Evaluation of the serum testosterone to prostate‐specific antigen ratio as a predictor of prostate cancer risk

• Published in: BJU international Vol. 105; no. 4; pp. 481 - 484
• Main Authors: Morote, Juan, Planas, Jacques, Ramirez, Cristobal, Gómez, Esther, Raventós, Carles X., Placer, José, Catalán, Roberto, De Torres, Inés M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-02-2010; Wiley-Blackwell
• Subjects: Aged; Biological and medical sciences; Epidemiologic Methods; Gynecology. Andrology. Obstetrics; Humans; Hypogonadism - blood; Hypogonadism - complications; Male; Male genital diseases; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; prediction; prostate cancer; Prostate-Specific Antigen - blood; Prostatic Neoplasms - blood; Prostatic Neoplasms - complications; Prostatic Neoplasms - diagnosis; PSA; ratio; serum testosterone; Testosterone - blood; Tumors; Tumors of the urinary system; Urinary tract. Prostate gland; Evaluation; Nephrology; Urinary system disease; Prognosis; Androgen; Prostate disease; Prediction; Tumoral marker; Malignant tumor; Urology; Prostate specific antigen; Testosterone; Risk factor; Serum; Ratio; Testicular hormone; serum testosterone; Predictive factor; Sex steroid hormone; Male genital diseases; Prostate cancer; Cancer; PSA
• ISSN: 1464-4096; 1464-410X
• DOI: 10.1111/j.1464-410X.2009.08761.x

Study Type – Diagnostic (exploratory cohort)
 Level of Evidence 2b
OBJECTIVE
To analyse the ratio of serum testosterone (sT) to prostate‐specific antigen (PSA) as a predictor of prostate cancer risk, as low levels of sT have been related to a greater risk of prostate cancer, and its ratio with serum PSA level was recently proposed as a new tool to increase the specificity of PSA.
PATIENTS AND METHODS
In all, 439 consecutive men with a normal digital rectal examination and a serum PSA level of 4.1–20 ng/mL had a transrectal ultrasonography‐guided biopsy using a 10‐core scheme, with an additional 1–8 cores according to prostate volume and patient age. The sT level was determined before the procedure using a chemiluminescent assay, and the ratio of sT to PSA (sT/PSA) was calculated after transforming sT measurements from ng/dL to ng/mL. The percentage free PSA (%fPSA) and PSA density were also included in this analysis.
RESULTS
The overall cancer detection rate was 42.1%. The median sT level was 469 ng/dL in men with cancer and 499 ng/dL in those without (P = 0.521). The median sT/PSA was 0.68 and 0.74, respectively (P = 0.215). However, the median %fPSA was 14 in men with cancer and 17 in men without (P < 0.001) and the median PSA density was 0.22 and 0.16, respectively (P < 0.001). The multivariate analysis confirmed the independent predictive value only for %fPSA (odds ratio 0.94, 95% confidence interval 0.91–0.98) and PSA density (5.8, 3.42–19.8).
CONCLUSION
These results do not support the use of sT/PSA for predicting the risk of prostate cancer and to increase the specificity of PSA.