Breast cancer screening is in the news once again. Late last year controversy flared around new recommendations in the frequency of screening. (A review of this change can be found Here.) Now it seems that even the type of screening available is generating controversy.
Current breast screening technology in the form of mammograms is a mature approach, the advantages and drawbacks have been extensively studied and are now quite well understood (though more is still being discovered, see the related article at the bottom of this post). As such we can use the mass of accumulated data to create guidelines that attempt to optimise how screening should be done. A balance must be struck between the benefits gained by accurate detection of cancer and the costs, both psychological and financial, of false positives generated by the screening process.
These are the points that must be kept in mind when evaluating new approaches for appropriateness in the consumer screening market. Recently the media has highlighted a minor battle between private medical industry, in the form of breast screening clinic Clinical Thermography, and professional medical organisations and cancer research and advocacy groups. Yesterday the NZ Herald ran a story about the clash, and you can see TV3 coverage Here*.
At issue is the offering of a breast cancer screening service using thermal imaging to detect incipient or established tumours in the breast. The operating principle behind this technique is the requirement of tumours to generate access to their own blood supply early in the process of formation in order to secure the nutrients required for the unrestrained cell growth that is typically associated with cancer.
This process is called angiogenesis and entails the formation of new blood vessels in and around the tumour. This brings a larger amount of blood to the area than would be seen normally and this blood would bring extra body heat with it. Given this information it is not unreasonable to attempt to use this physiological change to attempt to detect cancer. By using high resolution thermal imaging the surface temperature of the breast can be measured and used to infer the presence of “hot spots” that may indicate tumours.
Thermography is not a new technology, developed in the 1960s it was largely abandoned in the early 1980s after an influential trial found the false positive rate and sensitivity unsatisfactory. As such, while the approach is not novel there is a distinct lack of large scale trials from which we can determine the appropriate sensitivity and specificity to apply to the technique and thereby judge it’s efficacy in the screening market, especially using current technology. In particular the technique has been emphasised in the existing literature to have the most impact when used in conjunction with more understood approaches such as mammography.
The current halabaloo seems to centre around concerns by the medical community that the appropriate caveats will not be adequately conveyed to the public and thereby may lead to either unwarranted panic in individuals receiving false positive results or complacency in those that may receive false negative tests. In particular position paper put out by the Cancer Society et al. attempts to raise awareness that the thermography screening process does not have the data to allow the decisions regarding balance between benefit and harm mention above to be made effectively (a position echoed by the UK organisation CancerHelp UK).
In investigating this issue I visited the Clinical thermography website to see what they had to say about the relative effectiveness of Thermography and mommography. I found it revealing that on the FAQ page there were two questions addressing accuracy for Thermography and mammograms. The Thermography entry was essentially an apologetic giving reasons why thermography may give a false negative result, no numbers regarding sensitivity or specificity were included in this.Conversely the mammography entry was a condemnatory piece giving percentages of false negative for the two age groups of particular interest, without any further explanation.
The ommision of hard data in the Thermography portion of the FAQ may reflect the dearth of adequate information as decried by the position statement above or may simply be standard marketing tactics. Either way Clinical Thermography aren’t doing themselves any favours with this evasive approach. Now this is not to say that Clinical Thermography is wholly against mammography, they accurately state earlier in the FAQ that Thermography is not a replacement for mammograms and that the technique should be used in conjunction with other screening methods.
Interestingly an American site for Breast Thermography is careful to include a disclaimer on the front page of the website stating:
“Breast thermography offers women information that no other procedure can provide. However, breast thermography is not a replacement for or alternative to mammography or any other form of breast imaging. Breast thermography is meant to be used in addition to mammography and other tests or procedures. Breast thermography and mammography are complementary procedures, one test does not replace the other….”
This is a straight forward upfront statement that Clinical Thermography would do well to emulate on the front page of it’s own site.
Finally, I’d like to point out that the position I have taken in this post is not contested even by those who would be proponents of this screening method. A commentary piece, published in Minnesota Medicine last December, entitled “Emerging Controversies in Breast Imaging: Is There a Place for Thermography?” was essentially pro-thermography at least in terms of investigating the technique further in order to address the questions raised regarding it’s efficacy.
Quoting from the text of this article:
“The biggest question concerns the efficacy of thermography to detect breast cancer. Despite various studies that suggest positive results for thermography, there has never been a major randomized controlled trial to determine baseline measurements of sensitivity and specificity. It is hard to imagine thermography being accepted by the conventional medical establishment without such data or evidence of cost-effectiveness.”
and:
“In lieu of any industry or professional standards for thermography, a variety of practices and protocols have emerged among practitioners and equipment manufacturers. As one practitioner described it, the industry is in its “Wild West” days.”
