The Canadian Task force on Preventive Health Care has released their new PSA screening guidelines for the detection of prostate cancer in men. The guidelines do not support routine PSA screening for prostate cancer.
The Canadian Task Force on Preventive Health Care (www.canadiantaskforce.ca) is comprised of a panel of volunteers (either clinicians or methodologists) who review evidence and make recommendations to doctors. The guidelines for PSA screening tests were recently updated from prior recommendations made by the task force in 1994. In order to create the revised guidelines, the task force reviewed the recent clinical studies and outlined the main questions in regards to the effectiveness of PSA screening as a tool for prostate cancer prevention and treatment. Studies included in the analysis were those published between January 2007 and November 2012.
While the use of PSA screening can detect more cancers, it can also produce an increase in false positives, as an increase in the levels of PSA can be caused by urinary tract infections and benign prostatic hypertrophy (an enlargement of the prostate). In addition, PSA screening can also over diagnose cancer, meaning that even though cancer may be present, due to its slow progression, it may not necessarily cause the patient symptoms or result in death.
Taking into consideration the high risk of false positives and the detection of clinically irrelevant cancers, supported by the statistics of lifetime risk of prostate cancer being 14.3%, while the risk of death from prostate cancer is much lower at 3.6%. The harm versus benefit of PSA screening and subsequent potentially unnecessary treatment has to be weighed. Over diagnosis leads to unnecessary treatments that can cause side effects such as impotence, incontinence, infection, and bleeding
An important point to take into account is that during the review of clinical data, and creation of the guidelines, the task force did not take into consideration the cost of either PSA screening or prostate cancer treatment. Therefore cost-effectiveness was not a factor in deciding the harm versus the benefit of PSA screening.
The task force suggested that futures studies should be conducted to identify a suitable alternative screening test for prostate cancer, and conclude that the reviewed evidence does not support PSA screening as a method of reducing mortality from prostate cancer, however, it does increase the risk of harm from unnecessary treatment.
The summary of recommendations by the task force is as follows:
(The recommendations apply to all men without a previous diagnosis of prostate cancer).
- For men aged less than 55 years, we recommend not screening for prostate cancer with the prostate-specific antigen (PSA) test. (Strong recommendation; low-quality evidence.)
- For men aged 55–69 years, we recommend not screening for prostate cancer with the PSA test. (Weak recommendation; moderate-quality evidence.)
- For men 70 years of age and older, we recommend not screening for prostate cancer with the PSA test. (Strong recommendation; low-quality evidence.)
The recommendations are in line with other international recommendations, as summarised by the task force in Table 3 of the guidelines:
|Table 3: Summary of recommendations for PSA screening for prostate cancer from Canada and elsewhere (Source: “Recommendations on screening for prostate cancer with the prostate-specific antigen test” CMAJ October 27, 2014)|
|Organization||Age at initiation of PSA screening||Screening interval||Age at discontinuation of PSA screening|
|Canadian Task Force on Preventive Health Care (current)||Routine PSA screening not recommended|
|Canadian Task Force on the Periodic Health Examination (1994)11||Routine PSA screening not recommended as part of periodic health examination|
|US Preventive Services Task Force (2012)8||PSA screening not recommended; applies to men of all ages|
|Canadian Urological Association (2011)54||
||Not specified||75 yr|
|Canadian Cancer Society (2014)55||Men aged > 50 yr should talk with their doctor about whether they should be tested for prostate cancer||Not specified||Not specified|
|American Cancer Society (2012)56||Average risk: discussion at age 50 yr Increased risk: discussion at age 40 or 45 yr, depending on extent of risk||PSA < 2.5 ng/mL: 2 yr PSA ≥ 2.5 ng/mL: annual||Life expectancy < 10 yr|
|National Cancer Institute (2012)22||Insufficient evidence to determine whether screening with PSA or digital rectal examination reduces prostate cancer mortality|
|National Health Service (2013)57||No organized screening program; informed-choice program = men concerned about the risk of prostate cancer receive clear and balanced information about the advantages and disadvantages of PSA testing and cancer treatment|
|Prostate Cancer Canada (2013)58||
||Not specified||≥ 70 yr; decision should be based on individual factors (not specified)|
|American Urological Association (2013)59||
||≥ 2 yr||≥ 70 yr or life expectancy < 10–15 yr|
|American College of Physicians (2013)60||Men aged 50–69 yr: clinicians should discuss the limited benefits and substantial harms of screening for prostate cancer; they should not screen for prostate cancer with the PSA test in patients who do not express a clear preference for screening||Not specified||≥ 70 yr or life expectancy < 10–15 yr|
|Cancer Council Australia, Australian Health Ministers’ Advisory Council (2010)61||PSA test not suitable for population screening|
“Recommendations on screening for prostate cancer with the prostate-specific antigen test Canadian Task Force on Preventive Health Care” *First published October 27, 2014, doi: 10.1503/cmaj.140703 CMAJ October 27, 2014 cmaj.140703
Lesley Dunfield, Ali Usman, Donna Fitzpatrick-Lewis, Amanda Shane. “Screening for prostate cancer with prostate specific antigen (PSA) and treatment of early-stage or screen-detected prostate cancer: a systematic review of the clinical benefits and harms. Ottawa: Canadian Task Force on Preventive Health Care; 2013.” Available from: http://canadiantaskforce.ca/ctfphc-guidelines/2014-prostate-cancer/systematic-review/Last Accessed: Oct 30, 2014.
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Written by Deborah Tallarigo, PhD