Detecting Breast Cancer: Mammography Vs Thermography
First of all, let me be clear that when I say I still “like” mammograms I am not saying that I “enjoy” mammograms.
Nobody relishes the idea of getting their breast squished between two cold plates of a giant machine.
I don’t feel nervous on my way to a mammogram because of the technique or method of doing the test, but for the same reason that any woman would feel nervous. I’m worried about the test finding a problem. The nervousness that accompanies the drive to the mammography center lasts all the way until the letter arrives with the results.
Even though my mother’s breast cancer was a long time ago and she’s doing great, and she also had negative testing for the gene, I still feel a little apprehensive every year.
In this blog, I will touch on the most recent recommendations for mammograms, and the emergence of thermography.
The idea of any screening test is that it detects a disease before the onset of symptoms, and also that the benefit of the test outweighs any harm the test can cause.
In the case of mammography, the intended benefit is the early detection of a breast cancer when it can be treated relatively easily and result in good long-term survival. (The word “cure” tends to never be used regarding cancer.)
Besides the physical discomforts of undergoing a mammogram, the possible harm of the mammogram comes from finding lesions that turn out not to be cancer, but which lead to further evaluation including more imaging and biopsies. This further evaluation also usually causes even more anxiety, pain and recovery time if surgery is done. Just getting called back in for more testing is scary!
Mammograms miss cancers about 10% of the time (false negatives), usually due to dense breast tissue. (Women with dense breast tissue often get the scare of being called back in for further evaluation.) About 7% of the time, mammograms detect lesions that get further testing done but turn out not to be cancer (false positive).
As screening tests go, these are not bad stats. For example, it is no longer clear that cholesterol screening, performed on nearly everyone, has any predictive value for cardiovascular disease1. While 100% is best, it’s pretty good when a test catches 90% of the disease it is supposed to catch, and that “only” 7% of women having it get further evaluation they turned out not to need.
The American College of Obstetricians and Gynecologists (ACOG) revised its recommendations as recently as 2017. ACOG recommends that women from ages 40 to 49 who are at average risk (no personal or family history of breast or other related cancers) for breast cancer be offered a mammogram, and that starting at age 50, have a mammogram every 1 to 2 years. After age 75, (the peak diagnosis of non-genetic breast cancer in the U.S. is around age 68) it again becomes an individualized decision between a woman and her doctor.2
In Europe and Canada, mammograms are recommended every 2 to 3 years from age 50 to 79. The American Cancer Society and the American College of Radiology recommend yearly mammograms starting at age 40. Meanwhile, a group called the Cochrane Collaboration is calling into question the entire practice of routine mammography for women. (While this group is ideally supposed to above politics, it is going through tough times at the time of this writing.3)
Anything with a temperature emits infrared radiation, which can be picked up with thermal imaging. The basis of thermography for cancer detection is that an area of cancer cells will have a higher temperature than the surrounding tissue.
This is because cancers tend to
- grow more blood vessels, giving them more blood flow;
- have higher metabolic rates than normal cells; and
- be associated with inflammation.
The appeal of thermography is that it uses no radiation and the camera does not touch the body (no squishing the breast = very appealing).
What I did not know before doing the research for this article, is that in order to perform a breast thermogram, a woman has to sit undressed from the waist up for about 15 minutes before the imaging in order for her skin to equilibrate to room temperature. Then, after the first set of images is taken, she has to do a “cold challenge” in which she puts her hands in cold water for 10 minutes, then the breast images are repeated. The temperature change patterns are captured on film then interpreted by someone trained in thermography.
Thermography has not gotten a good foothold in the world of conventional medicine mostly because of at least 2 large studies in the 1970’s that compared mammography with breast thermography. In one large study of 139 biopsy-proven breast cancers in 16,000 women, breast thermography detected cancer only 39% of the time, compared to 78% for mammography.4(In fact, in this study, clinical breast examination correctly detected the cancer 55% of the time, better than thermography.) In a review article from 2010, the author gives a pretty thorough summary of information about mammography vs. thermography, despite his extreme bias against thermography.5
Let’s remember that both mammography and thermography are screening tests, not tests that allow us to prevent a breast cancer from developing in the first place. The idea that “earlier is better” regarding breast cancer actually has some limits. Several studies now exist that confirm that some cases of early breast cancer, as seen on a mammogram, do not go on to grow and become invasive cancer, but instead can actually go away (our bodies clear out cancer cells all the time when there is a good cell environment and a healthy immune system).6
We also know that screening for breast cancer leads to detecting more cases of breast cancer, as well as some cases of overdiagnosis or even misdiagnosis.
At this time, breast thermography is FDA approved as an adjunct to mammography for the early detection of breast cancer, not as a stand-alone screening method. Obviously, computer technology has advanced unbelievably since the 1970’s. I hope there will be more studies comparing thermography (with updated technology) and mammography, so women can have more options for effective early detection of breast cancer.
I will definitely get a thermogram at some point, to see what it’s like and to compare the images with my mammogram results.
But for now, I will continue to get my annual screening mammogram, and I encourage women over 50 to get theirs too.
Please note: The material in these articles, provided by Dr. Liz Lyster, is designed to provide informative and current information as of the date of the posts. The articles should not be considered, nor are they intended to constitute medical advice. For information on your particular circumstances, please contact us.