Wednesday, January 26, 2011

USPSTF Breast Screening Guidelines Pushback

Updated 3/2017-- all links removed as many are no longer active and it was easier than checking each one.

The question continues as to when breast screening should begin.  The current pushback comes from radiologists Dr. Mark Helvie of the University of Michigan Health System and colleague Dr. Edward Hendrick of the University of Colorado.
The two researchers have published an article (full reference below) in the February issue of the American Journal of Roentgenology questioning the U.S. advisory panel’s breast cancer screening guidelines and suggesting the panel ignored scientific evidence that more frequent mammograms save lives.
For the article, the two conducted a review of the risk models used by the U.S. Preventive Services Task Force (USPSTF) to issue controversial breast screening guidelines in 2009.  They used Cancer Intervention and Surveillance Modeling Network modeling to compare lives saved by different screening scenarios and the summary of evidence prepared for the USPSTF to estimate the frequency of harms of screening mammography by age.
As a reminder, the USPSTF 2009 breast screening guidelines recommend:
  • The USPSTF recommends biennial screening mammography for women aged 50 to 74 years.  (Grade: B recommendation)
  • The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.  (Grade: C recommendation)
  • The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older. (Grade: I Statement)
  • The USPSTF recommends against teaching breast self-examination (BSE). (Grade: D recommendation)
  • The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of clinical breast examination (CBE) beyond screening mammography in women 40 years or older.  (Grade: I Statement)
  • The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of either digital mammography or magnetic resonance imaging (MRI) instead of film mammography as screening modalities for breast cancer. (Grade: I Statement)
Helvie and Hendrick analysis found that having annual mammograms from age 40 saved 64,889 more lives with the current 65% compliance rate.
They found that getting a yearly mammogram from age 40 cut a woman’s risk of fatal breast cancer by 71% versus the 23% reduction for women who followed the USPSTF recommendations.
The two researchers state, “The potential harms of a screening examination in women 40–49 years old, on average, consist of the risk of a recall for diagnostic workup every 12 years, a negative biopsy every 149 years, a missed breast cancer every 1,000 years, and a fatal radiation-induced breast cancer every 76,000–97,000 years.”
The two researchers feel the advantages of yearly mammograms starting at age 40 years outweighs the potential harms of screening.
I think perhaps they should read Dr. Marya Zilberberg’s, Healthcare, etc, post:  Why medical testing is never a simple decision
……..So, going back to the 10,000 women we are screening, of 9,900 who do NOT have cancer (remember that only 100 can have a true cancer), 10%, or 990 individuals, will still be diagnosed as having cancer. So, tallying up all of the positive mammograms, we are now faced with 1,070 women diagnosed with breast cancer. But of course, of these women only 80 actually have the cancer, so what's the deal?  ……….

Related posts:
Screening Mammogram Recommendations (January 7, 2010)
The New Mammogram Guidelines - What You Need to Know (December 27, 2009; TBTAM)

Hendrick, R. Edward, Helvie, Mark A.; United States Preventive Services Task Force Screening Mammography Recommendations: Science Ignored; Am. J. Roentgenol. 2011 196: W112-116


Anonymous said...

Decades of randomized controlled trials have shown that screening mammography reduces breast cancer mortality. These strict trials actually significantly underestimate the efficacy of screening mammography.

Unnecessary testing is bad. But the quote about medical decision making is so severely flawed in its description of how mammography works that it is misleading. To even compare a screening mammogram, a simple extremely low risk test designed to detect early breast cancer, to a non-indicated CT angiogram ordered in the ER is quite a stretch.

Mammography works by detecting small early stage cancers. In order to detect cancers when small and subtle additional imaging, and sometimes biopsy, is performed on a certain percentage of things that do not turn out to be cancers. If only obvious cancers are imaged and biopsied, and the smaller more subtle findings are ignored, the benefit of mammography is lost because obvious tumors are already large and higher stage and will carry a worse prognosis.

The idea of screening mammography is to find very early cancers that are likely to carry a favorable prognosis. This comes at the price of calling back about 10% of women for additional imaging. About 10% of these women (1% of those screened) will undergo biopsy. If you screen 1000 women, recall 100 women, and biopsy 10 women about 3-4 cancers will be diagnosed. The other women who get additional testing are not "diagnosed" with cancer as that quote states. Cancer is a pathologic diagnosis that requires biopsy and only 1% of women in screening will even undergo biopsy.

To better serve women's health we should be asking why fewer women are undergoing routine screening mammography today than 10 years ago. Compliance is down to 65%. I suspect misleading new reports which misinterpret extremely complex research are at least partly to blame as women are, understandably, quite confused right now.

In my opinion, the 2.5 million breast cancer survivors in the US right now, and the 260,000 who will be newly diagnosed this year alone, could use a break from all this nonsense.

Congratulations to Drs Hendrick and Helvie for their sane analysis of the USPSTF data. They are the people standing up against a tide of politics and misinformation in defense of a rational approach to women's health. Their work can ultimately save thousands of women's lives, if it is heeded.

rlbates said...

Anon, I'm not sure where you got the "compare a screening mammogram, a simple extremely low risk test designed to detect early breast cancer, to a non-indicated CT angiogram ordered in the ER is quite a stretch." Did you read all of Dr. Zilberberg’s post? Women who have false positive mammograms "pay" for it in un-necessary surgery and other tests.

Anonymous said...

All medical testing comes at a cost. What is described as unecessary testing (additional imaging and biopsies on women who end up not having cancer) is an essential component of screening mammography.

A certain percentage of false positive cases are necessary to reduce the number of false negative cases (missed cancers). I tried to explain why in my previous comment.

In countries where mammography is practiced as advocated by the USPSTF cancers are detected by screening mammography when they are larger and less treatable. This is an effective method to reduce the cost of the test, in dollars and otherwise. Fewer women have the inconvenience of a call back or benign biopsy. But it isn't as effective at saving women's lives.

Dr. Smak said...

Ramona, thanks for this post. Such a complicated issue for patients and physicians

Since the recent USPSTF recommendations I have begun recommending "1-2" year followup for my lower risk women. But I wonder how I, or my patient, will feel about those recommendations if I ever find a cancer on screening mammography that would have had a betterr outcome on an annual schedule.

Health, but especially breast cancer, is a very emotional issue. When rational guidelines are applied, as I believe they should be, things get so very complicated.