What is the 'normal range' for prostate-specific antigen? Use of a receiver operating characteristic curve to evaluate a serum marker

Lower urinary tract symptoms in men

Benign prostatic hyperplasia (BPH) is a highly prevalent and costly condition that affects older men worldwide. Many affected men develop lower urinary tract symptoms, which can have a negative impact on their quality of life. In the past, transurethral resection of the prostate (TURP) was the mainstay of treatment. However, several efficacious drug treatments have been developed, which have transformed BPH from an acute surgical entity to a chronic medical condition. Specifically, multiple clinical trials have shown that α adrenoceptor antagonists can significantly ameliorate lower urinary tract symptoms. Moreover, 5α reductase inhibitors, alone or combined with an α adrenoceptor antagonist, can reverse the natural course of BPH, reducing the risk of urinary retention and the need for surgical intervention. Newer medical regimens including the use of antimuscarinic agents or phosphodiesterase type 5 inhibitors, have shown promise in men with predominantly storage symptoms and concomitant erectile dysfunction, respectively. For men who do not adequately respond to conservative measures or pharmacotherapy, minimally invasive surgical techniques (such as transurethral needle ablation, microwave thermotherapy, and prostatic urethral lift) may be of benefit, although they lack the durability of TURP. A variety of laser procedures have also been introduced, whose improved hemostatic properties abrogate many of the complications associated with traditional surgery.

Advances in gas chromatographic methods for the identification of biomarkers in cancer

Screening complex biological specimens such as exhaled air, tissue, blood and urine to identify biomarkers in different forms of cancer has become increasingly popular over the last decade, mainly due to new instruments and improved bioinformatics. However, despite some progress, the identification of biomarkers has shown to be a difficult task with few new biomarkers (excluding recent genetic markers) being considered for introduction to clinical analysis. This review describes recent advances in gas chromatographic methods for the identification of biomarkers in the detection, diagnosis and treatment of cancer. It presents a general overview of cancer metabolism, the current biomarkers used for cancer diagnosis and treatment, a background to metabolic changes in tumors, an overview of current GC methods, and collectively presents the scope and outlook of GC methods in oncology.

Recent advances in biomarkers for cancer diagnosis and treatment

With the availability of new technologies and the increased interest of medical practitioners to use molecular biomarkers in early detection and diagnosis, and in the prediction of therapeutic treatment efficacy and clinical outcomes, the academic and research institutions, as well as the pharmaceutical industry, have increased their efforts to develop novel molecular biomarkers for several human diseases, including cancer. The identification of molecular biomarkers also enables the development of a new generation of diagnostic products and to integrate diagnostics and therapeutics. This integrated approach will aid in 'individualizing' the medical practice. Here, we address issues related to the development of biomarkers, novel technological platforms used for drug development, future technologies and strategies for validating biomarkers for their clinical utility.

Biomarkers in molecular medicine: cancer detection and diagnosis

In spite of advances in diagnostics and therapeutics, cancer remains the second leading cause of death in the U.S. Successful cancer treatment depends not only on better therapies but also on improved methods to assess an individual's risk of developing cancer and to detect cancers at early stages when they can be more effectively treated. Current cancer diagnostic imaging methods are labor-intensive and expensive, especially for screening large asymptomatic populations. Effective screening strategies depend on methods that are noninvasive and detect cancers in their early stages of development. There is increasing interest and enthusiasm in molecular markers as tools for cancer detection and prognosis. It is hoped that newly discovered cancer biomarkers and advances in high-throughput technologies would revolutionize cancer therapies by improving cancer risk assessment, early detection, diagnosis, prognosis, and monitoring therapeutic response. These biomarkers will be used either as stand-alone tests or to complement existing imaging methods.

Prostate Cancer - Old Problems and New Approaches. (Part II. Diagnostic and Prognostic Markers, Pathology and Biological Aspects)

