UICC World Cancer Congress 2006

Objective: The early detection of cancer encompasses the detection of cancer in individuals who exhibit signs and symptoms in the evolution of the disease, as well as the detection of cancer (or precancerous lesions) in apparently healthy populations. Thus, early detection programs for cancer have two components: 1) early diagnosis, based on awareness (by the public or health professionals) of the signs and symptoms of cancer which can result in substantial improvement in the outcome of persons destined to develop cancer if they are adequately treated; 2) screening, based on the presumptive identification in an apparently asymptomatic population of either precancerous lesions or very early stage cancers by means of tests, followed by effective treatment for the lesions detected. Both approaches involve costs to the individual (in terms of time spent, distance travelled, possible cash payments for detection/diagnosis) and the health services (manpower, subsidies for detection/diagnosis, treatment, follow-up), and may be associated with undesired harm. It is important to establish that the benefits of early detection outweigh complications and harmful effects before implementation of one or the other type of early detection as a cancer control policy. Thus a decision to implement early detection of cancer should be evidence-based, depending on the burden of the disease, efficacy and cost-effectiveness of each early detection solution and the level of development of health services in a given setting. The latter is particularly important in low resource settings, as the whole process may involve substantial costs and risk diversion of resources from other health-care activities. It is important to bear in mind that interventions for the early detection of cancer can help reduce mortality from cancer only if they are part of a wider cancer control strategy that offers individuals appropriate diagnostic procedures and effective treatment and follow-up. These activities need to be integrated at appropriate levels of health services and specific additional investments in health service infrastructure are required to cater for the additional cases resulting from early detection

Methods: For breast cancer there are effective methods of early detection and treatment, but their implementation in developing countries has been uneven because of such countries' resource limitations. Early diagnosis: Increasing awareness among the general public and health care providers of the warning signs and symptoms of breast cancer is the basic tool for early diagnosis. People should be educated to understand that cancer, when diagnosed early, is far more likely to respond to effective treatment. Substantial endeavours may be needed in many cultures to dispel the myths, fears and gloom that tend to accompany any consideration of cancer. The program needs to ensure that health care workers are trained to recognize early cancer cases and refer patients rapidly to places where the disease can be diagnosed and treated. Such workers must be systematically trained so that they are alert to the signs and symptoms of early cancer, though their prior training may have only exposed them to advanced and often untreatable cancers. For the early diagnosis of breast cancer the Clinical Breast Examination (CBE) is the method of choice, so it is of the utmost importance to extensively trained health care workers to adequately perform this technique. It may be necessary to improve peoples' accessibility to trained health workers competent to perform the necessary examinations (including female health workers). It is critical that every suspected case of cancer is promptly referred for appropriate diagnosis and therapy, and that institutions with the staff and facilities necessary to provide effective treatment are identified and accessible to patients. Endeavour should be taken to avoid financial barriers to diagnosis and treatment. Breast Cancer Screening: Screening methods for early detection of breast cancer include screening mammography; clinical breast examination (CBE), and breast self-examination (BSE). Screening by mammography, clinical breast exam, or both may decrease breast cancer mortality, but there is uncertainty about the magnitude of the benefit because of the inconsistency of results across studies, ranging from no reduction in breast cancer mortality to a 30% reduction in breast cancer mortality among women age 50 and above from mammography screening (1). A CBE is an examination of the breast performed by trained health care professionals. Advocates of CBE point to evidence from the Canadian National Breast Screening trials (2) that indicated equivalent results for CBE alone when compared to CBE plus mammography. Clinical breast examination, when adequately performed, may be of particular importance in countries where there are insufficient resources for mammography and where disease is usually at an advanced stage at the time of diagnosis. Breast self examination (BSE): two large randomized studies of organized programs to instruct women in BSE have yield disappointing results (1,3).

