Thermography: Worse than useless

Earlier this spring, I described the Choosing Wisely campaign in the United States, an initiative designed to redirect resources away from medical treatments that are useless or harmful. In the spirit of the campaign, I suggested Five Things Pharmacists and Patients Should Question. My list included unvalidated IgG food intolerance blood tests like Hemocode, dubious “Body Chemistry Balancing”, inaccurate heel ultrasound bone density testing, and saliva hormone testing. I also singled out breast thermography as a particularly questionable test that pharmacies offer. Cancer tumours need a rich blood flow to grow, so cancer cells secrete chemicals to stimulate the development of new blood vessels. More blood flow means warmer tissue. Thermography, sometimes called digital infrared thermal imaging (DITI) uses infrared measurement to detect skin temperature differences. Thermography has emerged as an alternative therapy offered by naturopaths, homeopaths, and some health professionals, like pharmacists. Note the claims made:

  • Finlandia Pharmacy in Vancouver says thermography “can detect the first signs of cancer formation before any other diagnostic service currently in use”
  • Wisdom Thermography, offering services at Marks Pharmacy in Vancouver, claims with thermography, “abnormal heat signatures can be detected up to 10 years prior to tumour development”. They even add,

    So, if the recent Canadian Task Force on Preventative Health Recommendation has you feeling like your options are limited, then take Thermography into consideration as additional way to get an idea of what is going on in your body. Thermography has been found to be 90% accurate and, simply put, by adding this screening to breast exams and Mammograms the chances of early detection and survival are increased.

  •  Avita Integrative Health and pharmacy in Brampton claims, “thermography of the human breast can make a profound and positive impact on breast cancer and other breast disease.”

Perhaps not surprisingly none provide supporting evidence for these statements. That’s because the scientific evidence actually shows thermography isn’t a useful tool for screening or diagnosis. This evidence review on thermography [PDF] from the Canadian Agency for Drugs and Technologies in Health is a excellent summary from an unbiased, non-partisan source. The analysis, based on a comprehensive review of the evidence, notes that thermography is worse than mammography in terms of sensitivity, specificity, and predictive value. That is, it gives more false positives, leading to unnecessary worry and investigations, yet it misses actual cancer. The bottom line is that there is no persuasive evidence to show thermography has any value for screening or detecting cancer, either used on its own or in combination with mammography.

In light of the lack of evidence, Health Canada does not licence thermography in Canada, nor does it recommend its use as a screening technique. It notes,

“Claims that thermography is useful in diagnosing breast cancer have not been proven, and thermography equipment has not been licensed for breast cancer screening in Canada.”

CBC took thermography on this week, running several features on the practice, including this clip on The National, where this naturopath clinic is featured which claims thermography offers a “early detection program” for cancer. In response to CBC’s coverage of thermography, two provinces (to date) have already issued “cease and desist” letters to clinics offering thermography. Interviews with physicians identify that thermography is driving women to seek investigations when none are necessary:

Test is ‘actually useless’

Medical experts take issue with claims trumpeting the benefits of thermography in diagnosing breast disease. Nancy Wadden, a St. John’s doctor who chairs the mammography accreditation program of the Canadian Association of Radiologists, says women are paying big money for a test that is “actually useless.”  Wadden says that women who actually need treatment face longer wait times because of women who register false positives after thermography. “These women have a significant number of false positives, so then they are coming and they are clogging up my ultrasound list and my mammogram list and then displacing the people who really need to have the test, who are waiting there,” Wadden said. “Their length of time to get a diagnosis is prolonged, because we’ve got people who have had this useless test that has given a false positive result.”

Worse than useless. Harmful.

And just today, Health Canada has taken further action, issuing another advisory:

“Health Canada is not aware of any clinical evidence that thermography can be used effectively as a screening technique for the early detection of breast cancer” “As such, it may present a potential risk to women relying on the results.”

There is justified debate on the utility of mammograms for breast cancer screening. In particular, overscreening those at low risk of breast cancer appears to be harming more than it benefits. (This is not new, and has been a discussion point for several years here over at Science-Based Medicine where I also blog. David Gorski’s post this week gives a good summary of the controversy and the evidence.) Clearly driven by this vigorous debate on the merits of mammograms, thermography has emerged as an “alternative” treatment that is arguably worse than mammography by every measure.

