By Katherine Smith.
Thermography offers women a breast screening technique that does not expose breast tissue to carcinogenic radiation, or uncomfortable (or downright painful) breast compression.
For just these two reasons alone it is an attractive option for women who want to avail themselves of technology that could potentially help to detect breast cancer at an early stage. In the case of thermography, the technology even has the potential to give early warning of pre-cancerous changes in the breasts – allowing timely interventions to improve their health and prevent breast cancer from developing.
Thermography is not marketed in NZ as a cancer detection tool but as an adjunct to mammography. Like any technological tool, thermography has strengths and weaknesses. (Unlike mammography, for example which can identify where in a breast a tumour is located, thermography cannot give more than an area of suspicion in which a tumour may be located.)
However, given that many women who have been persuaded to have a first mammogram do not ever want to have a second one on account of the pain, it is likely that a growing number of women will seek out thermography as a sole breast screening tool, rather than return for mammograms.
Having a breast thermogram simply involves sitting topless in front of an infrared camera (operated by a female nurse) and changing position every so often so that different areas of the breasts can be imaged. Some thermography providers ask their clients to place their hands in a bowl of icy cold water for a few minutes so that differences in blood flow within breast tissue can be observed before and after this “cold challenge” test; however on the whole the test is dignified and completely painless.
Unfortunately, mainstream radiology which is in the business of squashing women’s breasts (one of the most radiation sensitive tissues in the human body) between two glass screens and x-raying them is not happy that there is a new, radiation-free competitor on the block, and that women are in many cases voting with their feet and paying for thermograms (which cost approximately $200) compared to approximately $160 mammogram for women who are not eligible for free mammograms as part of NZ’s national, taxpayer funded mammography service Breast Screen Aotearoa.
According to the NZ Herald “College representative Dr Mike Baker, an Auckland radiologist, said last night that the industry should be closed down – ‘because there’s no scientific evidence to support thermography’.”
This is rubbish, of course, but unfortunately the NZ Herald reporter let the statement go unchallenged.
A follow up story (September 27) by Martin Johnson quoted health advocate Allison Roe (who has featured on advertisements for Clinical Thermography) as stating that Dr Mike Baker’s comments calling for thermography businesses to be shut down were “defamatory and malicious”.
The article also included quotes from Josie Taylor (age 40) from the Auckland suburb of Glenfield. Ms Taylor’s thermogram showed a “positive result on the Friday before Queen’s Birthday in June…She had been told of this possibility but it did not lessen the agony of being unable to get medical advice during the long weekend.”
After she “‘broke down’” at reception at a medical breast screening clinic, upon learning that there was a 2-3 week waiting list, she was taken through for a mammogram and ultrasound which were negative for breast cancer.
Her advice to women: “‘Stick with what is tried and tested’”
The final lines of the article read:
“Breast surgeon Belinda Scott said thermography picked up about 18 pecent of cancers, in contrast to about 85% for mammography in women aged 45 to 70.”
The reporter offers no substantiation for either of these assertions. In the case of mammography, the claim of 85% detection does not appear to be accurate for younger women, as information on the website of Women’s Health Action states:
“False negative results
This means actual cancers are missed. About 10% of invasive breast cancers are not detected by mammography in women 50-59 years. In women 40-49 up to 25% are missed. False negatives can give women false reassurance that cancer is not present and may delay them reporting symptoms to their doctor.”
The American Journal of Surgery (Vol 196, No. 4, October 2008) discusses a study in 1980 in which the researchers found that patients with a thermogram rate stage Th IV or V “had a 90% chance of having cancer at the time of the study and more interestingly 38% of the patients of the 1,245 patients with Thermogram Th III (suspicious but not conclusive) developed cancer within 1-4 years of follow up.” The conclusion to their own study stated that “a modernized DITI system can be a useful adjunct test in detecting breast cancer with 97% sensitivity in this prospective trial of 92 patients.” (Sensitivity refers to the ability of a test to correctly identify that a patient is suffering from a certain condition.)
According to the International Journal of Thermal Sciences 48 (2009) 849-859:
“International research about thermography shows that the new thermography cameras, combined with analytical software and personnel can offer useful information about breast health. For the last 1.5 decades of complying with the strict standardized thermogram interpretation protocols by proper infrared trained personnel as documented in the literature, breast thermography has achieved an average sensitivity and specificity of 90%. An abnormal thermogram is reported as the significant biological risk marker for the existence of or continued development of breast tumor.”
This means that the false positive rate and false negative rates for thermography are similar to that of mammography. Clearly thermography is a real competitor with mammography; if it were really the sort of “lame duck” technology as alleged by its detractors, they would not be wasting their time dissing it in mainstream media.
The turf battle between radiographers who want to continue business as usual with mammograms and the new businesses offering thermography raises other important questions.
Screening for health problems is an area which may appear to be give personal and social benefits, but also involves substantial risks.
