Thermography for breast cancer screening: Where is the evidence?

Thermography uses heat sensitive infrared cameras to image the body and measure heat emission.

Solid tumors, even when they are tiny, have an increased blood flow and inflammation compared with non-cancerous tissue. Theoretically this could lead to a thermal gradient between a cancer and the surrounding non-cancerous tissues. Some animal studies indicate that thermography might detect heat differences between inflamed and non inflamed tissue and so it was postulated (initially back in the 70s) that thermography might be a potential screening tool for breast cancer. I remember going round the thermography barn (albeit for another diagnosis) in 1990 during a medical school elective in the U.K. The images were cool and there were lots of “oohs’ and “aahs” from patients, but I don’t remember it changing much.

But breast cancer screening without radiation! Sounds like a great idea! So, let’s look at the studies … except there are very few studies to look at. This is always a bit of a red flag, because If something is so truly amazing and such a game changer then typically everyone wants a piece of the action: doctors, researchers, universities, free-standing clinics, manufacturers, you name it, not just naturopathic or concierge clinics.

Trust me when I say that a new, radiation-free effective method of detecting breast cancer would be a game changer, so the lack of studies suggests the early data is just so poor that there is no point in going on (a bit like inventing a unicycle with a square wheel and then seeing everyone else whiz around on a round one).

For the record, there are two recent meta-analysis, both of which conclude there is no evidence to support the use of thermography either as a screening tool or a diagnostic tool for breast cancer. The highest quality prospective study that I found looked at thermography in women with breast symptoms and thermography was dismal. The positive predictive value, meaning the chance that a positive test meant cancer, was 25% for thermography versus 88% for ultrasound and 84% for mammography. Positive and negative predictive values were far better for ultrasound and mammography compared with thermography.

One positive study touted by proponents of thermography (Wishart et. al., EJSO 2010) still had weaker numbers than mammography and ultrasound, involved only 100 women (compared with the hundreds of thousands in mammography and ultrasound studies), and one of the authors has a major competing commercial interests as the co-founder of Infrared Sciences Corp (manufacturers of Sentinel BreastScan, a breast thermography machine) and left that company to develop software to interpret breast thermography.

There is absolutely no data to support thermography for breast cancer screening or as an aid for diagnosis. Health Canada has even issued a health advisory against breast thermography. It is illegal to advertise  or sell these machines in Canada to screen for breast cancer. The FDA has issued several warning letters  as promoting thermography for breast cancer screening is against the law in the United States.

At best thermography adds nothing to breast cancer screening or diagnosis and at worst it might lead women to seek biopsies because of false positive results or the even more worrisome false reassurance that they have been appropriately screened.

Why would a doctor recommend thermography? Either they haven’t read the literature on breast cancer screening or they are fleecing patients (financially and emotionally) into thinking they are getting “individualized,” “state of the art,” “natural” technology when in fact they are getting one of the oldest medicines in the book, snake oil.

Jennifer Gunter is an obstetrician-gynecologist and author of The Preemie Primer. She blogs at her self-titled site, Dr. Jen Gunter.

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