Diagnostic and prognostic markers for prostatic cancer (PCa) include conventional protein markers (e.g., PAP, PSA, PSMA, PIP, OA-519, Ki-67, PCNA, TF, collagenase, and TIMP 1), angiogenesis indicator (e.g., factor VIII), neuroendocrine differentiation status, adhesion molecules (E-cadherin, integrin), bone matrix degrading products (e.g., ICPT), as well as molecular markers (e.g., PSA, PSMA, p53, 12-LOX, and MSI). Currently, only PSA is used clinically for early diagnosis and monitoring of PCa. The histological differential diagnosis of prostatic adenocarcinoma includes normal tissues such as Cowper's gland, paraganglion tissue and seminal vesicle or ejaculatory duct as well as pathological conditions such as atypical adenomatous hyperplasia, atrophy, basal cell hyperplasia and sclerosing adenosis. A common PCa is characterized by a remarkable heterogeneity in terms of its differentiation, microscopic growth patterns and biological aggressiveness. Most PCa are multifocal with signi ficant variations in tumor grade between anatomically separated tumor foci. The Gleason grading system which recognizes five major grades defined by patterns of neoplastic growth has gained almost uniform acceptance. In predicting the biologic behavior of PCa clinical and pathological stages are used as the major prognostic indicators. Among the cell proliferation and death regulators androgens are critical survival factors for normal prostate epithelial cells as well as for the androgen-dependent human prostatic cancer cells. The androgen ablation has been shown to increase the apoptotic index in prostatic cancer patients and castration also promotes apoptotic death of human prostate carcinoma grown in mice. The progression of PCa, similarly to other malignancies, is a multistep process, accompanied by genetic and epigenetic changes, involving phenomenons as adhesion, invasion and angiogenesis (without prostate specific features).

Knowledge, attitudes, and screening practices among older men regarding prostate cancer

OBJECTIVES

This study determined population-based rates of reported prostate cancer screening and assessed prostate cancer-related knowledge, attitudes, and screening practices among men in New York aged 50 years and older.

METHODS

Two telephone surveys were conducted. One was included in the 1994 and 1995 statewide Behavioral Risk Factor Surveillance System interviews, and the other was a community-level survey that targeted Black men (African-American Men Survey). Prevalence estimates were computed for each survey, and prostate cancer screening practices were assessed with logistic regression models.

RESULTS

Overall, fewer than 10% of the men in each survey perceived their prostate cancer risk to be high; almost 20% perceived no risk of developing the disease. Approximately 60% of the men in each survey reported ever having had a prostate-specific antigen (PSA) test. In both surveys, physician advice was significantly associated with screening with a PSA test or a digital rectal examination. Also, race was significantly associated with screening in the statewide survey.

CONCLUSIONS

Many New York men appear to be unaware of risk factors for prostate cancer. However, a substantial percentage reported having been screened for the disease; physician advice may have been a major determining factor in their decision to be tested.

Prostate cancer screening trends of New York State men at least 50 years of age, 1994 to 1997

BACKGROUND

Despite the lack of consensus on prostate cancer screening recommendations, men are being screened at high rates in some states. Our objective was to examine the trends in prostate cancer screening awareness and practices from 1994 through 1997 and the relationship among screening practices and demographic characteristics, perceived risk, and family history of prostate cancer.

METHODS

Data from the New York State Behavioral Risk Factor Surveillance System surveys and questionnaire modules on prostate cancer screening were used for this study, which excluded men younger than 50 years of age and men with a history of prostate cancer. The questionnaires were administered by random-digit-dialed monthly telephone surveys of the civilian, noninstitutionalized adult population in New York State.

RESULTS

A total of 295, 336, 273, and 448 men, the vast majority of whom were white, met the study criteria for 1994, 1995, 1996, and 1997, respectively. Each year the percentage of men who reported having heard of the prostate specific antigen (PSA) test increased (test for trend, P < 0.001). Among those who had heard of the PSA test, the percentage who reported having had a PSA test increased steadily from 1994 to 1997. About 30% of the men in each year's study did not have an impression of their risk of getting prostate cancer.

CONCLUSIONS

Given the increasing rate at which men are reporting being screened for prostate cancer and given their reported perceived risk levels, perhaps more needs to be done to educate men about screening implications and personal risk for prostate cancer.

High rates of prostate-specific antigen testing in men with evidence of benign prostatic hyperplasia

PURPOSE

Benign prostatic hyperplasia is common among men who may be candidates for prostate cancer screening using prostate-specific antigen (PSA) testing. Patterns of PSA testing among men with evidence of benign prostatic hyperplasia have not been studied.

METHODS

We examined the prevalence and correlates of a self-reported history of PSA testing. In 1994, 33,028 US health professionals without prostate cancer aged 47 to 85 years provided information on prior PSA testing, lower urinary tract symptoms characteristic of benign prostatic hyperplasia, history of prostatectomy, and prostate cancer risk factors. In 1995, a subset of 7,070 men provided additional information on diagnosis and treatment of benign prostatic hyperplasia.

