Breast Cancer Prevention Strategies
Breast Cancer Prevention Strategies
The National Cancer Act of 1971 was established when then President Nixon declared the "war on cancer." Since that time, no magic bullet has been discovered, and it is apparent that we have not been victors in the war against the nation's second leading killer. Overall cancer rates have continued to rise, with only a slight decrease in mortality from breast and other cancers. Nevertheless, remarkable progress has been made in the cure of childhood cancers, Hodgkin's disease, and testicular cancer.[1,2]
The US Department of Health and Human Services has now established year 2000 objectives focusing on cancer prevention and control through utilization of health education measures to change high-risk behaviors and promote screening and early detection. The ultimate goal of these initiatives is a reduction in the incidence of and morbidity and mortality from cancer.
Since the war on cancer was declared, breast cancer has moved to the forefront of public, medical, and political interest. In 1996, an estimated 184,000 cases of breast cancer were diagnosed, and nearly 55,000 of these will prove fatal. Breast cancer is the most common malignancy in women and the second leading cause of cancer death after lung cancer. Prevention strategies include early detection, risk-factor modification, and chemoprevention.
In the past 2 years, great headway has been made in understanding the molecular and cell biology of breast cancer. Genes that predispose women to this cancer have been identified, and continuing efforts are aimed at understanding the implications of these discoveries with respect to prevention.
Only a small proportion of breast cancer, 5% to 10%, can be attributed to an inherited gene mutation. Thus, any prevention efforts aimed at identifying individuals at high risk due to genetic susceptibility will apply only to a small number of women and are unlikely to make a large impact on overall breast cancer rates.
The large international variability of breast cancer rates and the increased incidence observed in countries with previously low rates suggest that environmental exposures are important risk factors for the disease.[5,6] It has been suggested that childhood and adolescent nutritional patterns and energy balance may explain the disparate rates among countries.
Modifiable Epidemiologic Risk Factors
Epidemiologic risk factors have been studied extensively, and interest has focused on those variables that are amenable to change. Risk factors for breast cancer include: family history, age at menarche, age at menopause, age at first full-term pregnancy, parity, lactation, use of hormone replacement therapy, diet, obesity, alcohol consumption, radiation therapy, and physical inactivity. The effect of some of these variables on cumulative exposure to estrogen and progesterone appears to be important in determining risk.
From a public health standpoint, identifying lifestyle factors that are conducive to change and then motivating women to alter their behavior is important and will make an impact on a woman's risk of developing breast cancer. Unfortunately, some of these established risk factors for breast cancer are not reasonable candidates for modification.
Love and Vogel present a detailed overview of the biology of breast cancer with special emphasis on modifiable risk factors and chemoprevention. They identify risk factors that are appropriate targets for change and mention behavioral and social strategies as mechanisms for this change. Translation of current knowledge about modifiable risk factors and screening behaviors will play an extremely important role in the prevention of breast cancer. It is crucial that we conduct translational research focusing on how to motivate women to modify their behaviors and also measure these outcomes.
We agree with Love and Vogel that there needs to be a greater understanding of the biology of breast cancer. This should not overshadow the fact that a vast amount of data has already been accumulated on breast cancer, and a relationship has been established between specific epidemiologic risk factors and breast cancer. Particular emphasis should be placed on these factors, as well as differences in childhood and adolescent nutritional patterns, physical activity, and energy balance during the prepubertal or adolescent years.
Proactive strategies to reduce breast cancer risk include: increasing fruit and vegetable consumption, maintaining ideal weight, increasing physical activity levels, moderating alcohol consumption, encouraging lactation, and, possibly, smoking cessation. Breast self-examination and mammography screening are also important to ensure early detection.
Active Role of Providers in Patient Education
Women need to be educated about strategies for preventing breast cancer. Primary-care physicians, surgeons, and oncologists play an important role not only in detecting and treating cancer but also as conveyors of important public health information. They have the opportunity to make a direct impact on women because of their personal contact with them. Historically, we have seen an emphasis on treatment of advanced disease by these physicians, as compared with primary prevention of cancer. Health-care providers must take an active role in educating the public about prevention beyond diagnosing and treating the cancer.
1. Mettlin CJ: New evidence of progress in the National Cancer Program. Cancer 78:2043-2044, 1996.
2. Cole P, Rodu B: Declining cancer mortality in the United States. Cancer 78:2045-2048, 1996.
3. Shottenfeld D: Principles and applications of cancer prevention, in Shottenfeld D, Fraumeni, Jr. JF (eds): Cancer Epidemiology and Prevention, pp 1391-1409. New York, Oxford, 1996.
4. American Cancer Society: Cancer Facts & Figures--1996. Atlanta, American Cancer Society, 1996.
5. Henderson BE, Pike MC, Bernstein L, et al: Breast cancer, in Shottenfeld D, Fraumeni JF Jr (eds): Cancer Epidemiology and Prevention, pp 1022-1039. New York, Oxford, 1996.
6. Doll R, Peto R: The causes of cancer: Quantitative estimates of avoidable risks of cancer in the United States today. J Natl Cancer Inst 66:1191-1308, 1981.
7. Sporn MB: The war on cancer. Lancet 347:1377-1381, 1996.