Prostate cancer is the second leading form of male cancer in the United States and this would seem to indicate the need for vigilant screening. The problem is the serious controversy regarding the safety and effectiveness of current screening methods. This includes the “P.S.A.” test discovered forty years ago by Dr. Richard Ablin of the University of Arizona college of Medicine. Dr. Ablin noted that he never dreamed his identification of P.S.A. “would lead to such a profit-driven public health disaster. The medical community must confront reality and stop the inappropriate use of P.S.A. screening. Doing so would save billions of dollars and rescue millions for men from unnecessary, debilitation treatments.”
The U.S. Preventive Services Task Force essentially agrees with Dr. Ablin. After a careful review of the scientific evidence, the USPSTF made the following recommendation. “Current evidence is insufficient to assess the balance of benefits and harms of screening for prostate cancer in men younger than age 75 years (I statement). Do not screen for prostate cancer in men age 75 years or older (Grade D recommendation). “ Ann Intern Med. 2008;149:185-191. So, for those under 75 years of age, there is no clear benefit over the potential harm and, for those 75 and older, screening is not recommended. The following is a link to the full text of that clinical guideline.
Dr. Ablin is quoted as saying, "Thus, while a biopsy can diagnose prostate cancer, we cannot distinguish which cancer is the 'turtle' and which is the 'rabbit,' i.e., the killer, and needs treatment. Although it is frequently stated 1 in 6 men will get prostate cancer, a little appreciated fact is more men die with prostate cancer than from it."
"The health care system, and specifically therein, the urological community, can be financially more responsible by being far more conservative in administering screening tests (i.e., only for those with a family history of prostate cancer, those with symptoms, or other high-risk groups), by limiting prostate biopsies and by being more judicious when and which, if any treatment(s), is appropriate."
It is not surprising that some of the strongest advocates for the use of screening tests and biopsies are those with a financial interest in these procedures. This view is, in part, reflected in the 2009 abstracts below. There are some randomized controlled clinical trials underway that may provide a clearer picture of the value of prostate cancer screening. In the mean time, the safest path for chiropractors is to be a source of unbiased and balanced information and permit the patient to make an informed decision.
Risk of developing prostate cancer in the future: overview of prognostic biomarkers.Urology. 2009 May;73(5 Suppl):S21-7.
Fleshner NE, Lawrentschuk N.
Division of Urology, University Health Network, Toronto, Ontario, Canada. neil.fleshner@utoronto.ca
In many disease states, the use of biomarkers is a standard method of determining both the presence and the risk of the future development of disease. For several years, total prostate-specific antigen (PSA) levels have been the standard measure for the
diagnosis of prostate cancer (PCa) and other prostatic diseases. However, recent data have indicated that PSA can also be used to determine the risk of developing PCa in the future. This evolving use of PSA is supported by clinical trial data from the Baltimore Longitudinal Study of Aging, the European Randomized Study of Screening for Prostate Cancer, and the Malmö Preventive Medicine Study. Data from the European Randomized Study of Screening for Prostate Cancer have demonstrated that men with a PSA level of > or =1.5 ng/mL are at a significantly elevated risk of developing PCa compared with patients with a PSA level <1.5 ng/mL. The Malmö study showed that the PSA level could independently the predict cancer risk as far as 25-30 years into the future. Secondary nonserum risk factors (eg, age, family history, ethnicity) can also offer predictive value for determining the risk of developing future disease. Furthermore, recent investigations of novel biomarkers have yielded promising PCa prognostic candidates, including the PCa gene 3 and early PCa antigen 2. However, PSA remains the most reliable measure in assessing the risk of developing PCa.
Critical appraisal of prostate-specific antigen in prostate cancer screening: 20 years later.
Urology. 2009 May;73(5 Suppl):S11-20.
Pienta KJ.
Department of Internal Medicine, University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan 48109, USA. kpienta@umich.edu
Prostate-specific antigen (PSA) is secreted by all types of prostate epithelial cells and has been used for 2 decades as a biologic marker for prostate cancer (PCa). Since the implementation of PSA screening in the United States, the detection of PCa has increased, accompanied by a decrease in the
incidence of high-grade cancer and PCa-specific mortality rates. It has been suggested that these decreases have resulted from the enhanced detection of PCa while still curable. These data have been the impetus for early detection programs, which have recommended the initiation of screening as early as 40 years of age. Despite widespread use, PSA screening remains controversial, principally because of the lack of evidence from randomized controlled trials demonstrating a mortality benefit that could outweigh the concerns of the costs of overdiagnosis and overtreatment. Two ongoing, randomized controlled trials are examining whether screening reduces the risk of PCa-related mortality, and the results of these studies are expected soon. Although it has its limitations, PSA still remains the best-studied marker for the detection of PCa.
Early prostate-specific antigen changes and the diagnosis and prognosis of prostate cancer.
Curr Opin Urol. 2009 May;19(3):221-6.
Botchorishvili G, Matikainen MP, Lilja H.
Department of Clinical Laboratories, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
PURPOSE OF REVIEW: To delineate how recent findings on prostate-specific antigen (PSA) can improve prediction of risk, detection, and prediction of clinical endpoints of prostate cancer (PCa).
RECENT FINDINGS: The widely used PSA cut-point of 4.0 ng/ml increasingly appears arbitrary, but no cut-point achieves both high
sensitivity and high specificity. The accuracy of detecting PCa can be increased by additional predictive factors and a combinations of markers. Evidence implies that a panel of kallikrein markers improves the
specificity and reduces costs by eliminating unnecessary biopsies. Large, population-based studies have provided evidence that PSA can be used to predict PCa risk many years in advance, improve treatment selection and patient care, and predict the risk of complications and disease recurrence. However, definitive evidence is currently lacking as to whether PSA screening lowers PCa -specific mortality.
SUMMARY: PSA is still the main tool for early detection, risk stratification, and monitoring of PCa. However, PSA values are affected by many technical and biological factors. Instead of using a fixed PSA cut-point, using statistical prediction models and considering the integration additional markers may be able to improve and individualize PCa
diagnostics. A single PSA measurement at early middle age can predict risk of advanced PCa decades in advance and stratify patients for intensity of subsequent screening.