Diagnostic Methods in the Detection of Prostate Cancer: Prospective Observational Study

Abstract

Objective: The last decade has seen numerous modifications in the way the prostate cancer is diagnosed. Current diagnostic methods in prostate cancer lacking the ability to predict individual patient outcome, which highlights the need for more sensitive approaches. We investigated the value of digital rectal examination (DRE), transrectal ultrasonography (TRUS) and prostatic specific antigen (PSA) analysis as aids in general clinical practice and in the early detection of prostate cancer. The purpose of this paper is to evaluate the efficiency and effectiveness of analytical and imaging methods for diagnosing prostate cancer in the north-west Spain.Material and Methods: We investigated prospectively two groups of patients (in all 760) with pathological DRE or PSA. Sensitivity (Se), specificity (Sp), Positive predictive Value (PPV), Negative Predictive Value (NPV), Receiver Operating Characteristics (ROC) curves and other analyses were performed to determine the relative contributions of PSA, DRE, TRUS, Colour Doppler Ultrasound (CDUS), symptoms and patient age to cancer prediction.Results: The presence of prostatic disease symptoms did not distinguish between subjects with and without cancer (p=0.8450). The most sensitive (98%) was total PSA (>4 ng/ml) and the most specific were DRE (78%) and TRUS (65%). The contribution of PSA, DRE and TRUS to the diagnosis of prostate cancer was significant (p<0.05). In patients with a PSA of 4-10 ng/ml, using a threshold PSA specificity increased, using a free/total PSA ratio of 15%. Both echographic methods were effective (p<0.05), with greater specificity for CDUS.Conclusion: The PSA continues to be the most sensitive method for prostate cancer diagnosis. DRE tends to be more negative at early stages of cancer detection. Comparing the conventional TRUS echography with the CDUS, the latter is a better detector in the diagnosis of cancer.