Results: How to decide if an early detection and/or screening component is needed in a country? A country should only introduce an early detection programme if a number of pre-requisites have been fulfilled: 1. What is the cancer burden in the country? the target disease should be a common form of cancer, with high associated morbidity and/or mortality; 2. Are accurate diagnosis and effective treatment, capable of reducing morbidity and mortality, available and accessible to all? 3. What proportion of cases presents with potentially curable cancer? (stage at diagnosis), 4. Are there already programmes for early detection (either early diagnosis or screening) working and evaluated? After reviewing the listed information, a necessity to implement or to modify either early diagnosis or screening program can be defined. - If the majority of breast cancers are advanced at presentation (i.e. stage III or IV), it is necessary to promote measures for earlier diagnosis and referral. Early diagnosis should result in the diagnosis of a cancer at an earlier, more treatable stage. Therefore the main objective of early diagnosis programmes is to promote the downstaging of cancers, their diagnosis in a smaller, potentially less advanced (in terms of spread to other organs) stage. Because of this, it is important to support the collection of data on stage for decisions on appropriate treatment. Such data are usually available in patients' clinical charts. It is important to recognise that identification of cancers at an early stage, with their referral, and treatment, is of far greater prognostic importance than any attempts to treat the disease in its late stages. Even in cases where the eventual outcome cannot be changed, treatment is simpler and quality of life improved. Individuals with symptomatic cancers are many fewer than the numbers that would have to be included in screening programmes directed to asymptomatic people. Therefore in planning how relatively scarce resources can be most optimally used, it should be recognised that it will initially be more cost-effective to concentrate on early diagnosis rather than screening. The success of the programme is determined by the participation rate which influences the extent cases are diagnosed at less advanced stages (e.g. a change in the mean diameter of breast cancers from 5 cm to 3 cm or less). At a later date it should be possible to demonstrate the decrease in mortality.

- Fundamental to the success of a screening programme is that: 1. The test procedures should be acceptable, safe, and relatively inexpensive. Physical examinations of the breast require dedicated examination rooms, but the facilities required for mammography are substantial. 2. Some mechanism has to be found to bring the target population into screening. It will be necessary to hire staff to actively recruit potential women. 3. A quality control programme should be organised to insure low medical and economical cost. Although many means to assure quality of screening tests can be instituted in laboratories, quality is also required in their administration, and in assuring those with positive screening tests attend for diagnosis and treatment following them. Appropriate facility for diagnosis will vary depending on the condition for which screening is designed. For breast cancer, fine needle aspiration biopsy or open (excisional) biopsy may be required, which will require as a minimum an experienced surgeon and an experienced (cyto)pathologist. For those treated, follow-up continues to ensure there are no complications of treatment, or that further treatment is not required. 4. Mechanisms to recall women for re-screening. For breast cancers, full benefit from screening will only follow if tests at appropriate intervals are realised. For CBE, this interval is yearly, for mammography screening, the interval is 2 years. WHO did not recommend that developing countries implement screening for breast cancer, because it believes that, the focus for any screening efforts should be on cytological screening (Pap tests) for cervical cancer. Other resources should be devoted to palliative care or diagnosis and treatment (4). Similarly, the Global Summit Early Detection Panel concluded that mammographic screening is not currently a realistic goal for most countries with limited resources and recommended that early detection efforts first be focused on the education of patients and physicians and increasing general social awareness about breast cancer. The Summit Panel suggested the following sequential approach: 1) promote the empowerment of women to obtain health care, 2) develop the infrastructure to diagnose and treat breast cancer, 3) begin early detection efforts through breast cancer education and awareness, and 4) when resources permit, expand early detection efforts to include mammographic screening if breast cancer treatment is available for all detected cancer. The Panel argued that although such programs will first provide care to a portion of the population and could serve as pilot programs for more extensive programs covering larger populations, and ultimately the entire population, as resources becomes available (6). Conclusion Both early detection approaches involve costs and may be associated with undesired harm. It is important to establish, in each specific country's context, which strategy will be the most appropriate to increase the benefits, at the lower cost: i.e. more rapidly decrease the breast cancer mortality and improve the quality of life for those diagnosed with breast cancer. This can be achieved by performing a situation analysis mostly based on demographic, economic and epidemiological data.

References 1. IARC Handbooks on Cancer Prevention, Vol 7, Breast cancer screening. Lyon, IARC Press, 2002. 2. Miller AB., Baines C.J, Wall C. (2000) Canadian national Breast Screening Study-2 :13 year results of a randomized trial in women age 50-59 years. J.Natl Cancer Inst., 92:1490-1499 3. Pisani P, Parkin DM, Ngelangel C et al. Outcome of screening by clinical examination of the breast in a trial in the Philippines. Int J Cancer 2006; 118:149-154. 4. Strong K, Wald N, Miller A, Alwan A, on behalf of the WHO Consultation Group. Current concepts in screening for non communicable disease: World Health Organization Consultation Group Report on methodology of non communicable disease screening. J Med Screen 2005; 12:12-19. 5. Anderson BO et al., Breast cancer in limited-resource countries: Health Care systems and public policy; the Breast journal 2006;12-1:S54-S69.