Controversy has long existed over the benefit of the prostate specific antigen (PSA) test used to screen for the presence of prostate cancer, and there has been little study to document the risk profile of men who have a PSA level at or below what is considered 'normal.' New research published in the latest edition of Archives of Internal Medicine (Vol. 170, No. 14) by a team of investigators at The Cancer Institute of New Jersey (CINJ), further explores this population. The findings show that most men with prostate cancer who tested below the normal PSA level and had low-risk disease nevertheless underwent aggressive treatment. CINJ is a Center of Excellence of UMDNJ-Robert Wood Johnson Medical School.
PSA is a protein in the cells of the prostate gland which can be measured through the blood. Elevated levels of PSA can indicate the presence of prostate cancer as well as other prostate health conditions such as enlarged prostate, inflammation and infection. In the past, doctors often used an established guideline of 4.0 nanograms per milliliter (ng/mL) or more to determine whether a biopsy or other testing is necessary. In recent years some clinicians have chosen to initiate further testing (i.e. biopsy) even in patients with PSA scores below 4.0. This study, Risk Profiles and Treatment Patterns Among Men Diagnosed as Having Prostate Cancer and a Prostate Specific Antigen Level Below 4.0 ng/mL, takes a closer look at this population.
Using the population-based Surveillance, Epidemiology, and End Results (SEER) database, researchers reviewed information on various patient demographics, disease classification and treatment patterns from 123,934 men aged 25 and older with newly diagnosed prostate cancer from 2004 to 2006. All of the SEER registries hold the highest level of certification of data quality.
Investigators found that 14 percent of these men had PSA values lower than 4.0, and that these men were generally younger in age and had lower Gleason scores (a grading system to help determine prognosis in patients with prostate cancer). Of that number, 54 percent harbored low-risk disease (stage II or lower). Radical prostatectomy or radiation therapy was the treatment of choice for 75 percent of that group. According to the authors, despite their low risk of having clinically significant disease, treatment rates for these men were similar to those with PSA values of between 4.0 and 20.0. The study also found that 66 percent of men between 65 and 74 years old with low-risk disease and a PSA value of 4.0 or lower also opted for radiation therapy or radical prostatectomy.
It has been suggested that the PSA level for concern be reduced to 2.5 ng/mL. A 2005 study (Welch, HG, et. al.) in the Journal of the National Cancer Institute indicates that threshold reduction would double the amount of abnormal PSA results to approximately six-million. That, says senior author Grace Lu-Yao, PhD, MPH, cancer epidemiologist at CINJ and associate professor of medicine at UMDNJ-Robert Wood Johnson Medical School and of epidemiology at UMDNJ-School of Public Health, could result in even more men receiving unnecessary treatment. "Because the inability still exists to determine whether prostate cancers are slow growing or aggressive, lowering the PSA threshold might increase the risk of overdiagnosis, which could lead to treatment that holds no benefit for the patient or could have adverse side effects," she noted.
"It is clear from our current study that men are choosing aggressive forms of treatment when they may not need to. This is especially concerning for older men, as previous studies done by our team show excellent disease-specific survival for men with low-risk cancer following conservative management," said Dr. Lu-Yao. "Because this is the most comprehensive study of U.S. men in this population to date, we anticipate that these results will help both physicians and patients more closely examine a man's treatment needs."
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