The association of the second-to-fourth digit ratio with prostate cancer diagnosed by magnetic resonance imaging-transrectal ultrasound fusion biopsy: A comparative analytical cross-sectional analysis of prospectively recorded data

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 (PCa), 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-TRUS fusion biopsy, and its association with clinically significant PCa (csPCa). Patients who underwent multiparametric magnetic resonance imaging/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. The patients were divided into 3 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. 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 right-hand 2D:4D ratio. Similarly, no difference was observed between the study subgroup and the control group when the study group was evaluated specifically for csPCa. In a multivariable regression analysis, age and PSA were found to be independent risk factors; prostate volume and the 2D:4D ratio were not significant after adjustment for other variables. The 2D:4D ratio may not be a dependable predictor for both overall and csPCa risk. Considering the literature data and the results of our study, there is an unclear relationship between the 2D:4D ratio and PCa.