Second to fourth digit ratio: a predictor of prostate‐specific antigen level and the presence of prostate cancer

Abstract

RESULTSNo relationship was found between prostate volume and digit ratio [correlation coefficient ( r ) = − 0.038, P = 0.466]. But, significant negative correlations were found between digit ratio and PSA ( r = − 0.140, P = 0.007). When the patients were divided into two groups (Group A: digit ratio < 0.95, n = 184; Group B: digit ratio ≥ 0.95, n = 182), Group A had a higher mean PSA level than Group B (3.26 ± 5.54 ng/mL vs 1.89 ± 2.24 ng/mL, P = 0.002) and had significantly higher risks of prostate biopsy [odds ratio (OR) = 1.75, 95% CI = 1.07-2.84] and prostate cancer (OR = 3.22, 95% CI = 1.33-7.78). CONCLUSIONSPatients with a lower digit ratio have higher risks of prostate biopsy and prostate cancer. KEYWORDSDigit ratio, prostate volume, prostatespecific antigen, prostate cancer What's known on the subject? and What does the study add? The Homeobox genes, Hox a and d , control urinogenital system differentiation and digit development. The patterns of digit formation may be related to gonad function and may be reflected in 2nd to 4th digit ratio (digit ratio). Digit ratio is negatively correlated with prenatal testosterone levels and androgen receptor activity which is related to the increased prostate cancer risk.Patients with a lower digit ratio have a higher risk of prostate biopsy due to high PSA level, and of prostate cancer. Digit ratio could be a predictor of high PSA level and the presence of prostate cancer.Study Type -Diagnostic (exploratory cohort) Level of Evidence 2b OBJECTIVETo investigate the relationships between the 2nd to 4th digit ratio (digit ratio) and prostate volume, prostate-specific antigen (PSA) level, and the presence of prostate cancer. PATIENTS AND METHODSOf the men that presented with lower urinary tract symptoms (LUTS) at a single tertiary academic center, 366 men aged 40 or older with a PSA level ≤ 40 ng/mL were prospectively enrolled. Right-hand 2nd and 4th digit lengths were measured prior to the PSA determinations and transrectal ultrasonography (TRUS). Prostate volumes were measured by TRUS without information about digit length. Patients with a PSA level ≥ 3 ng/mL underwent prostate biopsy.

Right hand digit ratio (2D:4D) is associated with prostate cancer: Findings of an admixed population study

“…HOX gene family controls the differentiation of fingers and gonads as well as the urogenital system development [6] . Digit ratios could reflect the action of these genes, acting as a putative marker for susceptibility to diseases they are thought to influence [14] .…”

“…Previous studies have investigated correlations between digit ratios and prostate cancer in Korean patients -an expected genetically homogeneous and less susceptible population -and patients from the United Kingdom, a far less admixed sample [6,7] . It is difficult to establish race correlations on multiethnic populations such as Brazilian, and thus ethnic influences seem to play smaller roles than hormonal influences on prostate cancer.…”

“…In fact, every measurement methodology has inherent discrepancies and thus, distortions on the relative lengths may occur. The two other studies regarding digit ratios and prostate cancer used direct measurements and self-reports [6,7] . A standardized method of image capturing was suggested for this study and, if distortions occurred, they were similar for all images.…”

“…Proposition of digit ratio as a predictive marker of the susceptibility to some types of cancer, especially those that show sex differences in their occurrence, progression, and/or prognosis has gained strength [4][5][6][7] .…”

“…This lesion is thought to arise from premalignant conditions such as Benign Prostatic Hyperplasia (BPH) and about 83% of all prostate cancers develop in preexistent sites of BPH. Currently, there are only two studies that addressed correlations between 2D:4D and prostate cancer, and those have been performed in populations that have relatively few ethnic differences [6,7] . Prostate cancer developments could be influenced by in-utero testosterone overexposure, which would reflect in lower digit ratios for individuals that develop this disease.…”