Lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH) are a widely prevalent medical problem that affects the aging male population worldwide.¹ Surgical interventions are offered if patients fail or are unwilling/unable to tolerate medical therapy.² Holmium laser enucleation of the prostate (HoLEP) is a size-independent treatment option for BPH.² While preoperative testing may often include cross-sectional imaging for prostate sizing and PSA screening, incidental prostate cancer (iPCa) at HoLEP can be identified in 3.6% to 23.3% of patients.^3-8 The majority of these patients will have low-volume, Gleason Grade Group (GG) 1 prostate cancer, which is suitable for active surveillance (AS) or watchful waiting, with only 3% of patients requiring prostate cancer treatment in our institutional cohort.⁹

So when is multiparametric MRI (mpMRI) beneficial for follow-up of post-HoLEP patients? Our institutional pathway for post-HoLEP AS has been previously described and is displayed in the Figure.⁹ We obtain a post-HoLEP baseline PSA for all patients at 3 months postoperatively and then at 6-month intervals for those men with iPCa. In patients with greater than 10-year life expectancy and either incidental clinically significant prostate cancer (icsPCa; GG2 or higher) or GG1 PCa with > 5% specimen involvement (pT1b), surveillance mpMRI and prostate needle biopsy are recommended. Low-risk patients with GG1 PCa and < 5% specimen involvement may undergo PSA monitoring every 6 months, with for-cause mpMRI and consideration for prostate biopsy if PSA ≥ 1 ng/mL or PSA velocity ≥ 0.5 ng/mL/y. Those who have icsPCa should undergo planned surveillance biopsy regardless of mpMRI results, whereas lower-risk patients with GG1 PCa may be risk stratified and continue to biopsy if the mpMRI has radiographically significant (Prostate Imaging Reporting and Data System [PIRADS] 3-5) lesions.

At our institution, we identified 104 iPCa (12.8%) HoLEP patients between January 2021 and July 2022, with icsPCa detected in 4.4% (36/811). Post-HoLEP mpMRI was obtained in 42 patients, 31% with a PIRADS 3 lesion and 24% with a PIRADS 4 lesion. Confirmatory biopsy was obtained in 14 patients, with csPCa concordance rates of 0% and 22% (2/9) for PIRADS 3 and 4, respectively. In Korea, Ko et al⁸ reported an iPCa rate of 3.6% (64/1764) among patients who underwent HoLEP from 2009 to 2022 and utilized a similar follow-up algorithm. There were 62 patients who underwent mpMRI, and the study found that mpMRI was particularly useful in risk stratification of GG1 to GG2 patients in determining whether to pursue AS or active treatment. Of the patients with icsPCa, 66.7% with PIRADS 3 to 4 lesions underwent AS. In this study, mpMRI was used as the primary factor to determine candidacy for AS and patients did not undergo subsequent prostate biopsy. In contrast, at our institution, those with icsPCa or pT1b GG1 underwent surveillance biopsy regardless of mpMRI result, and patients with pT1a GG1 PCa who received mpMRI for cause generally proceeded with prostate biopsy if PIRADS 3 to 5 was identified on mpMRI.

In the literature regarding transurethral resection of the prostate, mpMRI has been shown to have significant value in detecting csPCa in the peripheral zone.¹⁰ However, it was not shown to be valuable in detecting transitional zone lesions and may have decreased accuracy after BPH surgery.^10,11 This finding may be more prevalent in the early postoperative period given the potential for hemorrhage, edema, inflammation, or fibrosis to lead to false positives.^12,13 Therefore, generally we would wait 3 to 6 months prior to obtaining postoperative mpMRI.

In conclusion, we find that while the vast majority of iPCa post HoLEP is low grade, mpMRI does play a role in detection of csPCa post BPH surgery. It should be utilized in combination with clinical characteristics such as age, medical comorbidities, and life expectancy as well as advanced tools such as PSA, PSA density, prostate health index, percent free PSA, and genomic classifiers such as Decipher to risk stratify patients and determine whether AS or definitive treatment should be pursued. Further studies with longer follow-up and integration of these advanced diagnostic tools are necessary to determine the ideal risk stratification and AS protocol for patients with iPCa at HoLEP.

Conflicts of Interest: Dr Krambeck is a consultant for Ambu, Boston Scientific, Lumenis, Sonomotion, and Virtuoso Surgical, and a board member of Sonomotion and Uriprene. Dr Ross is a consultant for Astellas, Bayer, Blue Earth, BillionToOne, Boston Scientific, Janssen, Pfizer, Sumitomo Pharma, Lantheus, and Veracyte. No other disclosures were reported.