Risks for Mammograms? Should All Women be Advised for this Screening?
There was some recent discussion on EmpowHer (Never Been "Mammogrammed") regarding the automatic advice of medical community to routinely prescribe mammograms as a harmful practice. Surprised? There is much discussion and advocacy related to mammograms, that it seems as it is the norm and the risks are not discussed...or even mentioned.
Are there risks to routine mammography? A few people think so, and after my literature review, I wanted to share these risks openly so that you can feel you have all of the information to make an informed decision about your health.
As I mentioned, the EmpowHer discussion regarding mammography risk is not unfounded, as a research study (NEJM Ten-Year Risk of False Positive) found that up to one-third of women screened (mammogram) received abnormal test results that required additional evaluation, and no breast cancer was present. (Please note: this study was conducted 11 years ago, and technology has come a long way since this time...it is just still on women's minds.
So, what are the risks and benefits of mammograms?
RISKS
- False Negatives*
- False Positives^
- Overdiagnosis and overtreatment
- Pain and anxiety of screening
- Anxiety and stress after screening for results and follow-up
BENEFITS
- Detects breast cancers earlier than other methods (symptomatically, manually, clinically)
- Mammography-detected cancers tend to have better prognoses
- Increase in breast cancer survival
As with any medical screening, evaluation or treatment, it is important to know all the facts about the specific treatment...but also important is to learn about the facility, doctors, technicians and health professionals themselves.
Here are some statistics on mammograms (for the US):
- Mammograms have a false positive rate of about 10% (average)
- Mammograms have a false negative rate of about 20% (average)
Notice that these are averages...and you can actually increase your odds of receiving an accurate result with a little homework! According to an article last year in US News and World Report (Avoiding a False Positive on Your Mammogram, there are several proactive measures you can take to ensure your facility is a "top performer" (a "top performer" was listed as a facility with a false positive rate of only 8%):
1. The facility is dedicated only to breast screening
2. A breast imaging specialist is on staff
3. Radiologists don't perform "double readings"
4. Quality assurance audits (machines and staff) are conducted 2 or more time annually
Beyond this, what is most crucial to know: your personal health risks. Some lifestyle behaviors (such as being overweight or sedentary) can increase your risk. Family history of breast cancer is important, too. It is estimated that about 5%-10% of breast cancer is thought to be hereditary, and this risk is "higher among women whose close blood relatives have breast cancer". In fact, "having one first-degree relative (mother, sister, daughter) with breast cancer can double a woman's risk. Having 2 first-degree relatives increases her risk 5-fold." (Source: What are the risk factors for breast cancer?.
Other important information to know about mammography (Mayo Clinic):
- False positive: If you do receive a positive result: "...most abnormal findings are not cancer."
- False negative: "a cancer may be too small or in an area difficult to be viewed by mammography."
For information on breast cancer screening guidelines (Mayo Clinic) (click on orange hyperlink).
Definitions:
* False Negative: a result that shows negative or normal, but failed to find an abnormality that is present.
^ False Positive: a result that is shows positive for abnormalities, when there is no condition present; the test should read "normal".
What are your thoughts about mammography, after reading this information? Does a false positive (and the implication of receiving unwarranted medical treatment, along with its anxiety, pain and/or recovery) change your mind? Does a false negative create doubt in "going through the trouble" of getting this screening?
I wanted to create an open discussion about this topic, and I personally hope that the minuscule numbers of about 10% rate for any-type of false result will not be your "excuse" to opt-out of this potentially life-saving screening method! You can read about people who are "against" the medical establishment as a whole, and you can also read about women whose lives were saved from their early detection of breast cancer. You can decide what is best for your own health!
My last question for discussion: do most women know that medical screenings, tests, evaluations and treatments are not 100% guaranteed accurate? This is common sense, right? Why are we expecting anything different with a mammogram?
Sources:
http://www.nlm.nih.gov/medlineplus/mammography.html
http://content.nejm.org/cgi/content/abstract/338/16/1089
http://www.breastcancer.org/symptoms/testing/new_research/20070411b.jsp
http://www.cancer.org/docroot/NWS/content/NWS_1_1x_False-Positive_Mammog...
http://jnci.oxfordjournals.org/cgi/content/abstract/97/16/1195
http://www.nlm.nih.gov/medlineplus/news/fullstory_86677.html
Add A New Comment6 Comments
Some relevant information about this subject has recently been published in the BMJ (formerly British Medical Journal) - see http://www.bmj.com/cgi/content/full/339/jul09_1/b2587 - be sure to read the responses to the article, particularly "Breast Cancer Overdiagnosis May Increase All-Cause Mortality ". The articles demonstrate an overdiagnosis rate of about 50%, showing that huge numbers of women are treated for breast cancer when they actually had a harmless, benign condition. The response cited above comments on the possible reasons that cancer screening has never been shown to save lives - not one single study has ever shown an overall mortality benefit. Cancer treatment is grueling and can shorten life, and because so many people are treated needlessly there is no mortality benefit to screening. Please consider this when you write about "lifesaving benefits" - there ARE NO lifesaving benefits, difficult as this may be to comprehend. And please, if you have been treated for cancer found via mammography, realize that you may not have needed treatment at all, and it is simply not possible to say whose life was saved and who was treated when they shouldn't have been. All survivors are told how lucky they were that their cancer was found - we now know that this may not be true at all.