In the case of mammography, the ionising radiation used increases the risk of developing breast cancer. Statistics about the risk vary according to different studies. According to information on the Women’s Health Action website:
“The radiation risk from modern mammography is extremely low. For a woman attending breast screening every two years from the age of 50 to 64, the possible risk of dying from a breast cancer caused by radiation is estimated to be one in 20,000. For a woman who starts annual mammography at the age of 40, then has it every two years from 50 to 64, there would be one radiation induced breast cancer death per 10,000 women.”
According to Dr Samuel Epstein, (author of The Politics of Cancer) who has spent the last few decades fighting to reduce the exposure of the American public to carcinogens that are fueling that country’s cancer epidemic) mammography (as practised in the USA) entails substantial cancer risks:
“Radiation from routine mammography poses significant cumulative risks of initiating and promoting breast cancer (1- 3). Contrary to conventional assurances that radiation exposure from mammography is trivial- and similar to that from a chest X-ray or spending one week in Denver, about 1/ 1,000 of a rad (radiation-absorbed dose)- the routine practice of taking four films for each breast results in some 1,000-fold greater exposure, 1 rad, focused on each breast rather than the entire chest (2). Thus, premenopausal women undergoing annual screening over a ten-year period are exposed to a total of about 10 rads for each breast. As emphasized some three decades ago, the premenopausal breast is highly sensitive to radiation, each rad of exposure increasing breast cancer risk by 1 percent, resulting in a cumulative 10 percent increased risk over ten years of premenopausal screening, usually from ages 40 to 50 (4); risks are even greater for “baseline” screening at younger ages, for which there is no evidence of any future relevance. Furthermore, breast cancer risks from mammography are up to fourfold higher for the 1 to 2 percent of women who are silent carriers of the A-T (ataxia-telangiectasia) gene and thus highly sensitive to the carcinogenic effects of radiation (5); by some estimates this accounts for up to 20 percent of all breast cancers annually in the United States (6).”
According to information that I have obtained by making a request under the Official Information Act, for New Zealand women who have mammograms as part of BreastScreen Aotearoa “The average glandular dose [of radiation] must be less that 3mGy (0.3 rad) for a single view of a breast.” (In the BreastScreen Aotearoa, two views are usually taken of each breast, compared to four views of each breast in the example of the American women cited by Dr Epstein. ) This means that the “average” New Zealand’s woman’s radiation exposure from mammography appears to be lower than that of American women – because BreastScreen Aotearoa offers mammograms on a two yearly (rather than an annual) basis and only two images of each breast are taken at most screening sessions.
To add insult to injury as it were, there is also some evidence to suggest that mammography may not reduce breast cancer mortality.
An article in the Journal of the National Cancer Institute in 2000 concluded:
“In women aged 50–59 years, the addition of annual mammography screening to physical examination has no impact on breast cancer mortality.”
Nor does there seem to be a benefit for younger women. 50,430 Canadian women participated in a study with the following objectives:
“To compare breast cancer mortality in 40- to 49-year-old women who received either 1) screening with annual mammography, breast physical examination, and instruction on breast self-examination on 4 or 5 occasions or 2) community care after a single breast physical examination and instruction on breast self-examination.”
The authors concluded:
“After 11 to 16 years of follow-up, four or five annual screenings with mammography, breast physical examination, and breast self-examination had not reduced breast cancer mortality compared with usual community care after a single breast physical examination and instruction on breast self-examination.”
At this point I would like to state for the record that I have not reviewed all the literature I could find on mammography; these two studies happened to be free full text articles that I could access easily online. There could be other studies that show a benefit to mammography of which I am unaware.
Good news on the horizon is that an article in Archives of Internal Medicine (2008) that provided evidence that some breast cancers may spontaneously regress.
The original article may be read in full at the following link:
The authors of the article conclude:
“Finally it is also important to emphasize that our findings have no bearing on the debate on whether screening mammography reduces breast cancer mortality. Our findings are equally consistent with the possibility that mammography either leads to a reduction in breast cancer mortality or has no effect at all. Instead, our findings simply provide new insight on what is arguably the major harm associated with mammographic screening, namely, the detection and treatment of cancers that would otherwise regress.”
Which brings me to my next point:
In a paper presented in June 2000 at Healthy Women Workshop Education & Training for Health Promotion National Cervical Screening Programme and BreastScreen Aotearoa, Sandra Coney stated:
“Screening programmes can be viewed as a form of social contract in which large numbers of women agree to participate to ultimately benefit a very few. We owe it to these women to ensure that they make a fully informed decision to participate and that the standards reached in programmes is high. We can only know that after thorough ongoing monitoring and evaluation. After a decade, this has not occurred in cervical screening and it is too early to know whether the processes put in place in breast screening will guarantee standards and goals for the programme are met.”
It appears to me that ten years on from this presentation, Breastscreen Aotearoa does not offer women anything like informed consent: as these excerpts from its website demonstrate:
“Are mammograms safe?
