Breast Cancer Control
Breast cancer control encompasses prevention, early detection, treatment and palliative care. Many of the risk factors are not modifiable (genetic factors, age of menarche and menopause) and others relatively difficult to modify (number of pregnancies). Others may be modifiable through the provision of information to women (e.g., duration of lactation, diet), while yet others are modifiable, but of uncertain importance (e.g., smoking). Anti-estrogens such as tamoxifen, Raloxifene and aromatase inhibitors have been shown to lower the risk of breast cancer in women at high risk, but are unlikely to be feasible in the bulk of wome in low and middle income countries. While women should be educated about the importance of these factors, it is important to realize that the results of treatment have steadily improved in recent decades, and early stage breast cancer is now potentialy curable in a high fraction of cases if treated efficiently (around 90% of women are alive at 5 years). Breast conservation is sometimes possible in women with very limited disease confined to the breast. Thus, national cancer control programs should give breast cancer, the most common cancer in women at a global level, a high priority. This applies particularly to Muslim countries, where breast cancer incidence is many times higher than cervical cancer and may account for as many cases as several of the next most common cancers put together. Even in these countries, however, the incidence of breast cancer is much lower than in high income countries - a factor that is important in deciding upon cancer control activities.
It is not easy to determine the optimal approach, or set of combined approaches that will be used to control breast cancer. Prevention may be combined with general approaches that relate to many other cancers and non-communicable diseases in general, e.g., encouraging a healthy diet and tobacco control, and breast feeding should also be encouraged for many different reasons. A major element of breast cancer control derives from the observation that a much higher fraction of breast cancer patients in low and middle income countries have advanced stage than is the case in high income countries. Thus, early diagnosis followed by prompt, effective treatment, is the key to successful breast cancer control.
Early Detection of Breast Cancer
Several approaches should be considered with respect to early detection - educational programs are possible in all countries, and education combined with screening either by self or clinical breast examination (BE) and or mammography. The feasibility of screening will vary with respect to socioeconomic circumstances and both the resources available for health care and the health care structure. However, given that breast cancer is increasing in incidence throughout the world, it may be reasonable to establish pilot programs in defined regions with realistic 5 and 10 year targets with respect to the number of women screened. Such studies should be performed only after performing a situational analysis) and should always be accompanied by the collection of sufficient information about the program to allow evaluation, including cost effectiveness. Such pilot programs, if they prove to be cost effective and feasible in a wider geographical context, could provide a platform on which population coverage could be increased as the incidence of breast cancer rises. It is important to recognize that the value of mammographic screening in high income countries is controversial. While most believe that it does reduce mortality, possibly by 15-20%, this benefit must be balanced by an overdiagnosis and overtreatment rate estimated to be 30%. According to a recent Cochrane review "for every 2000 women invited for screening throughout 10 years, one will have her life prolonged. In addition, 10 healthy women, who would not have been diagnosed if there had not been screening, will be diagnosed as breast cancer patients and will be treated unnecessarily." This data comes from high income countries, and must be interpreted in that light. In fact in countries where there is a lower incidence of breast cancer, once prevalent cases have been detected, even more women would have to be screened to prolong one life and misdaiagnosis rates may be higher, so that the possibility for doing more harm than good must be taken very seriously. Because treatment for breast cancer has improved significantly in recent decades, while early diagnosis remains important, it may be much less important to detect preclinical disease - the major aim of mammography. It will be important to keep the case for breast cancer screening under constatnt review.
It should be recognized that there is, as yet, no evidence that breast examination (whether self BE or clinical BE) can lower mortality, and there is insufficient evidence to weigh the cost-benefit ratio. Studies from China, Russia and Canada have failed to show a benefit to self breast examination. Indeed, both self BE and clinical BE could be harmful in several ways - ineffectively using prescious resources for health care and unecessarily increasing interventions (most detected abnormalities ae more likely to be benign by a factor of perhaps 10) including imaging and biopsy, and of course, causing the patient and family unnecessary anxiety. Thus, it is the recommendation of the WHO that breast examination is not undertaken as an approach to early detection without evaluation of its effectiveness. These negative factors also apply to mammography.