In addition, a study linked to on a pro-thermography website concluded:
“we currently limit the role of infrared imaging to that of a closely
controlled compliment to clinical exam and high quailty mammography. Our initial data should not be extrapolated to either formal screening or noncontrolled diagnostic environments without appropriate evaluation, preferably in prospective controlled multicenter trials.”
In summary, Thermography is at this stage a screening method of unproven efficacy. This is not to say that it could not become a valuable adjunctive tool in screening for breast cancer but that caution should be exercised by both promoters and customers of the technology not to oversell or over rely on the results obtained using this technique. Further research should be undertaken to determine the answers the the questions raised about the technique, namely accurate estimates of the sensitivity and specificity of the technique and what role in the screening process it is best suited for.
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*This link seems to be down currently, but a note with regard to Breast Self-Examination (BSE) as mentioned in the TV3 story. This has also come under scrutiny as a practice that does not lead to improved outcomes. See the review of the new breast cancer screening guidelines linked to above.
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- The mammography wars heat up again (sciencebasedmedicine.org)
Scepticon 
While I can appreciate the sensitivity in this article, there are several documents supporting the use of thermography using hundreds of women that were not thoroughly cited in this piece. There is much financial gain to many parties for the continuation of the current regeine of radiating women’s breasts. We are not winning the war on breast cancer, heck, we aren’t even close. Mammography is NOT finding tumors earlier, and may cause cancer. First do no harm….the choice is simple for this girl! Should be a choice for all..Thermography saves lives.
Care to back up the “may cause cancer” part?
I work at a healthcare facility in the mammography department. Annual mammograms and self breast exams are crucial in identifying cancers and increasing survival rates. Recently a patient of ours was called back to have a diagnostic mammo and breast ultrasound (we spot compress masses to see if they will efface.) Cancers have certain characteristics. This mass was large and spiculated and was given a Bi-Rads: 5 – meaning highly suspicious for malignancy. Thanks to thermography, the pt. declined biopsy because there was NOTHING on the thermogram. That woman most likely has cancer. Please, PLEASE trust the effectiveness of mammograms and the highly trained radiologists reading them… It could save your life.
Thanks for that Heather, when someone asks “What’s the harm?” regarding these alternative approaches (be it alternative treatments like homeopathy, or tests like live blood analysis or Thermography) this is the harm.
If people what to be “holistic” and include a range of tests and treatments that’s fine but they should take the best of those and act on all of the information – in this case believing the mammography and following up with a biopsy. Maybe it was fear and denial motivating this action – I can understand that – but perhaps it was ignorance.
Promoting Thermography as if it is equivalent or even superior to mammography does have consequences and this woman may be the one paying them.
From the American Cancer Society: “A mammogram will miss some cancers, and it sometimes leads to follow up of findings that are not cancer, including biopsies…A mammogram cannot prove that an abnormal area is cancer…Although the majority of women with an abnormal mammogram do not have cancer, all suspicious lesions that cannot be resolved with additional imaging should be biopsied for a definitive diagnosis.”
@Heather: If you say claim the woman most likely has cancer due to your opinion of the mammogram results, you are contradicting the ACS. Only a biopsy can determine whether or not a woman has breast cancer.
Neither Mammograms nor Thermal Imaging can prove that a woman has breast cancer. They simply attempts to indicate that something abnormal is occurring. The difference is the accuracy with which they do this. To see how thermography “sees” breast cancer, in confirmed cases of breast cancer, see http://www.tiofsw.com/thermal-imaging/thermography-gallery/.
From research published by the National Cancer Institute: “The false negative rate [mammogram shows no apparent mass, but cancer is present] is 40% among women ages 40 to 49.”
From the National Institute of Health: “Mammograms miss 10% of malignant tumors in women over 50.”
From a study published by The Lancet: (Gøtzsche & Olsen, 2000) based on analysis of Sweden Breast Cancer study and meta-analysis of research into reductions of mortality through mammograms), “Screening for breast cancer with mammography is unjustified. Either…
1.For every 1,000 women screened biennially throughout 12 years, one breast cancer death is avoided whereas the total number of deaths increased by six, or
2.There is no reliable evidence that screening decreases breast-cancer mortality.”
So…to claim that mammograms are accurate is misleading at best. Women trust their mammogram findings, yet abnormalities are usually not cancer, and lack of suspicious findings does not indicate the absence of cancer.
When presented with suspicious findings on thermograms, doctors often recommend ultrasounds, which doctors use to “see” inside the breast during biopsies.
The ACS predicts over 40,000 deaths from breast cancer in 2013. If we are truly interested in saving women’s lives, shouldn’t we give women access to the full range of screening and diagnostic tools, particularly when the “recommended” tools are so often wrong?
