Lowering PSA threshold could increase overtreatment of prostate cancer

A large proportion of low-risk prostate cancer patients seek aggressive treatment. Lowering the threshold at which prostate-specific antigen screenings are considered normal would raise those numbers, according to a new study.

Researchers at the Cancer Institute of New Jersey in New Brunswick said the result may increase the risk of overdiagnosis and overtreatment of the disease. They reviewed data from the Surveillance, Epidemiology and End Results database on 123,934 men, age 25 and older, with newly diagnosed prostate cancer from 2004 to 2006.

They found that 75% of men with PSA levels below the normal 4.0 ng/mL and low-risk prostate cancer received aggressive treatment such as radical prostatectomy or radiation therapy.

Men whose cancer was detected through screening were about 1.5 times more likely to seek aggressive treatment, according to the study published in the July 26 issue of the Archives of Internal Medicine (link).

"It is clear from our current study that men are choosing aggressive forms of treatment when they may not need to," according to a statement by senior study author Grace Lu-Yao, PhD, MPH, cancer epidemiologist and associate professor at the University of Medicine & Dentistry of New Jersey.

Debate over the benefits of PSA screening is ongoing as researchers continue to investigate basic questions such as who is being diagnosed with prostate cancer, how are they being treated and which patients benefit most from different treatments, said study co-author Mark Stein, MD, assistant professor of medicine at the Cancer Institute of New Jersey, which is part of the university.

"Just trying to understand treatment patterns is very important," he said.

Some have suggested lowering the normal PSA level from 4.0 ng/mL to 2.5 ng/mL. A 2005 study estimated that the move would double the number of abnormal PSA scores to 6 million annually. "If all those men chose to be treated, that would be a substantial burden on our health care system," Dr. Stein said.

The study highlights the importance of physicians counseling patients about the benefits and risks associated with treatments. "Patients have a large say in how their treatments are ultimately decided," Dr. Stein said.

It can be difficult to explain to patients that they have cancer but may not need treatment. Some aggressive cancers have been found in patients with normal PSA levels. "To say you have cancer and we're not going to do anything about that, that is a difficult discussion to have," Dr. Stein said.

The findings demonstrate that the PSA level doesn't provide sufficient information for the basis of treatment and the need for researchers to find a better way to identify how aggressive a cancer is, the study said.