The Association of the Second to the Fourth Digit Ratio with Prostate Cancer  Diagnosed by Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Biopsy: A Comperative Analytical Cross-Sectional Analysis of Prospectively Recorded Data

Background: Only a few studies that employed conventional transrectal ultrasound (TRUS) biopsy have investigated the connection between the second digit (2D)-to-fourth digit (4D) ratio and prostate cancer, and their findings have been conflicting. We aimed to investigate the correlation between the 2D:4D ratio and prostate cancer, identified through a multiparametric magnetic resonance imaging (mp-MRI)-TRUS fusion biopsy, and its association with clinically significant prostate cancer (csPCa). Methods: Patients who underwent mp-MRI/TRUS fusion biopsy due to the Prostate Imaging Reporting and Data System 3/4/5 lesions between 2020 and 2024 were included in the study (n = 616). After applying the exclusion criteria, the patients were divided into three groups: Study group (n = 168): prostate cancer; study subgroup: csPCa (n = 95); and control group (n = 360): non-cancer. The groups were compared in terms of demographic data, patient characteristics, MRI characteristics, pathological features, cancer stages, and the right hand 2D:4D ratio. Results: There was a significant difference between the study and control groups for total prostate-specific antigen (PSA) levels, the rate of positive digital rectal examination findings, PSA density, and prostate volume, all favoring the study group (<,001, <,001, <,001, and <,001, respectively). The study and control groups did not show any difference in terms of the right-hand 2D:4D ratio. Similarly, no difference was observed between the study subgroup and control group when the study group was evaluated specifically for csPCa. Conclusions: The right hand 2D:4D ratio is not a dependable predictor for both overall prostate cancer and csPCa risk.