Prostate cancer: should PSA screening be routine?

Prostate cancer is the most common cancer in American men behind skin cancer. There are expected to be 220,800 new cases diagnosed in the US this year. Although this number is high, death rates from prostate cancer are relatively low. Almost 100% of men diagnosed with the disease will survive 5 years or more - a rate many medical professionals attribute to prostate-specific antigen testing.

Many medical professionals believe the improvement in death rates from prostate cancer since the 1990s is down to the introduction of PSA testing.

The US Food And Drug Administration (FDA) first approved prostate-specific antigen (PSA) testing to screen asymptomatic men for prostate cancer in the early 1990s. In the decade prior to this approval, 5-year survival rates from the cancer stood at around 70-75%. By 1998, it had increased to 98.2%.

Although some health care experts have hailed PSA testing as the best available method to screen men for prostate cancer, there has been long-standing debate surrounding its use in routine testing.

PSA testing can lead to many false-positive results, meaning men can be alerted to cancers that are not actually present. Furthermore, critics argue that the test can lead to overdiagnosis, causing many men to undergo treatment they do not need.

September is National Prostate Cancer Awareness Month. In line with this campaign, we look at the evidence for and against PSA testing for prostate cancer and ask: should it be used for routine prostate cancer screening?

Questioning the accuracy of PSA testing

PSA is a substance made by cells in the prostate gland. During a PSA test, a clinician will take blood from the patient and send the sample off to a laboratory, where levels of PSA are measured by nanograms per milliliter (ng/mL).

High levels of PSA - usually 4.0 ng/mL or higher - can indicate the presence of prostate cancer, and a man with such levels is likely to need a biopsy to determine whether he has the cancer.

However, high PSA levels can also be a sign of less harmful conditions, such as prostatitis - inflammation or infection of the prostate gland - or enlarged prostate, a condition that can cause urination and bladder problems. Furthermore, the PSA test is unable to determine the difference between aggressive and benign prostate cancers. This is where concerns about the test's accuracy come into play.

Past research has estimated that between 17-50% of men diagnosed with prostate cancer through PSA testing have tumors that would not have resulted in symptoms throughout their lifetime.

This means many men may receive treatment for prostate cancer - such as surgery, radiation or hormone therapy - that they do not need, which can lead to serious side effects, including urinary incontinence and erectile dysfunction.

Recommendations against PSA testing met with criticism

Such factors have fueled recommendations against routine prostate cancer screening. In 2012, the US Preventive Services Task Force (USPSTF) led the way by issuing a recommendation against PSA-based screening for prostate cancer for men of all ages who do not have symptoms.

USPSTF co-chair Dr. Micheal Lefevre said of the recommendation:

"Prostate cancer is a serious health problem that affects thousands of men and their families. But before getting a PSA test, all men deserve to know what the science tells us about PSA screening: there is a very small potential benefit and significant potential harms.

We encourage clinicians to consider this evidence and not screen their patients with a PSA test unless the individual being screened understands what is known about PSA screening and makes the personal decision that even a small possibility of benefit outweighs the known risk of harms."

The move was met with much criticism. In a response published in the Annals of Internal Medicine, a group of prostate cancer experts stated that, given the fact that prostate cancer does not often present symptoms in its early stages, "eliminating reimbursement for PSA testing would take us back to an era when prostate cancer was often discovered at advanced and incurable stages."

This statement was echoed in another study by researchers from the University of Rochester Medical Center in New York, NY, which estimated that without routine PSA testing, an additional 17,000 men every year will likely be diagnosed with prostate cancer in its advanced stages.

Despite such criticism, other organizations - including the Centers for Disease Control and Prevention

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