Effectiveness and Safety of Prostatic Artery Embolization for the Treatment of Lower Urinary Tract Symptoms from Benign Prostatic Hyperplasia in Men with Concurrent Localized Prostate Cancer

Review by: Sophia Mourad, MS2, Florida State University College of Medicine

Edited by: Neil K. Jain, DO, MedStar Georgetown University Hospital

Introduction

Benign prostatic hyperplasia (BPH) is a common condition in older men where the prostate gland becomes enlarged and causes lower urinary tract symptoms (LUTS). These symptoms include incomplete bladder emptying, urinary dribbling, frequency, and urgency which ultimately decrease the patient’s quality of life. The International Prostate Symptoms Score (IPSS) is a validated 7-item questionnaire that is used to measure the severity of BPH symptoms with scores ranging from 0 (no symptoms) to 35 (severe symptoms). The quality of life (QoL) questionnaire consists of a single question to assess the patients feelings about the state of their urinary condition, with scores from 0 (delighted) to 6 (terrible). Traditional treatment of BPH begins with medical management with alpha blockers and subsequently transurethral resection of the prostate (TURP) if medications deem to be ineffective or symptoms progress. Although TURP is considered the gold standard surgical treatment option for symptomatic BPH refractory to medical therapy, not all patients are good surgical candidates and the procedure comes with adverse effects. These include risk of infection, risk of bleeding, urinary retention, and retrograde ejaculation, along with the significant cost and complications associated with longer hospital stay and general anesthesia [2,3]. These factors have defined a need for a minimally invasive procedure.

Prostatic artery embolization (PAE) has been shown to be effective in treating LUTS resulting from BPH and, as of 2019, is considered an acceptable minimally invasive treatment option for select patients according to various societies of interventional radiology [4,5]. The procedure involves embolization of selected prostatic arteries to cause ischemic necrosis and shrinkage of the prostate gland, resulting in a decrease in symptoms. LUTS are also common in men with prostate cancer (PCa), but the incidence of BPH in these patients is unclear. This highlights a need for further study of PAE for patients with BPH and concomitant PCa with LUTS. 

Suspected PCa is assessed using PI-RADS and Gleason scores. The Prostate Imaging Reporting and Data System (PIRADS) score classifies MRI lesions according to their level of suspicion, on a scale from 1 (very low) to 5 (very high). The Gleason Score is a grading system used to describe how much the cancer looks like healthy tissue when viewed under a microscope, which helps determine the aggressiveness of the prostate cancer. The pathologist assigns a score of 3 to 5 for two different locations on the tumor and adds the numbers to give the total Gleason score, which ranges from 6 (well differentiated) to 10 (poorly differentiated). Treatments under investigation for localized prostate cancer include PAE and Y90 radioembolization [6]. Only one study in 2019 investigated PAE as a palliative measure to treat LUTS in patients with advanced, obstructive prostate cancer [7]. This study investigates the clinical effectiveness and safety of PAE on LUTS from BPH in patients with non-obstructive, localized PCa. 

Study Population and Treatment Protocol

Twenty-one men with localized, non-obstructive prostate cancer had PAE performed for LUTS from BPH. The average age was 72, Gleason score was 7, PIRADS score was 4, PSA was 8.64, prostate volume was 116 cm^3, IPSS score was 20, and QoL score was 4. 

All procedures were performed by a single interventional radiologist. Most of the patients underwent a right transfemoral approach. 2.4-F microcatheters were used to select prostatic arteries. Four-dimensional CT or cone-beam CT were utilized with contrast medium to confirm the position of the catheter. Most embolizations were completed using 300-500μm spherical embolics until stasis in each prostatic artery. 

At 6 and 12 weeks post-procedure, patients answered IPSS and QoL questionnaires, had serum PSA testing, and MR imaging. 13 of 17 patients who were scheduled to receive definitive radiotherapy (RT) after PAE completed the therapy. MRI was used to assess oncologic progression. 

Data Collection and Statistics

The study assessed clinical effectiveness of PAE at 6 and 12 weeks as an IPSS reduction of at least 25% from baseline and absolute score ≤ 15 points, and a QoL decrease of at least 1 point from baseline and absolute score ≤ 3 points. Short-term oncologic progression was also assessed at these time points as: increased PIRADS score index lesion of at least 4, new extracapsular extension, new seminal vesicle invasion, or new pelvic lymphadenopathy. Primary follow-up was performed by the radiation oncology team. Complications post-PAE were identified as either major or minor. Patients were also assessed post-RT for increased PSA and GI and GU toxicity. 

Statistical analysis was performed using SAS for Microsoft Excel. Nonparametric Wilcoxon signed-rank test was used to compare outcomes before and after PAE. P < 0.05 was considered statistically significant.

Results and Outcomes

PAE was considered technically successful in 19 of 21 (90%) patients. It was clinically successful in 18 of 21 (85%) patients at 6 weeks follow-up, signifying a statistically significant decrease in IPSS (median of 12) and improved QoL (median of 2). Median prostate volume and PSA reduction were 24% (range of 2%-69%) and 5.58 (range of -3.0-25.2), respectively, at 6 weeks. A total of 6 patients were lost to follow-up and one patient opted for a prostatectomy instead of RT, leaving 14 patients for clinical follow-up at 12 weeks. At that time, the median IPSS reduction, QoL improvement, prostate volume reduction, and PSA reduction were 14, 3, 36%, and 6.53, respectively. 

In regards to oncologic progression, 16 of the 18 patients who had a baseline MRI underwent follow-up MR imaging at 6 weeks, which demonstrated no new signs of disease progression beyond the prostate, no new PIRADS 4 lesions, and no changes from PIRADS 4 status for existing lesions. At 12 weeks, 8 patients had repeat MR imaging with similar findings and no signs of progression. 

Post-PAE, three patients experienced SIR grade B complications and one experienced an SIR grade C complication. 8 of the 13 patients who completed RT remained in the same clinic for follow-up. The median PSA was 0.04, no patients experienced GU toxicity, and one patient had CTCAE grade 3 rectal toxicity, but recovered.

Conclusion

This study appears to demonstrate the clinical efficacy and safety of PAE for LUTS caused by BPH in patients with PCa. This supports the large body of literature demonstrating the safety and efficacy of PAE for LUTS in BPH [2,4,5]. Additionally, although many patients were lost to follow-up for RT, this study showed that there was no progression of PCa after PAE as seen by MRI. PAE is thought to be safe for patients with PCa, given the low rate of complications, adverse events, and toxicity. 

However, further study is needed to address the various limitations. Limitations of this study include the small sample size, retrospective study design, varied PCa patient demographics, and lack of pathological specimens.

References

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