Scientists and physicians do not know why most women get breast cancer, yet breast cancer is the most frequent malignancy in women worldwide, and the annual incidence of breast cancer increased 55% between 1950 and 1991 [1]. IARC (the International Agency for Research on Cancer) reports breast cancer is the most common female cancer in industrialized countries, and second to cervical cancer in developing countries. Only about 5% of breast cancer is inherited, and about 80% of women diagnosed with the disease will be the first in their families to get breast cancer. Cumulative exposure to synthetic estrogen and xenoestrogens, and ionizing radiation underlie most of the known risk factors.
Current Recommendations
Current recommendations for routine screening for breast cancer vary according to the source. The American Cancer Society, American College of Radiology, American Medical Association, American College of Obstetricians and Gynecologists recommend:
• Clinical breast exams by a physician and mammography every 1-2 years, beginning at age 40.
• Annual clinical breast exams and mammography, beginning at age 50.
The American College of Physicians recommends:
• Screening mammography every 2 years for women aged 50 -74 and recommends against mammograms for women under 50 or over 75 years of age.
• There is no difference in high-risk women, unless the women expresses great anxiety about breast cancer.
Is Screening Effective?
Multiple clinical studies have been undertaken to determine the relative effectiveness of screening, but there is variation in length of the studies as well as other parameters that accounts for some variation in results. Clinical examination (physician manual examination of the breasts) has limitations with a sensitivity rate often below 65%. In a large Canadian study, sensitivity of clinical breast examination for women age 40-49 was about 10% lower at initial screen than for women aged 50 - 59. Mammography sensitivity varied as well, from 75% up to 88%, depending upon the study and also the radiologist interpreting the study. [2,3-6] Monthly self-breast examinations have also been suggested but the efficacy of these varies tremendously as well.
Danish researchers published a study in 2002 suggesting that mammograms do not lead to a reduction in the breast cancer death rate or the number of major surgeries for the disease. This created an uproar in the United States where The National Cancer Institute and others disagreed with the Danish findings. This is an emotionally charged topic. Proponents of annual mammograms point out that early detection reduces breast cancer mortality by 20-30%. [11] Other studies, however, show the annual age-adjusted mortality rate from breast cancer since 1930 is relatively unchanged to present. [12]
Is There a Downside to Screening?
Adverse effects of screening tests are also an important consideration. False-positive tests, resulting from the effort to maximize disease detection, may have negative consequences including unnecessary diagnostic tests. In the Canadian trials there were 7-10% false positives combined with clinical breast exams in women aged 40-49 and 4.5% - 8% among those aged 50 -59. In a study of the yield of a first mammogram, 3 cancers per 1000 were found in women age 40 - 49 compared to 6 cancers per 1000 in women aged 50 - 59. Yet the younger women underwent twice as many diagnostic tests per cancer. Some studies have reported an increased anxiety about breast cancer after a false-positive mammogram. Women who underwent biopsy as a result of a false-positive screening mammogram were more likely to report their evaluation as stressful than those who did not have a biopsy. There are also concerns about the radiation exposure risk to breast tissue from screening mammograms. Although a mean breast dose of 0.1 rad from a mammogram is considered a low dose of radiation by traditional medicine, there are no clinical studies showing what the consequences of cumulative annual low dose radiation would be after 10 or 20 years. We do know ionizing radiation causes free radical formation, tissue and DNA damage, which are cancer risks. As with any procedure, we encourage our patients to always weigh the risks of the procedure with the benefits derived. [7 - 10]
Digital Infrared Thermal Imaging (Breast Thermography)
Digital Infrared Thermal Imaging is a 15 - 30 minute non invasive test of physiology. It is a valuable procedure for alerting your doctor to changes that can indicate early stage breast disease and in the evaluation of unexplained pain. Benefits include:
• Non invasive
• No radiation
• Painless
• No contact with the body
• F.D.A. approved
A very sensitive digital camera takes thermal images of the body and sends this data to a computer. The images are then interpreted by a qualified physician. In this way, skin temperatures, thermal and vascular patterns, and sympathetic responses can distinguish between normal and abnormal physiological function of the body. This is different than an X-ray, where radiation is passed through the body and an image is developed on an X-ray plate film to produce an anatomical image.
