Transition zone prostate specific antigen density improves prostate cancer detection in Iranian men

Background: Prostate specific antigen (PSA) as a tumor marker has extensively changed the diagnosis of prostate cancer (PCa). With the advent of PSA, the majority of patients are diagnosed with nonpalpable early stage PCa. However, PSA lacks specificity and many patients undergo unnecessary biopsies due to an elevated serum PSA level.

Objectives: This study aimed to assess the sensitivity and specificity of transition zone PSA density (TZPSAD) in detection of PCa.

Patients and methods: This study was performed on 1712 men underwent trans-rectal ultrasound guided prostate biopsy in our institution between March 2008 and March 2013. A total of 1120 men with PSA < 20 ng/mL and normal digital rectal exam were selected for evaluation. Transition zone PSA density was calculated in all patients and the receiver operating characteristic (ROC) curve was used to analyze the accuracy of TZPSAD for the diagnosis of PCa.

Results: Among 1120 men who were eligible for enrolment, prostate cancer was detected in 265 patients. Mean serum PSA levels were 9.7 ± 4.3 ng/mL and 8.5 ± 3.7 ng/mL in patients with and without PCa, respectively (P < 0.001). Mean value for TZPSAD was 1.18 ± 1.19 ng/mL/mL in patients with PCa, whereas it was 0.55 ± 0.84 ng/mL in men without cancer (P < 0.001). Optimal cut-off value for TZPSAD was 0.32 ng/mL. At this cut-off value, the sensitivity and specificity values for TZPSAD were 85% and 45%, respectively. Applying the TZPSAD for PCa screening decreased 50% of unnecessary biopsies.

Conclusions: Using TZPSAD as an adjunct to PSA may improve the specificity of PSA in the diagnosis of PCa and decrease the number of unnecessary prostatic biopsies in Iranian men with serum PSA level < 20 ng/mL.