Interesting! I do see your point, and had not thought about routine screenings in this way before...thanks for this new perspective.
My thought still is: this screening can DETECT cancers and tumors early. I understand you are saying that some tumors may not need to be detected (some regress on their own and do not need treatment). However, some breast cancer DOES need treatment, and mammograms DO detect tumors earlier than any other method. Early detection is key in survival rates.
I understand your logic, but here are some helpful statistics from the CDC:
- "In the United States, incidence of breast cancer has decreased significantly by 2.2% per year from 1999 to 2005 among women."
- "In the United States, deaths from breast cancer have decreased significantly by 1.8% per year from 1998 to 2005 among women."
Your point about the mortality will likely be that due to overtreatment, it makes sense there are less deaths from breast cancer. But, overall, isn't this a good thing?
I'm curious about the "overtreatment"-- without either of us going to extremes to prove our point. We can agree there is likely overtreatment for false positives. Do you have research that says what type of "overtreatment" this includes? Are we talking about a few more doctors office visits, an extra non-invasive test?f I believe you pointed out that some women will lose their entire breast when medically unnecessary...can you show me where this is proven (I find it difficult to believe). How many overtreatments are invasive and severe, vs. non-invasive and merely inconvenient? (and, we can both agree they can be stressful...a range of "concerning" to "psychological distress", dependent on the treatment received).
Just the mere fact of receiving a false positive, again, most women know this is the reality of our current medical system, does not warrant a clear cut case for me to stop the advice for women to receive mammograms that could potentially be beneficial. Abnormal test results can be a "norm", and the implications are thoroughly discussed by any reputable doctor with their patient (primarily that most abnormal results are benign).
thanks for the discussion
Great article about this in the Los Angeles Times. We have to come around to the idea that screening mammography often turns perfectly healthy women into cancer patients, and that women lose their breasts and endure toxic treatments for nothing all the time. Yes, it does happen. Please see: http://www.latimes.com/features/health/la-he-breast-overdiagnosis17-2009...
The problem with mammography is not false positives - it's that there is no way to tell if the tiny abnormalities discovered by mammograms (and confirmed with additional tests, including biopsies) are deadly cancer that will spread and kill a woman or if they are completely harmless. Yes, deadly cancer and completely harmless abnormalities look exactly the same in every way, even under a microscope. And yes, women lose all or part of a breast, and go through radiation and chemotherapy for completley harmless conditions all the time.
There's just no way to tell which abnormalities are deadly, so all of them are treated. The situation is this: for every woman whose life is saved, about 10 women are treated needlessly. Please see www.screening.dk for more information, and please read the part where the scientists detail their sources - it's all in the pamphlet. This is hard data, not speculation - overdiagnosis is real, and women lose their breasts and health needlessly all the time.
Mammography was urged on an entire population of healthy women without proper evidence that its benefits outweigh the risks. One organization that does a good job explaining the benefits and harms of screening mammography is the National Breast Cancer Coalition. Please see their well-reasoned, responsible position statement here: http://www.stopbreastcancer.org/index.php?option=com_content&task=view&i...
This was very helpful information. I understand the difference, and would love more explanation between the risks and benefits of diagnostic mammograms versus screening mammograms. It sounds like you are saying screening mammograms for all healthy women is unfounded, as when a lump is found it is treated as cancerous...whether it is or not. Diagnostic mammograms should be the focus, for women who have specific symptoms or other risk factors. I see the difference, but need to review some of the literature again, as something tells me there is a piece of information missing in all of this. There must be a large group of "healthy" women with no prior family history of breast cancer that a screening mammogram is beneficial for; however, I see your point that these women are being treated needlessly.
I do not understand how a screening mammogram would lead to a woman losing her breast? Wouldn't a diagnostic mammogram then be performed? A biopsy to test for cancerous cells? Isn't there a "waiting period" to see if the cancerous cells shrink or spread?
As your resource (NBCC) states on their site:
"...a woman's decision to undergo a screening mammogram must be made on an individual level, based on quality information about her specific risk factors, and her personal preferences. Women who have symptoms of breast cancer such as a lump, pain or nipple discharge should seek a diagnostic mammogram. Ultimately, resources must be devoted to finding effective preventions and treatments for breast cancer and tools that detect breast cancer truly early."
From my understanding, many cancers are asymptomatic, so waiting for a symptom means that it is not being caught in an early, more treatable, stage.