Why does today’s release of updated breast screening guidelines by the Canadian Task Force on Preventive Health Care (CTFPHC) bring to mind Yogi Berra’s famous quip , “It’s déjà vu all over again”? Because the new recommendations remind me of similar guidelines, put forward in 2009 by the United States Preventive Service Task Force (USPSTF), that laid a giant egg.

Having long been sold on the need for yearly mammograms, American women were caught off guard when the USPSTF panel recommended changing to biannual, rather than yearly, mammograms, starting at age 50, for those at average risk for developing breast cancer. In panning the recommendation against routine screening for women under 50, critics quickly pointed to a National Cancer Institute-sponsored multi-centre study which showed that, compared to women aged 40 to 49 who had annual mammograms, those in the same age group who had biannual mammograms had a 7 per cent higher risk of being diagnosed with late-stage breast cancer.

Stung by Republican accusations of medical “death panels”, and fearing voter backlash in the 2010 mid-term elections, the Obama administration quickly distanced itself from the report, effectively rendering it DOA. (Caught in the political crossfire was the agency’s already-completed study recommending against PSA screening for prostate cancer, which it delayed publishing for two years, until September, 2011).

With that background, what should we make of the newly-revised CTFPHC breast screening guidelines, published in this week’s issue of the Canadian Medical Association Journal, that recommend:

• cutting back on the frequency of screening mammograms from every 2 years to “every 2 to 3 years” in women ages 50 - 74
• no routine mammograms in women ages 40 - 49
• no MR (magnetic resonance) imaging for breast screening
• no breast self-examination
• no routine clinical breast examinations, alone, or in conjunction with screening mammograms

At this juncture, it is important to understand that the age-dependent recommendations for mammography (breast cancer is mainly, although by no means exclusively, a disease of women over 50) are meant for those at average risk for developing breast cancer. They do not apply to women of any age with identifiable risk factors, such as previous abnormalities on a mammogram, or a strong family history of the disease. Moreover, after consulting their physician, many individuals without identifiable risk factors may choose to ignore the guidelines, opting for yearly mammograms outside a provincially-run breast screening program.

In reaching its conclusions, the CTFPHC panel reviewed all of the pertinent medical literature (including the ill-fated USPSTF guidelines), tabulating the benefits (reduced mortality from breast cancer) and harms (e.g. false-positive mammograms, unnecessary biopsies, fear and anxiety caused by false-positive findings) of breast screening, including breast self-examination and breast examination by a doctor, in the various age groups.

They then used an evaluation algorithm (known by the acronym GRADE) to arrive at their recommendations. The results?

Surprisingly, every one of the panel’s recommendations, listed above, came under the category “weak”, meaning (in the words of the authors of the report) that, “the desirable effects probably outweigh the undesirable effects (weak recommendation for an intervention) or undesirable effects probably outweigh the desirable effects (weak recommendation against an intervention) but appreciable uncertainty exists [my italics]…. Weak recommendations result when the balance between desirable and undesirable effects is small, the quality of evidence is lower, and there is more variability in the values and preferences of patients.”

This begs the obvious question: if, in every instance, appreciable uncertainty exists and the quality of evidence is less than high (reaching down as far as “low” and, in one case, “absent”), what is the point in making any of these recommendations?

My opinion: unless, and until, new “strong” recommendations, based on “high-quality” evidence, are forthcoming, stick with current Canadian breast screening guidelines (including the option of regular mammograms under age 50) and continue to perform regular breast self-examination, or ask your doctor to do it during your routine physical.