Task Force says harms of PSA screening outweigh the benefits
Ottawa, 27 October, 2014–Today the Canadian Task Force on Preventive Health Care (CTFPHC) released an updated guideline on screening for prostate cancer using the prostate specific antigen (PSA) test. Based on the balance between the possible benefits and potential harms of early diagnosis and treatment of prostate cancer, the CTFPHC recommends not screening for prostate cancer with the PSA test. Guidelines are published in the Canadian Medical Association Journal (CMAJ).
“Unfortunately the PSA test is simply not an effective screening tool,” said Dr. Neil Bell, member of the Task Force and chair of the guideline working group. “Almost 20% of men aged 55 to 69 have at least one false-positive, approximately 17% of them will have unnecessary biopsies and over half of the detected cancers are overdiagnosed, which is the detection of cancers that would not have caused symptoms or death during the lifetime of the patient. False positives and overdiagnosis often lead to unnecessary treatments which can lead to impotence, incontinence, infections and other harms. Considering PSA screening results in only a 0.1% reduction in death from prostate cancer, the harms associated with screening outweigh the benefits for most people.”
Guideline development is based on a systematic review of available literature, a broad consultation process and scientific evidence synthesis. The development of the PSA screening recommendation was led by CTFPHC members, supported by a scientific staff, the Evidence Review and Synthesis Centre (ERSC) at McMaster University and various other external stakeholders. Recommendations of the guideline include:
- For men younger than 55 years of age and 70 years of age and older, CTFPHC strongly recommends against screening for prostate cancer with the PSA test. There is no evidence that screening with PSA tests reduces mortality, whereas there is evidence of harms.
- For men aged 55–69 years of age the CTFPHC does not recommend screening for prostate cancer with the PSA test. There is inconsistent evidence of small potential benefit of screening, and evidence of harms. This recommendation places a relatively low value on a small potential absolute decrease in prostate cancer mortality, and reflects concerns with false positives results, unnecessary biopsies, overdiagnosis of prostate cancer, and the harms associated with unnecessary treatments.
“We recognize that some men 55–69 may place a higher value on the small potential in reduction of death than on the higher risk of the undesirable consequences that come with PSA testing,” added Dr. James Dickinson, member of the Task Force and guideline working group. “Doctors should be prepared to candidly discuss all of the risks in comparison to the benefits, so that these patients can make informed decisions. We’ve developed patient education tools to help with this process.”
About Prostate Cancer
Most cases of diagnosed prostate cancer have a good prognosis and the ten-year estimated cancer survival rate is the highest of all cancers in men. This is likely due to improved treatment such as surgery, radiation and androgen deprivation therapy (ADT). Available clinical trial evidence indicates that, among men 55–69 who did not get screened, the risk of dying from prostate cancer after 13 years was 6 in 1,000. With regular PSA screening, the risk of dying from prostate cancer may be reduced to 5 in 1,000.
By comparison, evidence of the harms associated with screening found in the studies, for men with or without prostate cancer, include:
- 17.8% of men age 55 to 69 who were screened at least once had one or more false positives during three rounds of screening
- 17.8% of men screened using PSA testing (3 ng/mL) will have an unnecessary biopsy due to false positives which can lead to blood in the urine, rectum or semen as well as infection, hospitalization and even death
- 40–56% of all men diagnosed with cancer are overdiagnosed: that is cancer that would not have caused symptoms or death during the lifetime of the patient, but finding it leads to unnecessary treatments
Evidence of the harms associated with subsequent treatment for prostate cancer identified in the studies include:
- 11.4%–21.4% of men treated will have short-term complications such as infections, additional surgeries and blood transfusion
- 12.7%–44.2% of men will experience long-term erectile dysfunction
- Up to 17.8% of men will experience urinary incontinence
*0.4%–0.5% of men treated will die from complications of prostate cancer treatments
For the complete report and details of the recommendations, please visit our guideline.
About the Canadian Task Force on Preventive Health Care
The Canadian Task Force on Preventive Health Care has been established to develop clinical practice guidelines that support primary care providers in delivering preventive health care. The mandate of the Task Force is to develop and disseminate clinical practice guidelines for primary and preventive care, based on systematic analysis of scientific evidence.