RESULTS

From 39% of men in their 50s to 53% of men in their 80s reported PSA testing in the prior year (P <0.0001 for trend with age). Men were more likely to report PSA testing if they had lower urinary tract symptoms characteristic of benign prostatic hyperplasia (age-adjusted odds ratio for severe symptoms 2.2, 95% confidence interval 1.8 to 2.6), a prior history of prostatectomy (age-adjusted odds ratio 1.1, 95% confidence interval 1.02 to 1.2), or a physician diagnosis of benign prostatic hyperplasia (odds ratio 1.9, 95% confidence interval 1.7 to 2.2; adjusted for age, signs or symptoms of benign prostatic hyperplasia, and prostate cancer risk factors).

CONCLUSIONS

These US health professionals reported preferential use of PSA testing among men least likely to benefit from early cancer detection (older men) and among men most likely to have a false-positive PSA result (men with benign prostatic hyperplasia). Physician and patient education are needed to promote more rational and selective use of this screening test.

Diagnostic and prognostic markers for human prostate cancer

BACKGROUND

The incidence and mortality of prostate cancer are increasing at alarming rates, partially due to an aging population. Early detection of prostate cancer, using clinically sensitive procedures and/or tumor markers (e.g., prostate-specific antigen [PSA]), is of prime importance. However, the choice of therapeutic interventions for prostate cancer at the time of diagnosis is largely dependent on clinical and pathologic staging and prediction of the degree of aggressiveness of the disease. Clinically applicable prognostic markers are urgently needed to assist in the selection of optimal therapy.

METHODS

Literature review of the potential diagnostic and prognostic markers for human prostate cancer.

RESULTS

Well-established tissue prognostic indicators, including histologic grade, margin positivity, pathologic stage, intraglandular tumor extent, and DNA ploidy, are not reviewed in this paper. Recently, a number of novel markers have been identified. In this paper, we begin with a discussion of a number of well-established as well as investigational diagnostic markers and then focus on evaluation of prognostic markers. Diagnostic markers that have prognostic value and investigational prognostic markers are also discussed.

CONCLUSIONS

Currently, only PSA is utilized for early diagnosis and monitoring of prostate cancer. A number of potential prognostic markers warrant further investigation. Multimarker analysis is implicated.

Interpreting results of prostate-specific antigen testing for early detection of prostate cancer

OBJECTIVE

Calculation of likelihood ratios for serum prostate-specific antigen (PSA) levels to discriminate potentially curable prostate cancer in men selected for having benign prostatic hyperplasia (BPH) or in randomly selected men.

DESIGN

Retrospective analysis of prospectively measured PSA levels.

SETTING

A tertiary referral center, a multicenter randomized controlled trial, and a community-based study, all providing PSA data.

PATIENTS

We used PSA measurements from four groups of men aged 50 to 79 years: 276 men with organ-confined prostate cancer treated with radical prostatectomy, 305 randomly selected men without clinical evidence of prostate cancer or a history of surgery for BPH recruited for a community study, 173 men without cancer but with BPH coming to prostatectomy, and 770 men without cancer and with symptoms of BPH enrolled in the North American finasteride clinical trial.

MEASUREMENTS AND MAIN RESULTS

Age-standardized, stratum-specific likelihood ratios for organ-confined prostate cancer were calculated separately for unselected men in the community sample and for selected men with BPH (pooling both BPH populations). Likelihood ratios ranged from 0.2 for PSA between 0.0 and 2.0 ng/mL to 54.8 for a PSA level of 10.1 ng/mL or higher in unselected men, but rose to only 2.9 for PSA values of 10.1 ng/mL or higher in men with BPH. Forty percent of the men in the community study had moderate to severe lower urinary tract symptoms. In these men, likelihood ratios ranged from 0.2 for PSA values between 0.0 and 2.0 ng/mL to 17.2 for PSA values of 6.1 ng/mL or higher, while in men with no or mild symptoms, likelihood ratios rose to 26.9 for PSA values of 6.1 ng/mL or higher.

CONCLUSIONS

Likelihood ratios for PSA test results allow stratification of men along a continuum of risk for prostate cancer. Likelihood ratios demonstrate that the ability of the PSA test to discriminate potentially curable prostate cancer from BPH is dramatically lower in men selected with lower urinary tract symptoms than in randomly selected men.