynamic findings and symptoms relief have supported this data. Procedures are feasible, safe and effective and early and midterm follow-up after prostatic artery embolization have been excellent.
What are the possible complications with the procedure?
More than 30% of patients were asymptomatic during prostatic artery embolization and the others complained of mild retropubic pain, referred to as a burning sensation for 24 hours. For patients without indwelling catheters, urethral burning during voiding is the most common symptom after prostatic artery embolization. It usually lasts three to seven days and has been treated with non-opioid analgesic and nonsteroidal anti-inflammatory drugs.
Complications after prostatic artery embolization are related to no target embolization to the bladder, rectum and genitals due to the proximity of these organs to the prostate and their vascular communications. In our experience we have observed a few cases where a minimal amount of blood mixed in the stool or urine was reported. A focal bladder ischaemia, incidentally observed during a one month MRI follow-up (asymptomatic patient) disappeared at the three-month control. All these complications may be avoided using microcatheter to perform distal embolization and calibrated microspheres for a predictable embolization. Cone-beam CT is a very useful tool for this procedure.
In my opinion, this is a procedure to be performed by an experienced physician trained in interventional radiology techniques. I recommend superselective microvessel catheterisation to optimally navigate the tortuous and atherosclerotic arteries. A strong understanding of the pelvic vascular anatomy is needed to perform this type of embolization. In addition, inclusion and exclusion criteria using imaging evaluation based on MRI and urodynamic flow are essential. Lastly, a collaborative group effort with urologist is key.
What are the materials being used to carry out the procedure?
Since 2007, when we performed an experimental study of prostatic artery embolization in dogs and presented the results during the SIR 2008, we have been using microcatheters and 300–500μm microspheres for all cases. We do believe that a predictable embolization is one of the keys for the success of prostatic artery embolization.
What is your message to interventionalists regarding the procedure?
Minimally invasive treatments for benign prostatic hyperplasia continue to be part of the therapeutic armamentarium for managing lower urinary tract symptoms; however, cost, changing reimbursement, quality of life and unanswered questions regarding durability of success have tempered the initial enthusiasm for this class of therapy. Prostatic artery embolization has emerged as a new alternative of treatment for symptomatic patients.
All care must be taken for a better understanding of the benign prostatic hyperplasia disease and the best prostatic artery embolization technique to be used. Future larger studies with long-term follow-up and more data supporting prostatic artery embolization are necessary to validate our observations.
Until now our group has treated more than 40 patients with nearly four-year follow-up. This patient population has sustained lower urinary tract symptoms relief and improved their overall quality of life. These data suggest that prostatic artery embolization can be another very interesting minimally invasive alternative of treatment for patients with symptomatic benign prostatic hyperplasia and a promising area for interventional radiologists, but a multidisciplinary approach with urologists, diagnostic radiologists and interventional radiologists provides optimum continuity of care.
Francisco Cesar Carnevale is chief, Interventional Radiology Section, University of São Paulo Medical School. He will be speaking on the topic at GEST 2012 US.