The clinical utility of measuring free-to-total prostate-specific antigen (PSA) ratio and PSA density in differentiating between benign prostatic hyperplasia and prostate cancer

Combined application of information theory on laboratory results with classification and regression tree analysis: analysis of unnecessary biopsy for prostate cancer

BACKGROUND

The probability of a prostate cancer-positive biopsy result varies with PSA concentration. Thus, we applied information theory on classification and regression tree (CART) analysis for decision making predicting the probability of a biopsy result at various PSA concentrations.

METHODS

From 2007 to 2009, prostate biopsies were performed in 664 referred patients in a tertiary hospital. We created 2 CART models based on the information theory: one for moderate uncertainty (PSA concentration: 2.5-10 ng/ml) and the other for high uncertainty (PSA concentration: 10-25 ng/ml).

RESULTS

The CART model for moderate uncertainty (n=321) had 3 splits based on PSA density (PSAD), hypoechoic nodules, and age and the other CART for high uncertainty (n=160) had 2 splits based on prostate volume and percent-free PSA. In this validation set, the patients (14.3% and 14.0% for moderate and high uncertainty groups, respectively) could avoid unnecessary biopsies without false-negative results.

CONCLUSIONS

Using these CART models based on uncertainty information of PSA, the overall reduction in unnecessary prostate biopsies was 14.0-14.3% and CART models were simplified. Using uncertainty of laboratory results from information theoretic approach can provide additional information for decision analysis such as CART.

Evaluation and medical management of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is common among aging men. Untreated BPH may lead to complications including urinary tract infection, acute urinary retention, and obstructive nephropathy. Diagnosing BPH can be challenging because lower urinary tract symptoms are found in conditions other than BPH, and prostate size correlates poorly with symptoms of obstruction. Nonetheless, a careful medical history and physical examination, along with prudent use of diagnostic tests, can yield an accurate diagnosis. We review the evaluation of men with suspected BPH and indications for referral to a urologist for invasive therapy. We also review supporting evidence and treatment considerations for saw palmetto and the 2 major classes of prescription medications, alpha1-adrenergic antagonists and 5alpha-reductase inhibitors.

Relationship of demographic and clinical factors to free and total prostate-specific antigen

OBJECTIVES

To characterize the role of demographic and clinical parameters in the measurements of prostate-specific antigen (PSA), free PSA (fPSA), and percent free PSA (%fPSA).

METHODS

This was a cohort study of volunteers to a randomized screening trial. A central laboratory determined PSA and fPSA for the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. A baseline evaluation of free and total PSA was done for 7183 white, black, Asian, Hispanic, and other male volunteers, aged 55 to 74 years. Comparisons were made across racial and ethnic groups and across a set of clinical parameters from a baseline questionnaire.

RESULTS

The median levels of serum PSA were less than 2.1 ng/mL in each age-race grouping of the study participants. The levels of free and total PSA were higher in black (n = 868, 12%) participants than in white (n = 4995, 70%) and Asian (n = 849, 11.8%) participants. Individuals who identified themselves as ethnically Hispanic (n = 339, 4.7%) had median PSA levels higher than whites who were not Hispanic. The free and total PSA levels increased with age, particularly among men 70 to 74 years old. However, the %fPSA levels showed less variation among the four racial groups or by age. The free and total PSA levels were higher among those who had a history of benign prostatic disease.

CONCLUSIONS

Demographic (age and race/ethnicity) and clinical (history of benign prostatic disease) variables had a moderate effect on the measures of PSA and fPSA and very little effect on %fPSA.

Prostate specific antigen and benign prostatic hyperplasia

Benign prostatic hyperplasia is a common condition in males over 50 years, but prostate cancer can develop in the same population. Prostate specific antigen, the best marker for prostate cancer, is also produced by benign epithelial cells, and there is an overlapping phenomenon between both conditions. The better we understand the relationships between benign prostatic hyperplasia and prostate specific antigen, the higher will be the discrimination power of prostate specific antigen measurement as a marker for prostate cancer. Our scope includes a review of the latest published material to date on this subject.

Aspects of imaging in the assessment and follow up of benign prostatic hyperplasia

For assessing patients suffering from benign prostatic hyperplasia and monitoring subsequent treatment, symptom questionnaires, uroflowmetry, prostate volume measurements, postvoiding residual urine volume measurements and pressure-flow studies may be used. This review highlights aspects of imaging in the assessment of benign prostatic hyperplasia, including volume determinations of prostate and postvoiding residual urine, texture imaging and biopsy guidance. Future developments are also briefly discussed.