About Breast Thermography

Breast Thermography – An Overview

What is Breast Thermography?

Breast thermography is a physiological test that provides information on temperature and infrared heat patterns of the breast1. Because the skin naturally radiates heat, it is well suited to infrared imaging2. Thermography differs from mammography in that it provides information on the biological activity of the breast versus the gross internal anatomy3. Infrared imaging is therefore a functional test whereas mammography is a structural test4.

As a functional test, thermography can detect breast abnormalities that other screening methods cannot identify, namely thermal and vascular changes. The increased metabolic activity seen on a breast thermogram can be an indication of injury, mastitis, fibrocystic breast disease or cancer5. These functional changes are thought to take place before the onset of structural changes that can occur in diseased or cancerous states. A persistent abnormal thermogram can alert the physician to the need for further investigation and identify women who need to be more closely monitored6-8.

Because thermograms in a healthy woman remain remarkably constant, serial thermograms can assess tissue changes over time9. A healthy initial thermogram can therefore serve as a baseline to compare future thermograms against.

Understanding the Strengths of Breast Thermography

Thermography is a non-invasive, contact-free procedure that doesn’t require compression of the breasts9. There is no exposure to radiation, which means repeat tests are safe and without risk16. Thermal imaging has been approved by the Food and Drug Association of America since 1982 as an adjunctive screening tool for breast cancer12.

One of the key benefits of thermography is its effectiveness in women with dense breasts, making it suitable for4:

  • Younger women – approximately 18% of breast cancers are diagnosed in women during their forties. Women who develop breast cancer at a younger age tend to have more rapidly growing cancers that are more likely to metastasize (spread throughout the body)17.

  • Women taking hormone therapy – results from the Women’s Health Initiative trial revealed a significant increase in invasive breast cancer when taking synthetic hormone replacement therapy18. Serial thermograms can also help monitor the effects of hormone treatment for fibrocystic breasts19.

  • Women with fibrocystic changes – fibrous breasts are very dense and can mask early cancers, particularly if no microcalcifications are present. Research has shown that approximately 40% of women with fibrocystic disease and an abnormal thermogram develop breast cancer within 5 years. Conversely, women with fibrocystic disease and a normal thermogram have a less than 3% likelihood of developing breast cancer19.

Thermography can also provide early warnings of breast abnormalities and highlight potentially suspicious cases particularly when mammographic and clinical exams are equivocal or non-specific10.

Thermography as an Independent Risk Marker

An estimated 60-70% of women diagnosed with breast cancer have none of the obvious risk factors. For this reason, breast cancer has been considered an equal opportunity killer20. According to a number of researchers, a persistent abnormal thermogram is thought to be “the single greatest indicator of breast cancer risk” and is considered 10 times more important than a positive family history for the disease19-20. Because physiological changes over time are known to precede morphological changes, an abnormal thermogram can often be the first warning sign of an increased risk for breast cancer13,16,21,22.

A repeated abnormal thermogram in the absence of a palpable cancer or abnormal mammogram is associated with a greater than 30% increased risk of developing breast cancer within 10 years13, 15. This equates to a rate of breast cancer 6 times higher than what would ordinarily be expected from a normal population20. Early detection of breast cancer initiated solely by an abnormal thermogram and followed up with treatment intervention (e.g. radiotherapy or surgery) has been shown to significantly increase 5 and 10 year survival rates (36% vs. 24% in the radiotherapy group and 44% vs. 33% in the surgery group)19.

The Value of Thermography as a Complementary Tool

An increase in the detection rate of breast cancer has been demonstrated in a number of peer-reviewed studies with the combined use of clinical breast examination, mammography and thermography6,10,13,21,23-25. In one study using high resolution thermography, an abnormal thermogram coupled with a positive mammogram and clinical breast exam was associated with a 98% sensitivity rate for breast cancer detection10. Results from a recent 2010 trial showed an 89% sensitivity rate for the detection of breast cancer in women under 50 when thermal imaging and mammography were combined25.

The increase in sensitivity relates to the fact that mammography and thermography do not always identify the same lesion6. For example, Gamagami’s research revealed that thermography is able to detect changes in breast temperature and vascularity in 86% of non-palpable breast cancers. He also found that thermal imaging was able to detect 15% of cancers not visible through mammographic assessment10. Based on the extensive research by Gautherie and Gros, approximately 10% of breast cancers can be detected at an earlier stage with the combined use of thermal imaging13.

Thermography’s Place in the Fight Against Breast Disease

Thermography cannot and does not diagnose breast cancer. This is true also for anatomical tests such as mammograms, ultrasounds and magnetic resonance imaging. Such tests provide information on the different aspects of the disease process and identify the need for further investigations1. A biopsy of the breast and accompanying histological evaluation is the only definitive diagnostic test for breast cancer8.

Historically, infrared cameras lacked the sensitivity to detect subtle temperature changes necessary to identify and monitor disease but since the 1990’s, major advancements in infrared technology coupled with sophisticated computerised software programmes have resulted in a significant increase in the accuracy of thermal images10. For example, a 4-year clinical trial by Parisky and colleagues demonstrated a 97% sensitivity in the detection of breast cancer with the use of dynamic computerised thermal imaging11. In another recent trial, modern digital thermography was also able to detect 97% of biopsy-confirmed breast malignancies12.

False’ positive results are often a reflection of breast abnormalities that are not yet palpable through breast examination or detectable through mammograms. Early research assessing approximately 58,000 women has shown that a significant percentage (>30%) of abnormal thermograms in the absence of any other breast abnormalities eventually manifest at a later stage as cancer13.