Kudos to the CBC for their activism on thermography. Despite the lack of any credible evidence, and supported by a large network of naturopaths, homeopaths and even some pharmacists, thermography is widely available in Canada.  The bottom line with thermography is that it hurts and harms more than it helps. Regrettably, it seems that some pharmacies and other providers are either ignorant of the scientific evidence, or are simply indifferent to it.

About these ads

5 thoughts on “Thermography: Worse than useless

  1. It’s good to see that Canada is taking action–a lot stronger than the barely audible whimper we are getting from the FDA here.

    Women have enough to worry about with the imperfections of mammography, they don’t need thermography making things worse.

  2. What does this supposed to mean? “thermography of the human breast can make a profound and positive impact on breast cancer and other breast disease.” Sounds more like thermography is going to DO something TO breast cancer etc. as opposed to diagnosing its presence.

    Mammograms are pretty well useless too. The majority of breast cancers are self reported. The imaging studies tend towards detection of minor insignificant non malignant tumours resulting in major anxiety, needless invasive treatments, risk management chemo and radiation and the bogus claim that breast cancer deaths are decreasing. The death rate from true malignancies has not changed much since the early 1960s.

    The usefulness of a mammogram depends on a pair of eyeballs and a brain paying attention to the images. From what I know based on the experiences of my patients, it would appear that whoever reads the images just does a cursory check. Second opinion on the same images after patient self diagnosis due to pain indicated that the lesion was present and visible on the original mammogram.

    Technology can be excellent. A human being quickly scanning through dozens of images may not be.

    When patients tell me that they are insisting on a CT scan or an MRI,they have a belief in the technology. What they fail to realize is that there is a person who will look at the images. In the ‘olden days’ patients valued astute diagnosticians. Today the dependance has shifted to the wrong thing.

  3. What breathtaking hypocrisy! Ranting on about thermography while ignoring the the widely publicized shortcomings of mammography. This sort of behaviour insults the intelligence of the public. It is bad public policy and provides a huge PR boost to natural health advocates. Another blow to the credibility of Official Medicine. If the positions of this faction were sound why do resort to such tactics?

    Political Ottawa very well understands this. Time after time politicians have learned their constituents don’t trust, believe or like Health Canada. Sadly, you’re just preaching to the converted and your congregation keeps getting smaller.

    The shame is all this vitriol – from all sides – prevents consideration of much needed reforms in the regulation of NHPs.

    • Not hypocritical, a boost to “natural health” advocates, or a blow to the credibility of “Official medicine” at all: thermography has no use; mammography has some. Hard to criticize Scott for addressing the former so thoroughly, especially given that it is the title of his post, and even more so given he notes the “…justified debate on the utility of mammograms for breast cancer screening.”

      “their constituents don’t trust, believe or like Health Canada” Really? Evidence? Even then, science is not a popularity contest. And how does this somehow validate thermography?

      “preaching to the converted and your congregation keeps getting smaller”
      Evidence? And how does this somehow validate thermography?

      “The shame is all this vitriol – from all sides –…”
      This is concern trolling. It is impossible to qualify Scott’s post as “vitriol” just because one disagrees with the good evidence it presents and sound logic it employs.

      • Why see the splinter in your brothers eye and not the plank in your own?

        Everything about the ‘practice’ of thermography including its advertising and marketing should be subject to tough criticism. I am not disrespectful of Scott’s analysis. What I addressed was what is good public policy. This subject does not occur in a vacuum. When both thermography and mammography emerge into the public arena at the same time it compels comparative consideration. And this consideration needs to be referenced to the ongoing and wider debate about medical testing generally.

        Apply the analytic standards Scott has applied regarding thermography to mammography and let the regulatory enforcement chips fall where they lie. I can live with that. As this is not being done, quite transparently, don’t be surprised if observers take this amiss. My point is, it’s very bad optics and leads to bad regulation. Scott’s good points will be dismissed as just more one-sided propaganda.

        Regarding public opinion et al. Evidence, in this regard, is overwhelming. Another time, if you wish.

        I wasn’t trying to pick a fight. My use of ‘vitriol’ was not aimed at Scott but at the general level of discourse that is typical regarding natural health vs. conventional medicine. It is very hard to generate any productive discussion between partisans on this subject.

Comments are closed.