Background: The early diagnosis of prostate cancer (PCa) is mainly based on prostate-specific antigen (PSA) blood levels and digital rectal examination. However, this approach may result in a high rate of negative biopsies and increased detection of clinically insignificant PCa (CS-PCa). An important prognostic biomarker, PSA density (PSA-D) demonstrated improved performance in PCa detection compared to PSA. The relationship between prostate volume and the prognostic accuracy of PSA-D remains mostly unclear. The aim of our study is to investigate the PSA-D predictive value of CS-PCa detection at different prostate volumes.
Methods: Using our local radical prostatectomy registry, patients were divided into three prostate size subgroups based on preoperative sonographic prostate volume assessment: less than 50, 50-75, and more than 75 cc. Patients' and PCa characteristics were recorded, including age, body mass index, PSA at diagnosis, prostate volume, PSA-D, D'Amico risk classification, Gleason grade group, and pathological staging following surgery.
Results: The study cohort included 364 patients who underwent Robotic Radical prostatectomy for biopsy-proven clinically localized PCa. 221 (61%) and 143 (39%) patients had PSA-D less than 0.15 and PSA-D more than 0.15, respectively. ISUP GG 1-2 PCa (CS-PCa) was observed in 220 patients (60%), while 144 (40%) had ISUP GG 3-5 PCa at final pathology. PSA-D correlated with CS-PCa only in small and medium-size prostates, but not in large glands (p = .03, p = .01, and p = .36, respectively). The highest sensitivity (72.7%) was observed in small prostates, compared to 3.2% in large prostates. The highest specificity (89.4%) was noted in large prostates. Positive predictive value in small and medium-size prostates was similar (~50%), compared to 20% in large glands. The negative predictive value was slightly better for small and medium-size prostates compared with large glands (68.9%, 73.7%, and 53.1%, respectively). An association between PSA-D and harboring CS-PCa was detected only in small and medium-size glands (72.7% and 43%, respectively).
Conclusion: PSA-D is associated with CS-PCa detection in radical prostatectomy specimens in small and medium-size prostates. The level of PSA-D is directly associated with the ISUP PCa grade group. Therefore, PSA-D is a beneficial, available, and cost-effective tool during decision-making in patients with small and medium-size prostate when considering treatment for PCa.
Keywords: PSA density; biomarkers; clinically significant; prostate cancer.
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