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Breast Thermography Update: Seven Years of Thermal Imaging in New Zealand (Dec. 2009)

Infra-red thermal imaging (IRT) started in 2002 with a clinic in Tauranga, a branch clinic in Auckland followed by other clinics in both the North and South Island with week-long sessions at regular intervals. A year later, the New Zealand Health Technology Assessment (NZHTA) Unit in Christchurch was instructed by a radiologist and head of the National Screening Unit to report on thermal imaging [1]. Their report concluded that thermal imaging could not be supported because:

  1. There were no NZ studies on effectiveness.
  2. There had been no randomised controlled trials (RCTs).
  3. Different thermal imaging devices had not been adequately compared.
  4. As the histology part of the otherwise blinded U.S. Parisky (2003) trial was not blinded, the study was down-graded from level 3 to 4.
  5. As the index test and the comparators were not blinded, the Canadian Keyserlingk (1998) trial was also graded level 4.
  6. Concerns were raised that in the Parisky trial thermography missed 2.6% of breast cancers as benign.

However, the Parisky multi-centre U.S. study found that thermography correctly identified 97.5% of the 187 breast cancers in 875 subsequently biopsied breast tumours [2]. In addition, the study revealed that in very dense breasts, which are quite difficult to analyse with mammography, thermography had a 98% negative predictive value. In contrast, BreastScreen Aotearoa (2006) acknowledged that mammography could miss 25% of breast cancer in women under 50 and 15% in those over 50 years of age [3]. This was consistent with Miglioretti and associates' subsequent findings in an investigation of 36,000 diagnostic mammograms involving 123 radiologists where an average of 21% of breast cancers were not identified [4]. In February 2007, Boyd and others discussing the management of women with dense fibrocystic breasts whilst not specifically mentioning thermal imaging, concluded "Annual screening in women with extensive mammographic density is not likely to increase cancer detection rate (due to masking)... Attention should therefore be directed to the development and evaluation of alternative imaging techniques for such women" [5].

So, were the NZHTA conclusions and the subsequent fax followed by a 2 page "bad press" glossy sent to every GP by the National Screening Unit justified? The NZHTA’s concerns at Parisky et al. missing 2.6% of the cancers were somewhat bizarre in view of mammography's acknowledged track record. However, it is still true that different cameras have not been adequately compared and standards are still being debated. Fortunately, new German automated software from InfraMedic linked to the latest IR cameras is setting a high standard and notably, their camera is fully registered with the EU as a medical device. Discussions are currently underway to have this as a standard for the whole of New Zealand now that other clinics have either opened (in Auckland) or are soon to open (in Nelson).

So far, over 2500 women (aged between 17- 91 years) have chosen to include thermography in their breast health management. Out of these, 1600 were completely normal. The remainder had varying degrees of thermal or vascular abnormality with 40 having already undergone a mastectomy and 120 later being confirmed as having cancer. Several patients have been identified with subsequently proven breast cancer where difficulties arose due to standard investigations remaining normal despite deteriorating thermograms and in one case where an additional biopsy had also been reported as normal. Some of these obviously abnormal IRT images that were undetectable by x-ray and U/S are shown below. Other women with abnormal thermograms consistent with DCIS, have seen their breast images return to normal following naturopathic and other lifestyle interventions.