David, you seem to have entirely missed the main point. This is not that mammography is perfect, but that thermography is inferior. If you can provide evidence that thermography is not inferior – or that combined mammography and thermography are significantly superior to mammography alone with regard to health outcomes then you may more forcefully make your case.
As it stands your argument could have substituted any unproven screening technique. You state that the difference between mammography and thermography is the accuracy – but spend all your time denigrating mammographyy rather than supporting thermography. Where is your evidence of superior accuracy for Thermography?
I’m glad to contribute to the discussion.
Although my comments were directed at Heather, as a warning against assuming mammogram results definitively indicate cancer, or the lack of cancer, actual research (as opposed to metastudies) is being conducted on thermography, and the research base supporting thermography is expanding. For example:
A. Effectiveness of Noninvasive Digital Infrared Thermal Imaging System in the Detection of Breast Cancer (http://www.ncbi.nlm.nih.gov/pubmed/18809055)
BACKGROUND: Digital infrared thermal imaging (DITI) has resurfaced in this era of modernized computer technology. Its role in the detection of breast cancer is evaluated.
METHODS: In this prospective clinical trial, 92 patients for whom a breast biopsy was recommended based on prior mammogram or ultrasound underwent DITI. Three scores were generated: an overall risk score in the screening mode, a clinical score based on patient information, and a third assessment by artificial neural network.
RESULTS: Sixty of 94 biopsies were malignant and 34 were benign. DITI identified 58 of 60 malignancies, with 97% sensitivity, 44% specificity, and 82% negative predictive value depending on the mode used. Compared to an overall risk score of 0, a score of 3 or greater was significantly more likely to be associated with malignancy (30% vs 90%, P < .03).
CONCLUSION: DITI is a valuable adjunct to mammography and ultrasound, especially in women with dense breast parenchyma.
B. Automatic Detection of Abnormal Breast Thermograms Using Asymmetry Analysis of Texture Features.
http://www.ncbi.nlm.nih.gov/pubmed/23194447
Thermography is a non-invasive imaging modality that represents surface temperature variations of the skin in the form of images called thermograms. The surface temperature around the area of cancerous cells is slightly higher than normal tissues and this area is seen as hot spots on thermograms. In normal breast thermograms, symmetric heat patterns are observed in both breasts, but in the case of unilateral abnormality, asymmetry is observed. As the intensity variations in thermograms represent surface temperature changes, texture features that would enhance thermal asymmetry, between right and left breasts, have been studied. The texture features are extracted from the breast region and fed to a back propagation neural network for automatic detection of abnormal breast thermograms. The classifier is able to classify abnormal and normal thermograms with an accuracy of 85.19%. From the results of the study, it is inferred that thermography has the potential to detect breast cancer and can be used as an adjunct tool to mammography.
I’ll add one more point to address the combination of mammography and thermography.
A 1974 study, conducted prior to significant advances in thermographic imaging technologies and analysis, found that “In preclinical cancer, the accuracy is greater when thermography and mammography are used together than with mammography alone.” The authors also noted that “Thermography with clinical examination appears to be adequate for the initial screening of women, reserving mammography for those with abnormal thermograms or clinical findings.
http://onlinelibrary.wiley.com/doi/10.1002/1097-0142(197406)33:6%3C1671::AID-CNCR2820330630%3E3.0.CO;2-4/pdf
Other studies have since suggested that thermography and mammography combined produce more accurate results than mammography alone.
Thanks for that, it seems to me that both of your comments actually support Heather.
Both comments suggest to me that Thermography AND mammography should be used in conjunction to get the best out of the techniques. Whereas in Heather’s anecdote the patient was completely ignoring one method in favour of another. Were the story reversed and the patient ignored a positive thermogram in favour of a negative mammogram would you be so forthright in your condemnation?
At the very least the paient, having consented to both procedures, should have taken both seriously. To say otherwise would be to imply 100% infallibility to thermography. A position that I think no-one would support?
Just recently my wife had a breast thermography done because she had a palpable lump on her right breast outer quadrant. The results were negative no signs of inflammation or lumps. She had an ultrasound on her right breast 6 days later results at this time are bi rads 5 with a 1.8 cm highly probable malignancy and possible multiple lymph node metastasis. The thermography technician did not want to send us the photos only the results, but she eventually did, and a naturopath said he wouldn’t do anything about the lump because the thermo was negative – that was before the ultrasound. My wife eats healthy and is in to natural approaches but this has left her very upset. Thermography is not good for breast cancer. Have a breast ultrasound done.
Thank-you for sharing this. I sense a theme developing where those in favour of thermography want mammography (or ultrasound) supplemented with thermography but when the situation is reversed feel that thermography need not be backed up with any other technique.
Complementary indeed.