38. Thermography: Don’t Believe the Hype

Women sometimes ask about thermography and why we do not offer thermography as an alternative to mammography. Bottom line…. there is no evidence showing that thermography is a reliable replacement for mammograms when screening for breast cancer. 

What is thermography?

Thermography is a test that uses digital infrared thermal imaging (DITI). This type of imaging does not use radiation like mammography, which uses low-dose x-rays to image the breast. Radiation exposure in screening mammography is discussed in this article.

The thermogram provides a pictorial representation of temperature differences on the surface of the breast. Cancer needs an increased blood supply to grow. When blood flow increases to the cancer, the temperature around it rises. Therefore, the supporters of thermography believe that if you find areas of increased temperature, you can find a growing cancer in the breast.

In theory it is understandable why some patients think this sounds like a great alternative to mammography as a breast cancer screening tool without the use of radiation. Unfortunately, the available scientific literature doesn’t support the claims that thermography is a reliable screening tool to detect breast cancer.

1. This early study was published comparing mammography, clinical exam, and thermography. Even given the outdated mammography equipment used in this study (there have been many advancements in mammography since this study was published including digital mammography and 3D tomosynthesis), mammography outperforms thermography alone, physical exam alone, and thermography and physical exam combined.
   1. Mammography detected 78% of cancers compared with 39% detected by thermography.
   2. Not only did thermography not detect as many cancers, it also had a high false positive rate of ~30%. This means that 30% of people who were tested with thermography had abnormal test results but do not have breast cancer.
   3. Thermography did particularly poorly with the non-invasive form of cancer, ductal carcinoma in situ (DCIS). This is the type of cancer that is confined to the milk ducts but hasn’t invaded the surrounding tissues. If DCIS is found on imaging and completely removed surgically, it is the most treatable form of all breast cancers. Of all the imaging techniques currently available (including ultrasound and MRI), DCIS is best seen on mammography.
2. This study in 2016 also showed that mammography is more accurate in diagnosing breast cancer than thermography. Additionally, as part of this study a literature review regarding the effectiveness of DITI in an imaging program showed a wide variation in the effectiveness of diagnosing breast cancer. The authors concluded that there is insufficient evidence to recommend the use of thermography for breast cancer screening.
3. The FDA DOES NOT support the use of thermography as a stand-alone screening tool to detect breast cancer.
   1. Thermography has only been cleared by the FDA as an adjunct screening tool. This means that the FDA only supports the use of thermography to be used in addition to other breast cancer screening tools, with the current gold standard being mammography.
   2. In April 2017, the FDA sent out warning letters to multiple companies that fraudulently claim to prevent, diagnose, treat or cure cancer. One of those companies was Nature’s Treasures, Inc., a company that markets thermography for breast cancer detection.
   3. Legally thermography cannot be advertised as a substitute for mammography or be promoted as a stand-alone diagnostic imaging tool to detect breast cancer.
   4. The FDA has cleared thermography to be used as an additional tool for detecting breast cancer.
4. The American Cancer Society (ACS), the American College of Radiology (ACR), and the American College of Obstetricians and Gynecologists (ACOG) do not recommend thermography for breast cancer detection.  An in-depth discussion of breast cancer screening guidelines is outlined in this article.
5. United Health Care states the following concerning Medicare coverage of thermography: “There is insufficient evidence to conclude that thermography has a beneficial impact on health outcomes. The available evidence is limited and weak, and standards for image evaluation and cut-off values that would allow clinical recommendations based on this technology have not been established.”

The breast radiologist’s job is to detect breast cancer at its earliest stages when it is most treatable. Having sufficient data showing that the imaging technique(s) we use are the best available for the detection of breast cancer is absolutely necessary.  Based on the current evidence screening mammography remains the gold standard for the early detection of breast cancer.