IRT identifies a heat signal from the upper 5mm of the skin and is thus suitable for not only identifying the heat from trauma but in theory, also the heat generated by neo-angiogenesis in the breasts. Notably, this well-recognised process where new blood vessels are generated by cancer cells in order to supply them with nutrients is undetectable by any other screening modality. In this regard, Guido and Schnitt observed that angiogenesis is an early event in the development of breast cancer and may occur before there is structural evidence of an in-situ cancer [6]. Spitalier and associates followed 1,416 patients with isolated abnormal breast thermograms for 8 years and found that a persistently abnormal thermogram was associated with an actuarial breast cancer risk of 26% at 5 years [7]. In the 165 patients with non-palpable cancers, thermography was the only test that was positive when compared to mammography and ultrasound in 53% of these patients at the time of initial evaluation. They concluded that a persistently abnormal thermogram, even in the absence of any other sign of malignancy, was associated with a high risk of developing interval cancer. Gautherie also revealed that when breast cancer was detected in 106 patients using thermal imaging when other screening methods were negative there was a 61% improvement in the 5 year survival when compared to 375 controls with both groups having identical treatment [8]. This was effectively a controlled outcome study albeit not randomised. Gautherie and Gros followed 1,527 patients with initially healthy breasts but abnormal thermograms for 12 years and 40% developed malignancies within 5 years and also concluded that "an abnormal thermogram is the single most important marker of high risk for the future development of breast cancer with a 94% predictive value" [9].

More recently, Arora et al. at Cornell after thermography had correctly identified 58/60 carcinomas in their 92 patients referred for biopsy [10] came to much the same conclusion as Parisky [2], namely that IRT was a valuable adjunctive investigation that could differentiate malignancy, especially in those with dense breasts. Furthermore, apparent "false" positives with IRT that were also noted in the Parisky study, should not be dismissed as such but require not only close monitoring but also interventions to potentially improve breast health. Notably, the presence of significantly elevated levels of nickel, iron, chromium and mercury were found in breast cancers when compared with benign breast tumours [11] with all these transitional and potentially carcinogenic metals being widely used in dentistry. Replacement with non-toxic restorations is now recommended by both the Austrian and German Societies of Oncology.

Major concerns have now surfaced regarding both the reliability and the safety of mammograms. Dr. Esserman, a breast surgeon writes in JAMA: "... screening may be increasing the burden of low-risk cancers without significantly reducing the burden of more aggressively growing cancers and therefore not resulting in the anticipated reduction in cancer mortality. To reduce morbidity and mortality from breast cancer, new approaches for screening, early detection, and prevention for both diseases should be considered" [12] (or precisely what IRT does). The American Cancer Society (ACS) chief medical officer, Otis Brawley has also revealed in the NY Times that "...there has been a 40 percent increase in breast cancer diagnoses and a near doubling of early stage cancers with mammography, but just a 10 percent decline in cancers that have spread beyond the breast to the lymph nodes or elsewhere in the body" [13]. All this has revealed that mammography whilst identifying many small indolent tumours can miss the more active and thus more dangerous ones. Furthermore, once a woman has had 5 or more mammograms, the risks of developing cancer significantly increases (1.5 to 2.5 fold increase) from the accumulative radiation [14]. This recent flurry of adverse reports in leading medical journals resulted in the ACS presumably mindful of possible litigation, hastily changing their mammography recommendations. The previous directive of annual mammograms from age 40 changed to a recommendation to start 10 years later and only have a mammogram every other year.

Many physicians and women are also becoming increasingly concerned with the repetitive benign outcomes of breast biopsy following mammography with at least 70% of needle biopsies proven to be benign in two New Zealand investigations during the past 2 decades [15-16]. IRT, with such high negative predicative value (sensitivity) should therefore be considered as an additional tool with which to determine the best and safest management. IRT is uniquely suitable for ongoing monitoring of breast health especially in those with dense breast tissue where masking can obscure detection by x-ray and in monitoring younger women where breast cancer frequently develops more rapidly. Some ethnic groups including Polynesian women, who appear to have a general reluctance to undergo mammography, could also find this no-touch screening modality more acceptable.

The NZHTA independent (albeit with a radiologist's input) and supposedly thorough review has now been criticised as being too selective and significantly failing to include all the published research [17]. However, it has been widely used to further promote mammography as the only reputable breast screening tool. The truth is that properly performed thermal imaging specifically detects the more aggressive "hot" cancers especially in younger woman and in those with dense breasts where mammography admittedly fails (over 500 breast cancers occur every year in NZ in women under age 50 years). Whilst ultrasound, mammography or MRI may still subsequently be needed to accurately locate the tumour, thermography has been proven to be the most sensitive and the earliest marker. Notably, a negative thermogram virtually excludes any developing cancer apart from the rare (1%) "cold" cancer that in any case, has a much lower risk of spreading beyond the breast [18].

