Prostate cancer is a slow-growing disease, and doctors are forever facing multiple barriers to discontinuing routine PSA screening. So, perhaps it is not surprising that consensus in the medical community on when to discontinue PSA screening is hard to achieve. Put simply, doctors are unable to agree completely when an old man should no longer be screened for prostate cancer.

PSA stands for Prostate-specific antigen, it is a protein the prostate gland uses. Most of men’s PSA leaves the body in semen. However, a small amount escapes into the blood stream. The PSA test is a blood test based on monoclonal antibody technology. The test measures PSA blood levels. If levels are high, or rise over a specific period, it could mean that the patient might have developed prostate cancer.

Medical practice guidelines for prostate cancer screening, or PSA screening are controversial, because there is uncertainty about whether the benefits of screening outweigh the risks. The risks include overdiagnosis, unnecessary biopsies and other medical interventions.

According to a review by the Preventive Services Task Force, USA, “Prostate-specific antigen-based screening results in small or no reduction in prostate cancer-specific mortality and is associated with harms related to subsequent evaluation and treatments, some of which may be unnecessary.”

The FDA (Food and Drug Administration) has approved the PSA test for yearly screening of males over the age of 50. In the guidelines, the patient should be told about the risks and benefits associated with PSA screening beforehand. A PSA blood level of between 4 and 10 ng/mL (nanograms per milliliter) is considered “suspicious”, and a repeat test should be carried out. If the repeat tests shows a high PSA level, the doctor may consider a prostate biopsy (tissue is removed surgically and tested in the lab).

The UK National Health Service (NHS) does not recommend routine PSA testing. Rather, it allows the patient to decide for himself, based on what the doctor has recommended.

False-positives are common in PSA tests. 70% of all positive PSA tests (showing high PSA levels) occur in men without prostate cancer.

In the USA, a considerable number of males are diagnosed with prostate cancer early on, mainly through PSA tests. This may seem like a good thing – however, prostate cancer is slow growing and rarely progresses to become life-threatening. If a man is unlikely to die from an existing prostate cancer, treating and/or removing the tumor early may well do him more harm than good. Treatment carries many risks, including erectile dysfunction (male impotence) and urinary incontinece. That is why the US Preventive Service Task Force (USPSTF) has stopped recommending routine annual screening for men over 75.

For elderly patients, intervention is more likely to result in greater harms than benefits. As PSA levels rise with age anyway, and other prostate conditions occur as men get old, overdiagnosis and treatment is more common for this age-group.

Dr. Craig E. Pollack and team, from Johns Hopkins School of Medicine in Baltimore set out to determine how primary care doctors (GPs, general practitioners) handle the age question. Providers from a large, university-affiliated primary care practice were surveyed and asked about their screening practices, what influenced their decision to stop screening, and what barriers they could identify to discontinue screening.

141 healthcare providers took part in the survey. 59.3% of them took both life expectancy and the patient’s age into account, while 12.2% took neither factors into account when deciding to discontinue screening.

The study has been published in the journal Cancer.

The age at which screening stopped varied significantly among the providers. 66.4% of them said that assessing life expectancy was extremely difficult.

In an Abstract in the journal, the authors wrote:

“Taking patient age and life expectancy into account was not associated with provider characteristics or practice styles. The most frequently cited barriers to discontinuing PSA screening were patient expectation (74.4%) and time constraints (66.4%).”

Clinical uncertainty and time constraints tended to influence black providers less than non-black ones. The authors added that the number of black providers (doctors) in this survey was very small.

The authors concluded:

“Although age and life expectancy often figured prominently in decisions to use screening, providers faced multiple barriers to discontinuing routine PSA screening.”

Written by Christian Nordqvist