PI-RADS-stratified MRI-based PSA Density for Predicting Adverse Pathology after Robotic-assisted Laparoscopic Radical Prostatectomy.

BACKGROUND

In the modern magnetic resonance imaging (MRI) era, prostate-specific antigen (PSA) density (PSAD) derived from multiparametric MRI (mpMRI) has become an accessible biomarker for risk stratification in localized prostate cancer. Although widely used, the optimal PSAD threshold for predicting adverse pathology and long-term oncologic outcomes after radical prostatectomy remains uncertain.

OBJECTIVE

To determine the prognostic utility and optimal cutoff of MRI-based PSAD in predicting adverse pathology and oncologic outcomes among men undergoing robotic-assisted laparoscopic radical prostatectomy (RALP).

DESIGN, SETTING, AND

PARTICIPANTS

This study analyzed a prospectively maintained MRI-era cohort of 788 consecutive patients who underwent RALP between 2006 and 2023. All patients had preoperative mpMRI with volumetric assessment, pathology data, and long-term follow-up for biochemical and metastatic progression. The primary endpoint was adverse pathology, defined as ≥pT3 disease, Grade Group ≥4, seminal vesicle invasion (SVI), lymph-node positivity, or positive surgical margin (PSM). Secondary outcomes included biochemical recurrence-free survival (BRFS).

RESULTS

Median age was 62.5 yr, median was PSA 6.7 ng/ml, median prostate volume was 40.0 ml, and median MRI-based PSAD was 0.16 ng/ml/cm3. Adverse pathology occurred in 43% of patients, with 15.7% harboring PSMs, 7.4% SVI, and 4.7% nodal involvement. On multivariable analysis, MRI-based PSAD independently predicted adverse pathology (odds ratio [OR] 15.633, p < 0.001), SVI (OR 2.614, p = 0.040), PSM (OR 3.650, p = 0.028), and PSA persistence (OR 4.463, p = 0.004). Decision-curve analysis demonstrated that PSAD ≥ 0.10 ng/ml/cm3 provided the greatest overall net benefit in Prostate Imaging-Reporting and Data System (PI-RADS) ≥3 for predicting adverse pathology, while PSAD ≥0.15 ng/ml/cm3 achieved better specificity and performed best in men with PI-RADS ≤2. Kaplan-Meier analyses showed significantly worse BRFS for PSAD ≥0.15 ng/ml/cm3 versus <0.15 ng/ml/cm3 in PI-RADS ≤2 (p = 0.002) and for PSAD ≥0.10 ng/ml/cm3 versus <0.10 ng/ml/cm3 in PI-RADS ≥3 (p = 0.001).

CONCLUSIONS

MRI-based PSAD is a strong, independent predictor of adverse pathology and oncologic outcomes after RALP in the MRI era. A threshold of 0.15 ng/ml/cm3 offers the most balanced clinical utility in men with PI-RADS ≤2 lesion, whereas 0.10 ng/ml/cm3 may be more appropriate in men with PI-RADS ≥3 lesion.