Whilst IRT is not yet an approved State subsidised part of breast screening in New Zealand it is a perfectly valid clinical investigation. IRT appears uniquely placed as a stand alone screening procedure for women before the age of 45 and as an adjunctive optional investigation to the subsidised mammography in those between 45 and 69. The two screening methods are complementary and not competitive. Structural screening in some form will always be necessary although published research indicates that IRT is a more sensitive and earlier marker and when both IRT and structural investigations including mammography and U/S are combined, the detection rate increases to 98% [10].

References

  1. Kerr J. Review of the effectiveness of infrared thermal imaging (thermography) for population screening and diagnostic testing of breast cancer. New Zealand Health Technology Assessment (NZHTA) Tech Brief Series July 2004;vol.3; no.3.
  2. Parisky, YR. Sardi A, Hamm R et al. Efficacy of computerized infrared imaging analysis to evaluate mammographically suspicious lesions. American Journal of Roentgenology 2003;180:263-269.
  3. BreastScreen Aotearoa handout to GPs for patient information (2005/2006). CMP Medica(NZ)Ltd. Milford, Auckland.
  4. Miglioretti DL, Smith-Bindman R, Abraham L et al. Radiologist characteristics associated with interpretive performance of diagnostic mammography. Journal of the National Cancer Institute. 2007;99:1854-63.
  5. Boyd NF, Guo H, Martin LJ, Sun L et al. Mammographic density and the risk and detection of breast cancer. N.Eng.J.Med. 2007;356:227-236
  6. Guidi AJ, Schnitt SJ: Angiogenesis in pre-invasive lesions of the breast. The Breast J 1996; (2): 364-369.
  7. Spitalier JM, Ayme Y, Brandone H, Duarte J, El-Ghazawy IMH, et al. : The importance of infrared thermography in the early suspicion and detection of minimal breast cancer. Thermal Assessment of Breast Health (Proceedings of an International Conference), MTP Press Ltd., pp.173-179, 1983
  8. Gautherie M.: Thermobiological Assessment of Benign and Malignant Breast Diseases. Am J Obstet Gynecol 1983 (8)147:861-869
  9. Gautherie M and Gros, C. Breast thermography and cancer risk prediction. Cancer, 1980;45(1): 51-56.
  10. Arora N, Martins D, Ruggerio D et al. Effectiveness of a noninvasive digital infrared thermal imaging system in the detection of breast cancer. Am.J.Surg. 2008; 196(4):523-6.
  11. Ionescu JG, Novotny J, Stejskal V et al. Increased levels of transitional metals in breast cancer tissue. Neuro Endocrinol. Letters 2006; 27(Suppl.1):36-39
  12. Esserman L, Shieh Y, Thompson I. Rethinking Screening for Breast Cancer and Prostate Cancer. JAMA. 2009;302:1685-1692).
  13. Kolata G. Cancer society in shift, has concerns on screening. New York Times, Oct. 20, 2009, page A1
  14. Jansen-van der Weide. M. Radiological Society of North America (RSNA) 95th Scientific Assembly and Annual Meeting: RO22-04. Presented November 30, 2009.
  15. Johnston JA and Clee CZ. Analysis of 308 Localisation Breast Biopsies in a New Zealand Hospital. Australasian Radiology 1991;35(2):148-151\
  16. Greenberg D.et al. Stereotactic breast biopsy: An audit of 18 months at BreastScreen Auckland. Australasian Radiology 2003;47(3):261-267
  17. Ng E.Y-K Int. J. of Thermal Science 2009;48:849-859
  18. Ohsumi S, Takashima S, Aogi K, Usuki H. Prognostic Value of Thermographical Findings in Patients with Primary Breast Cancer. Breast Cancer Res. Treat. 2002;74(3):213-220