Only a very small amount of radiation is used in mammography so the radiation risk is extremely low.”
“Do I need to have mammograms when there is no history of breast cancer in my family?
Yes, you do. Most women who develop breast cancer have no close relatives with the disease.”
Leaving aside the issue of radiation, I take exception to the assertion that breast screening is necessary. Screening of healthy people for any disease is not a “need” but an option which some people will consider desirable but others may not: As Sandra Coney wrote:
“Thousands of women must take part in programmes to prevent a single case of cervical cancer or to prevent a single premature death from breast cancer. Many women will go through the anxiety and trauma of being recalled for further assessment, then be given the all clear. All women who take part in programmes risk a personal cost, even in the best run of programmes.”
(These costs may include the risk of treating cancers that may have never otherwise have been diagnosed because they were asymptomatic at the time of detection and may never have developed to a point at which they posed a threat to health or life, as discussed above.)
Sandra Coney continues:
“It is even difficult [for women who are being recruited into the national cervical smear programme] to find what the benefit of cervical screening is. In fact the benefit is substantial. Women having regular smears reduce their risk of dying from cervical cancer by over 90%. This is a very significant benefit and contrasts with the benefit of regular breast screening which is around 25 to 30%. Of course breast cancer is a more common disease, especially in older women.
“The first step for women making a choice about whether to be screened is to understand their underlying risk, yet this is an area where women have a very poor understanding and screening programmes make very little attempt to enlighten women.
“The average 20-year-old woman has about a 250 in 10,000 chance of developing cervical cancer and about a 118 in 10,000 chance of dying from it. Regular screening at least every three years from 20 to 75 years reduces the risk of developing cancer by about 215 in 10,000 and the risk of dying by 107 in 10,000. The average 50-year-old woman has a one in 42 chance of dying of breast cancer before she turns 75. Regular screening reduces this risk to one in 60. *”
Leaving aside the controversy as to whether or not the reduction in death from breast cancer attributed to mammography is accurate, these figures demonstrate basic fact: that the majority of women will not develop either breast or cervical cancer and therefore will not die from either of these diseases regardless of whether or not they decide to participate in screening programmes.
It is perhaps this silent majority who has the most to lose from health screening programmmes, as the following story illustrates:
“At age 40 my doctor suggested I begin with annual mammograms. The first two years were fine, the results were negative. But at age 42 the result came back with a suspicious area in my right breast. I had additional testing done with ultrasound and such and it was suggested I have a biopsy. Scheduling for the testing and waiting for the results were quite difficult and I started having trouble sleeping. My doctor gave me a prescription for Xanax which helped a lot. Fortunately the biopsy came back negative. However, since I don’t have insurance, I am a computer graphic expert working from home, it cost me several thousand dollars. I continued with mammograms and at age 45 now the left breast showed something suspicious. This time my nerves couldn’t handle it and I resumed on the Xanax. I started getting hooked on the drug. It made me lethargic and made me lose interest in sex. My doctor suggested I have a repeat mammogram in 6 months. During this time my stress and anxiety became quite severe, I started having arguments and fights with my husband and children.
“To make a long story short, my husband left me, I wasn’t sexually intimate with him anymore, the Xanax had taken my sexual urges away. The follow up mammogram was normal and I did not need a biopsy. However, 3 years later I had another suspicious mammogram which again necessitated a biopsy, fortunately it turned out to be normal. At this time I am 51 years old and have not had a cancer diagnosis but this whole testing has been bad for my health. I wish I had never done these tests. They have cost me close to 15,000 dollars over the past decade… I could instead have taken several vacations to Hawaii. It has also effected my marriage and work, and made me think of my breasts as harbingers of potential tumors rather than sensual organs. I hope these new recommendations will make fewer women go through the awful stress and anxiety I endured. I am, unfortunately, still hooked on Xanax, particularly when the time comes to schedule a cancer screening test. At other times passion flower or kava help me relax and avoid the medication.”
This was an American woman: had she been a New Zealander the financial stress may have been less as some of the procedures she underwent may have been available within the public health system. However the anxiety she suffered is real and mirrors the experience of Josie Taylor.
In my opinion, women should think carefully before participating in any cancer screening programme, whether a national programme such as Breastscreen Aotearoa or the National Cervical Screening Programme*, or through a private provider such as a thermography screening business. For those who find the thought of possibly having cancer completely terrifying, screening may not be in the best interests of their mental or physical health, since any abormality detected even if minor, may cause significant anxiety.
On the other hand, for women who want to be proactive about their health, availing themselves of screening services (combined with a healthy lifestyle) can be a positive choice.
*NB: It is possible to have cervical smear tests in NZ without joining the National Cervical Screening Programme, however, it requires obtaining and signing an “opt off” form. Without opting off, all details are collected as part of the programme and medical records of those women who do develop cervical cancer can be passed onto medical researchers without the permission of the individual woman concerned.