Who would have thought a federal task force with an unpronounceable acronym for a name could stir up so much controversy with one journal article?
Like most physicians who care for women, I was a bit surprised by substantial changes in the US Preventive Services Task Force (USPSTF) screening recommendations for breast cancer released last week.
This past week, I read both the 2002 and 2009 reports, and the evidence reviews they are based on. Here's my take on the new recommendations. This is a longish discussion, so stay with me for a few minutes.
In general accord with the 2002 statement, most US physicians have been recommending mammograms every 1-2 years starting at age 40 and then annually from age 50. We consider clinical breast exams to be an important part of a woman's annual physical and encourage our patients to do regular self breast exams.
For women at average risk of developing breast cancer, the USPSTF now says the best current evidence supports mammograms every other year, starting at age 50 and possibly ending at age 74. The task force points out the usefulness of clinical breast exams has not been proven.
And, on the basis of two large studies, the report also states doing self breast exams does not lead to a lower risk of dying from breast cancer.
Mammogram screening benefits and harms
In making these recommendations, the task force calculated benefits and harms from breast cancer screening. The identified benefit was reduced risk of dying from breast cancer. The harms included false positive results leading to unnecessary further testing and overdiagnosis of non-life threatening cancers.
The task force based its mammogram recommendations on a review that estimated how many women in different age groups would have to have regular mammograms to prevent one woman's death from breast cancer.
For women in their 40s, one life is saved for every 1904 screened women. In comparison, one life is saved by screening 1339 women in their 50s and 377 women in their 60s. The benefit is obviously greatest for women in their 60s.
Here is the review's concluding paragraph:
Our meta-analysis of mammography screening trials indicates breast cancer mortality benefit for all age groups from 39 to 69 years, with insufficient data for older women. False-positive results are common in all age groups and lead to additional imaging and biopsies. Women aged 40 to 49 years experience the highest rate of additional imaging... Mammography screening at any age is a tradeoff of a continuum of benefits and harms. The ages at which this tradeoff becomes acceptable to individuals and society are not clearly resolved by the available evidence.
For physicians who regularly read the medical literature, the USPSTF statement does not come out of the blue. The effectiveness of screening tests in preventing cancer deaths is regularly addressed in journals we read.
After the report was released, most of the discussion has concerned mammograms not being automatically recommended for women in their 40s.
Screened women in that age group did have a 15% reduction in breast cancer mortality, which seems worthwhile to most physicians. However, women in their forties had significantly more false positives, leading to further imaging and, less often, biopsies.
The task force included anxiety with further testing as a harm from screening. Many women have spoken up to say they can deal with anxiety to gain a benefit from screening, and they think the task force report was condescending. Here's what the report said:
False-positive results are common with mammography and can cause anxiety and lead to additional imaging studies and invasive procedures (such as biopsy or fine-needle aspiration). False-positive results and accompanying additional imaging studies are more common in younger women... Anxiety, distress, and other psychosocial effects can exist with abnormal mammography results but fortunately are usually transient, and some research suggests that these effects are not a barrier to screening... Other potential harms, such as pain caused by the procedure, exist but are thought to have little effect on mammography use.
How the task force incorporated these concerns about anxiety and pain into their recommendations is not clear to me.
Another concern is that most of the data comes from outside the US, and may not accurately reflect our current mammography results and breast cancer treatment success.
Mammograms and breast biopsies are only as good as our ability to interpret their results. Some of the most exciting breast cancer research involves individualizing breast cancer treatment by identifying the biological behavior of a woman's specific cancer.
When and if individualized treatment is available, it will spare many women from being overtreated for breast cancer. This research could also save lives of women who have cancers that may require unusually aggressive treatment.
If we significantly back off from our screening programs, fewer women may benefit from these advances.
The review article acknowledges this:
Breast cancer is a continuum of entities, not just 1 disease that needs to be taken into account when considering screening and treatment options and when balancing benefits and harms. None of the screening trials consider breast cancer in this manner. As diagnostic and treatment experiences become more individualized and include patient preferences, it becomes even more difficult to characterize benefits and harms in a general way.
What to do now
So how will I incorporate the USPSTF report into my practice? The task force made recommendations for the general population, but in clinic, I make recommendations to individuals.
The first step is assess a woman's risk for developing breast cancer. In my clinic, I use the Gail model and any available information about a women's breast tissue density.
For now, I will make sure average-risk women in their 40s are aware that mammogram false-positives are higher for them than for older women. However I will also tell them having mammograms reduces their risk of dying from breast cancer and that today's evidence for and against screening is not the last word. Then we can make a shared decision about mammograms.
As the task force itself says:
The USPSTF recognizes that clinical or policy decisions involve more considerations than this body of evidence alone. Clinicians and policymakers should understand the evidence but individualize decision making to the specific patient or situation.
That's what I do now and will continue to do.
In a future post, I'll write about mammograms for women in their 50s and older, as well as clinical and self breast exams.
Terrific stuff! This is the type of stuff that should be spread around the web. Shame on the search engines for not positioning this post higher!
Posted by: Counseling Jacksonville | 09/14/2011 at 06:24 AM