Stockholm3 validation in a multi-ethnic cohort for prostate cancer (SEPTA) detection: A multicentered, prospective trial.

262Background: Stockholm3 is a multiparametric blood test incorporating germline risk, proteins and clinical data which improves prostate cancer (PC) risk stratification compared to PSA, however no validation exists in an ethnically diverse population. Methods: SEPTA is a prospective trial (NCT04583072) aimed to validate Stockholm3 in an ethnically diverse cohort of men referred for prostate biopsy at 17 North American sites from 2019 to 2023 (supplemented with bio-banked specimens 2008-2020). The trial had two prespecified primary aims when comparing Stockholm3 (≥15) compared to PSA (≥4 ng/ml): (1) Demonstrate non-inferior sensitivity in detecting clinically significant PC (csPC) (defined as ISUP Gleason Grade group ≥2) compared to PSA (non-inferiority margin of 20%). (2) Prove superior specificity thereby reducing the number of biopsies compared to PSA in men with benign or ISUP 1 biopsies. Both aims were assessed using a one-sided alpha of 0.025. A secondary aim was to evaluate Stockholm3 and PSA across ethnic subgroups. Statistical analysis plans were published before the analysis commenced. Results: The study involved 2, 129 biopsied participants, categorized into self-identified groups: African American/Black (24%), White/Caucasian (46%), Hispanic/Latino (14%), and Asian (16%). Median participant age was 63 years. PSA and Stockholm3 median values were 6.1 ng/mL and 17, respectively. A total of 16% underwent MRI-targeted biopsies and 20% had a prior benign biopsy. On either systematic or targeted biopsy, csPC was found in 29%, 14% had ISUP 1 cancer, and 57% benign. The detection rate for csPC across groups were: African American/Black (37%), White/Caucasian (28%), Hispanic/Latino (29%), and Asian (21%). Overall, Stockholm3≥15 showed non-inferior sensitivity compared to PSA≥4 ng/ml (relative sensitivity: 0.95 [95% CI: 0.92-0.99]) and nearly 3 times superior specificity (relative specificity: 2.91 [95% CI: 2.63-3.22]). Results were consistent across ethnic subgroups: non-inferior sensitivity (0.91-0.98) and superior specificity (2.51-4.70). Stockholm3 ≥15 would have reduced benign and ISUP 1 biopsies by 45% overall and between 42-52% across ethnic subgroups compared to PSA ≥4 ng/ml. Stockholm3 exhibited higher AUC (0.82) compared to PSA (0.66), with similar trends in ethnic subgroups. Conclusions: In an ethnically diverse population, Stockholm3 would significantly reduce unnecessary prostate biopsies and diagnosis of ISUP 1 cancer at a similar sensitivity of PSA for detecting clinically significant cancer. Clinical trial information: NCT04583072. [Table Presented]

Duke Scholars

Author Michael R Abern Urology