Because thermography cannot provide information on the exact anatomic detail of the breast or define a specific area that needs to be biopsied, it needs to be combined with an anatomical test such as mammography9, 14. As a functional test, thermography cannot identify the specific cause of physiological changes to breast tissue. For this reason, it serves as a risk marker and complementary modality, rather than a standalone assessment tool15,16.

Summary

Thermography is not a competitor to, or a replacement for mammography, rather it is an adjunct tool that can identify areas of abnormal thermal symmetry which are often associated with underlying pathology26. When functional abnormalities are detected early, there is an opportunity for early intervention9,10,13,27. Cure rates for breast cancer are thought to be as high as 95% when detected in the earliest stages28.

According to Ng and Kee, when combined with other anatomical procedures, thermography “may contribute to the best possible evaluation of breast health”29.

References

  1. Ng EY, Ung LN, Ng FC, Sim LS. Statistical analysis of healthy and malignant breast thermography. J Med Eng Technol. Nov-Dec 2001;25(6):253-263.
  2. Joro R, Laaperi AL, Dastidar P, et al. Imaging of breast cancer with mid- and long-wave infrared camera. J Med Eng Technol. May-Jun 2008;32(3):189-197.
  3. Isard HJ. Other imaging techniques. Cancer. Feb 1 1984;53(3 Suppl):658-664.
  4. Plotnikoff G, Carolyn T. Emerging controversies in breast imaging: is there a place for thermography? Minn Med. Dec 2009;92(12):37-39, 56.
  5. Mital M, Scott EP. Thermal detection of embedded tumors using infrared imaging. J Biomech Eng. Feb 2007;129(1):33-39.
  6. Isard HJ, Becker W, Shilo R, Ostrum BJ. Breast thermography after four years and 10000 studies. Am J Roentgenol Radium Ther Nucl Med. Aug 1972;115(4):811-821.
  7. Gautherie M. Thermopathology of breast cancer: measurement and analysis of in vivo temperature and blood flow. Ann N Y Acad Sci. 1980;335:383-415.
  8. de Thibault de Boesinghe L. The value of thermography for the diagnosis, prognosis and surveillance of non-palpable breast cancer. J Belge Radiol. Oct 1990;73(5):375-378.
  9. Kennedy DA, Lee T, Seely D. A comparative review of thermography as a breast cancer screening technique. Integr Cancer Ther. Mar 2009;8(1):9-16.
  10. Keyserlingk JR, Ahlgren PD, Yu E, Belliveau N, Yassa M. Functional infrared imaging of the breast. IEEE Eng Med Biol Mag. May-Jun 2000;19(3):30-41.
  11. Parisky YR, Sardi A, Hamm R, et al. Efficacy of computerized infrared imaging analysis to evaluate mammographically suspicious lesions. AJR Am J Roentgenol. Jan 2003;180(1):263-269.
  12. 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. Oct 2008;196(4):523-526.
  13. Gautherie M, Gros CM. Breast thermography and cancer risk prediction. Cancer. Jan 1 1980;45(1):51-56.
  14. Agnese DM. Advances in breast imaging. Surg Technol Int. 2005;14:51-56.
  15. Head JF, Wang F, Lipari CA, Elliott RL. The important role of infrared imaging in breast cancer. IEEE Eng Med Biol Mag. May-Jun 2000;19(3):52-57.
  16. Ng EY, Sudharsan NM. Computer simulation in conjunction with medical thermography as an adjunct tool for early detection of breast cancer. BMC Cancer. Apr 28 2004;4:17.
  17. Berg WA. Benefits of screening mammography. Jama. Jan 13 2010;303(2):168-169.
  18. Rossouw JE, Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial. Jama. Jul 17 2002;288(3):321-333.
  19. Gautherie M. Thermobiological assessment of benign and malignant breast diseases. Am J Obstet Gynecol. Dec 15 1983;147(8):861-869.
  20. Keith LG, Oleszczuk JJ, Laguens M. Are mammography and palpation sufficient for breast cancer screening? A dissenting opinion. J Womens Health Gend Based Med. Jan-Feb 2002;11(1):17-25.
  21. Gautherie M, Haehnel P, Walter JP, Keith LG. Thermovascular changes associated with in situ and minimal breast cancers. Results of an ongoing prospective study after four years. J Reprod Med. Nov 1987;32(11):833-842.
  22. Head JF, Elliott RL. Infrared imaging: making progress in fulfilling its medical promise. IEEE Eng Med Biol Mag. Nov-Dec 2002;21(6):80-85.
  23. Stark AM, Way S. The screening of well women for the early detection of breast cancer using clinical examination with thermography and mammography. Cancer. Jun 1974;33(6):1671-1679.
  24. Nyirjesy I, Billingsley FS. Detection of breast carcinoma in a gynecologic practice. Obstet Gynecol. Dec 1984;64(6):747-751.
  25. Wishart GC, Campisi M, Boswell M, et al. The accuracy of digital infrared imaging for breast cancer detection in women undergoing breast biopsy. Eur J Surg Oncol. Jun 2010;36(6):535-540.
  26. Jones CH, Greening WP, Davey JB, McKinna JA, Greeves VJ. Thermography of the female breast: a five-year study in relation to the detection and prognosis of cancer. Br J Radiol. Jul 1975;48(571):532-538.
  27. Stark AM. The value of risk factors in screening for breast cancer. Eur J Surg Oncol. Jun 1985;11(2):147-150.
  28. Lin QY, Yang HQ, Xie SS, Wang YH, Ye Z, Chen SQ. Detecting early breast tumour by finite element thermal analysis. J Med Eng Technol. 2009;33(4):274-280.
  29. Ng EY, Kee EC. Advanced integrated technique in breast cancer thermography. J Med Eng Technol. Mar-Apr 2008;32(2):103-114.
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