Factors that Negatively Impact upon the Cost-Effectiveness of Screening Programs
Problems that have been shown to lessen the value of breast cancer control include refusal of diagnostic or therapeutic interventions in screen positive women which also occurs in a fraction of unscreened women who present with a breast mass. Even mammography, that is generally considered to be an effective method of early detection may lose a considerable part of its value in highly aware women, and estimates of the relative contributions of mammography versus improvements in treatment to recent reductions in mortality rates are difficult to calculate. Disadvantages of mammography include the need for skilled mammographers and mammography technicians as well as mammography equipment. The contribution of digital mammography, permitting reading at another site is unknown, but could make mammography more feasible in circumstances where human resources remain limited.
Age-Specific Incidence of Breast Cancer in Low and Middle Income Countries
It is important to recognize that the pattern of breast cancer, e.g., with respect to age-specific incidence, differs in low and middle income countries as well as Japan, where the continuing increase in the incidence of breast cancer after menopause is not apparent in age-specific incidence curves. The resultant lower mean age of women with breast cancer is often misinterpreted as indicating that breast cancer has a higher incidence in young women in low and middle income countries. That this is not the case is particularly well shown in the WHO Eastern Mediterranean Region, where it is clear that the lower crude incidence at all ages in this region is reflected in a reduced incidence in both young women up to the age of 44 years as well as in women aged 45 and above. Since such curves depend upon 5 year age groups, they are not a consequence of the age structure of the population - another frequent misinterpretation of the data. These findings have implications for the efficacy of screening and the optimal approach, as well as for the cost-benefit ratio (since the lower the incidence, the more women must be screened to detect a single cancer - but many patients will have abnormalities requiring investigations, that will prove to be benign). These graphs also demonstrate that the age specific mortality rates (crude) are higher in younger women in the Eastern Mediterranean Region in spite of the lower incidence of breast cancer - presumably largely a consequence of the later stage at presentation, but also, perhaps, reflecting higher rates of treatment refusal or less effective treatment.
A bibliography with links to Medline on breast cancer control in developing countries is available.
Model Data Collection Forms
A set of modules is provided that can be used to collect relevant data in a structured program in which the effectiveness of breast cancer control can be evaluated, regardless of whether early detection is accomplished by breast examination or mammography. It is assumed that data will be entered into a web-based system at participating clinics (whether community or hospital based) and hospitals, but completed data forms could also be hand carried or sent by mail or e mail to the data center. The modules cover education received, accessing care, early detection, diagnostic work up, treatment and treatment outcome. A module for women presenting at a treatment facility in the absence of screening of any kind is also provided. Thus, in a given cancer institute where referrals will come from screening clinics on the one hand, and will be presenting without screening on the other, the stage and treatment outcome of the two groups can be compared. An outline of this approach in which multiple screening clinics refer screen positive patients to referral hospitals for diagnosis and treatment is provided in the form of a PowerPoint presentation. A separate A4 size diagrammatic summary of implementation and management plans is also available in PowerPoint format.
These modules provide templates which can be modified to suit the needs of specific situations in different countries. The attached files are still in the draft stage. Not all the modules may be required in individual studies (e.g., epidemiological studies, detailed family histories) but are available in case the collection of such information is required.
Module 1: Identifiers and Demographics
Module 2: Education
Module 3: Recruitment
Module 4: Clinical Breast Examination
Module 5: Mammography
Module 6: Diagnostic Work-up Screen Positive
Module 7: Referral - no screening
Module 8: Consultation; not screened
Module 9: Pathology
Module 10: Epidemiology
Module 11: Family History; females
Module 12: Family History; males
Module 13: Past History
Module 14: Disease Sites
Module 15: Stage
Module 16: Receptor Status
Module 17: Treatment
Module 18: Treatment Response
Module 19: Summary - Overview
Module 20: Summary - Screening Center
Module 21: Summary - Diagnostic Center
Module 22: Summary - Treatment Center