The underlying principle by which infrared imaging detects pre-cancerous and cancerous growths is because tumors have an increased vascularity in order to maintain the increased metabolism of cellular growth and multiplication. With this increased blood-flow comes an increased temperature, even in very small tumors. Like mammography and other breast imaging techniques, infrared imaging does not diagnose cancer (only biopsy can) – but merely indicates the presence of an abnormality. However, a woman’s thermal image is like a thumbprint and should not change over time. Serial studies are compared with previous studies for changes. If a women has never had a breast thermogram before, an initial thermogram is performed and then a repeat study is done three months later to establish an accurate baseline. After this, annual thermography can be performed and compared with previous studies.
Thermography is very accurate compared to other methods of detection and screening. Spitalier and associates followed 61,000 women using thermography over a 10 year period of time. They found the false negative and false positive rate was in the 11% range (89% sensitivity and specificity). Of the breast cancers that could not be felt on breast exam (nonpalpable), 9 in 10 were detected by thermography. Of all the patients with cancer, thermography alone was the first alarm in 60% of the cases. The physicians involved noted “in patients having no clinical or radiographic suspicion of malignancy, a persistently abnormal breast thermogram represents the highest known risk factor for the future development of breast cancer.” [13] Thermography is especially useful where mammography has a more difficult time – in younger women with dense breast tissue, women on hormonal replacement, and women with fibrocystic breasts. When thermography, mammography, and clinical breast exam are combined, 95% of all early breast cancers will be detected.
Because of thermography’s unique ability to image the thermovascular aspects of the breast, extremely early warning signals (from 8-10 years before any other detection method) have been observed in long-term studies. Consequently, thermography is the earliest known indicator of the future development of breast cancer and has a significant place as one of the front-line methods of breast health screening.
REFERENCES
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[2] Robertson CL. A private breast imaging practice: medical audit of 25,788 screening and 1,077 diagnostic examinations. Radiology 1993; 187:75-79.
[3] Fletcher SW, Black W, Harris R, et al. Report of the International Workshop on Screening for Breast Cancer. J Natl Cancer Inst 1993;85:1644-1656
[4] Peeters PH, Verbeek AL, Hendriks JH, et al. Screening for breast cancer in Nijmegen. Report of 6 screening rounds, 1975-1986. Int J Cancer 1989; 43:226-230
[5] Tabar L, et al. What is the optimum interval between mammographic screening examinations? An analysis based on the latest results of the Swedish two-county breast cancer screening trial. Int J Cancer 1987; 55:547-551.
[6] Baines CJ, McFarlane DV, Wall C. Audit procedures in the National Breast Screening Study: mammography interpretation. J Can Assoc Radiol 1986;37:256-260.
[7] Miller AB, Baines CJ, et al. Canadian National Breast Screening Study: 2. Breast cancer detection and death rates among women aged 50 to 59 years. Can Med Assoc J 1992;147:1477-1488
[8] Miller AB, Baines CJ, et al. Canadian National Breast Screening Study: Breast cancer detection and death rates among women aged 40 to 49 years. Can Med Assoc J 1992;147:1459-1476
[9] Kerlikowske K, Grady D, Barclay J, et al. Positive predictive value of screening mammography by age and family history of breast cancer. JAMA 1993;270:2444-2450.
[10] Gram IT, Lund E, Slenker SE. Quality of life following a false positive mammogram. Br J Cancer 1990; 2:1018-1022.
[11] Tabar L, Fagerberg G, Duffy SW et al. Update of the Swedish two-country program of mammographic screening for breast cancer. Radiol Clin North Am 1992;30:187-210.
[12] Wingo PA, Tong T, Bolden S. Cancer statistics, 1995. CA Cancer J Clin 1995;45:8-30.
[13] Spitalier, H., Giraud, D., et al: Does Infrared Thermography Truly Have a Role in Present-Day Breast Cancer Management? Biomedical Thermography, Alan R. Liss New York, NY pp. 269-278,
