Tiago Bilhim (Saint Louis Hospital, Lisbon, Portugal) presented during the Scientific Paper session at this year’s European Conference on Embolotherapy (22–25 June, Nice, France), and won the award of best abstract for his and co-authors’ ‘Long-term outcome of prostatic artery embolization for patients with benign prostatic hyperplasia’.
Bilhim et al conducted this single-centre retrospective study in 1,072 patients with follow-up over a 10-year period to assess the outcomes of prostatic artery embolization (PAE) for, as stated in paper’s title, benign prostatic hyperplasia (BPH), in patients with lower urinary tract symptoms (LUTS). The authors were able to deem PAE a “safe and effective treatment option for patients with BPH” following the study’s completion, but that various further studies can deepen understanding of the BPH and PAE landscapes.
The authors begin the paper by outlining some of the pre-existing research in the area of PAE for BPH— data have shown that compared to prostatic surgery, PAE can achieve “similar LUTS improvements with a lower adverse event profile.” However, surgery leads to improvement in all BPH objective measurements and data suggest that re-treatment rates for patients who underwent prostatic surgery may also be lower.
In his presentation, Bilhim reported that the study ran from March 2009–19, and the 1,072 patients who were studied excluded those who did not have follow-up (11% of the original study population), the 1% in whom PAE was a technical failure and the 3% who were diagnosed with prostate cancer during follow-up.
Bilhim went on to detail how each patient was evaluated for International Prostate Symptom Score (IPSS) and quality of life (QoL), prostate volume (PV)—measured with transrectal ultrasound—prostate-specific antigen (PSA), peak urinary flow rate (Qmax) and postvoid residual (PVR) volume. Follow-up appointments took place yearly and also evaluated use of prostatic medication, reintervention rates and repeat PAE and prostatectomy rates.
In terms of embolic agent, Bilhim proceeded to explain that over the ten years, various embolic agents were used. These were non-spherical polyvinyl alcohol (PVA) particles, measuring 100–300 micrometres and spherical PVA microspheres, measuring 300–500 micrometres. Some patients received treatment with trisacryl gelatin microspheres measuring 100–500 micrometres, or 250-400 micrometres polyzene-coated hydrogel microspheres. Notably, the first group treated within the study remit received PVA particles, so their follow-up was longer. Mean follow-up time was 4.39±2.37 years.
Adverse events were determined according to Cardiovascular and Interventional Radiology Society of Europe (CIRSE) criteria, and Bilhim stated that they did not consider frequency, urethral burning sensation or slight pelvic pain lasting for one to three days post-PAE as being in category, but rather as post-PAE syndrome. Reintervention, IPSS over 15, or QoL >3 were all considered ‘clinical failure,’ with need for prostatic medication registered but not counted as failure.
Bilhim then proceeded to relay his results to delegates in the audience: at the final follow-up appointment, mean IPSS and QoL improvements were -10.14±8.34 (p<.0001) and -1.87±1.48 (p<.0001) points, mean PV reduction was -6.82±41.11 cm3 (p=0.7779), mean PSA reduction was -1.12±4.60ng/mL (p=0.9713), mean Qmax increase was 2.72±6.38 mL/s (p=0.0005), mean PVR reduction was -8.35±135.75mL (p=0.6786) and mean IIEF-5 improvement was 0.18±7.40 points (p=0.4546).
The number of patients who required prostatic medication after PAE was 335, or 31.3%. The reintervention and repeat PAE rates were 3.4% and 2.3% at one year, 21.1% and 9.5% at five years and 58.1% and 23.1% at 10 years, respectively. Prostatectomy rates were 1.1% at one year, 11.6% at five years and 35.0% at 10 years, Bilhim reported.
The presenter also noted that the study saw a 90% acute urinary retention resolution rate, with the other 10% having to have surgery, and the rate of post-PAE syndrome was 23%.
In terms of difference in outcomes among the different embolic agent groups, the paper acknowledges that PVA led to lower rates of penile skin lesions, haematuria and rectal bleeding after PAE compared to the other spherical embolic agents. A possible explanation for this could be that PVA offers a lower permanent vessel occlusion.
Other trends observed during the study were that unilateral PAE was a significant predictor of clinical failure and reintervention and that those who received a repeat PAE (n=25, 25.8%) were more likely to undergo prostatectomy compared to those who only received one PAE procedure.
Bilhim et al were able to draw the conclusion that PAE gives patients lasting and long-term LUTS relief and that reintervention rates are 20% in the first five years, rising to between 30 and 60% >five years post-PAE. Addressing the ET audience, Bilhim declared PAE a “safe and effective treatment option for patients with BPH.” The study yielded “promising” findings, the presenter added, among which was that 74% of patients remained prostatectomy-free, demonstrating the potential for repeat PAE to ensure treatment effectiveness durability.
Bilhim showed his awareness of his study’s “many limitations”—namely that it was carried out retrospectively with no controls and that they “lost patients during follow-up.” Comparing the embolic agents also made the study more difficult because of different follow-up times for each group, but they did control for this factor with multivariable Cox regression analyses, Bilhim clarified.
He admitted that “we need more long-term data to keep on proving that PAE is a good alternative treatment to prostatectomy/transurethral resection of the prostate (TURP).” Studies with large cohorts are also necessary, Bilhim added, to “fill this gap in the knowledge” around BPH treatment and PAE. Future trials should compare PAE with other minimally invasive surgical treatments (MISTs), as well as look more closely at the differences in outcome when using various embolic agents, Bilhim suggested. Long-term reintervention rates also mean that the benefits of PAE in terms of faster recovery, it being less invasive with fewer adverse events and better at preserving ejaculation, “must be viewed with caution,” Bilhim advised.
Session moderator and meeting deputy chairperson Otto van Delden (University Medical Centers Amsterdam, Amsterdam, The Netherlands) asked Bilhim after he had finished presenting whether “[you can] use [whatever agent] you want.” Bilhim responded in the affirmative, before explaining the following: “What I have seen is that when you do PAE repeatedly, even though I could not prove this, [there seems to be] more recanalisation of the native prostatic artery with PVA than with spherical particles.” Nevertheless, Bilhim asserted, he has seen “no big clinical difference” among the different embolic agents—“all patients will have revascularisation from different origins.”
Regarding the frequently asked question of how PAE compares to other procedures, Bilhim sought to clarify that “you cannot compare recovery and morbidity between PAE and [surgical resection].” It is more appropriate and beneficial to draw comparisons between PAE and other MISTs, such as those which are commonly carried out in the USA.
Rounding up the post-presentation discussion, Bilhim concluded that these study data are “good” for him—” I can tell [patients] about 10-year likely outcomes.”
This study presents the largest PAE cohort with the longest follow-up data so far, with over 900 patients with follow-up data from 1–3 years, over 300 patients with available data at five years and 150 patients up to 10 years. This will be a relevant addition to the existent PAE literature as it presents the first study looking at reintervention rates up to 10 years post-PAE.
The results were published this week online ahead of print in Cardiovasc Intervent Radiol; https://doi.org/10.1007/s00270-022-03199-8.
