Cancer control: introduction to a series of reports on strategies and approaches

Bulletin of the World Health Organization, 64 (1): 69-71 (1986) © World Health Organization 1986 Cancer control: introduction to a series of reports on strategies and approaches J. STJERNSWARD,l K. STANLEY,2 & I. C. HENDERSON3 No search for new treatments of cancer or new preventive measures can realistically hope to offer benefits anywhere near as large as those that can be gained by the wider application of current knowledge. A series ofpapers on strategies in cancer control, to be published in the Bulletin of the World Health Organization, will describe thefoundations and approaches that can significantly reduce morbidity and mortality from cancer. Commencing with this issue of the Bulletin of the World Health Organization, a series of papers on cancer control strategies will appear in this journal; they will be concerned with primary prevention and early detection of cancer, cost-effectiveness of ap- proaches, and health education, and will review the state of the art in the control of some common cancers. The initial article in this series (see p. 73) considers the five phases of a systematic approach to cancer control, which will prevent premature accep- tance of unproven hypotheses and inappropriate consumption of limited health care resources. A GROWING PROBLEM Cancer is increasingly recognized as an important public health problem worldwide. The latest global statistics on cancer released by the World Health Organization show that in absolute numbers there are now more cases and deaths from cancer in the Third 1 Chief, Cancer Unit, World Health Organization, 1211 Geneva 27, Switzerland. Requests for reprints should be sent to this address. 2 Scientist, Cancer Unit, WHO, Geneva, Switzerland. 3Associate Professor of Medicine, Harvard Medical School and Dana-Farber Cancer Institute, Boston, MA, USA. World than in the industrial countries (1, 2). After the age of five years, cancer is one of the three most frequent causes of death in both developed and de- veloping countries (3). According to present trends, the incidence of cancer will continue to rise in many developing countries because of increases in life expectancy and in the consumption of tobacco, and a reduction in mortality from infectious diseases. It is unrealistic to expect that resources for cancer treat- ment will increase markedly in the near future. How- ever, the cancer problem can be dramatically reduced with the available resources by setting the right. priorities (4). Approaches are available to prevent a third of all existing cancers, to cure another third (if the cases are detected early enough and adequate therapy is provided), and to ensure that virtually all cancer patients are spared pain. The need for new priorities and strategies, even in developed countries, was indicated by recent data on mortality from cancer in 28 industrial countries (5). This analysis showed an overall increase of death rates from cancer by 55% in males and 40% in females from 1960 to 1980. The most dramatic rise in age-adjusted mortality was registered for lung cancer, 76% for men and 135% for women, which confirms the urgency for action against tobacco use. 4637 -69 J. STJERNSWARD ET AL. It is clear that existing knowledge in this area has not been exploited very effectively. In these developed countries, the limited impact on overall cancer mortality by therapy alone (for most cancers) and the clear reduction in cervical cancer mortality in countries with adequate screening programmes are indications for the proper setting of priorities in national control efforts. PRIORITIES FOR CANCER CONTROL A method for setting priorities for cancer control programmes has been developed by WHO. It com- pares the effectiveness and costs of various cancer control activities by providing a structure and language so that each element can be addressed separately and then recombined to estimate the impact of different activities. This method is currently being tested in selected countries and will be reviewed later in this series. Primary prevention offers the greatest hope for reducing the number of deaths caused by some cancers. Further, the measures aimed at preventing cancer sometimes also reduce morbidity and mortality caused by other diseases; for example, a reduction in tobacco consumption would not only substantially diminish the cancer problem, but also reduce cardiovascular and respiratory diseases. Approximately 90/o of lung cancers in developed countries are caused by the smoking of cigarettes (6). There is a strong dose-response relationship and the risk is greater among those who start smoking at an early age. Anti-tobacco legislation, education and information on tobacco and health, and coordinated national tobacco control efforts have been recom- mended by WHO as the best approach to reducing mortality from lung cancer, which is currently the second most common cancer worldwide and could soon become the most common (1). A major health problem in south-east Asia is oral cancer with more than a hundred thousand new cases each year. Approximately 90%o of oral cancers in this region are caused by local forms of tobacco chewing and smoking. Early detection of this cancer by pri- mary health care workers has been shown to be feasible (9). A health education programme in India has demonstrated that it is possible to reduce the number of persons with this habit, the number of pre- cancerous lesions, and the disease itself (7). In the developing countries about 80/o of liver cancer cases evidently result from infection with hepatitis B virus (8). Effective vaccines have been developed, but they are still too costly for use in the Third World; when cheaper vaccines become avail- able they will play an important role in reducing not only the mortality from liver cancer which is especially high in parts of Africa and eastern Asia, but also chronic hepatitis which is a major health problem in these areas. Cancer of the uterine cervix is the most common in developing countries and is the second most common cancer worldwide in women, with approximately half a million new cases each year. Decreases of 50-60% in cervical cancer mortality have been observed in countries where cytological screening has been under- taken in a well-organized fashion. However, even though extensive knowledge on the conduct and value of cytology screening is available, it has not been applied optimally in many locations, and not even minimally in others. Strategies are being formulated to ensure establishment of early detection approaches which cover the women at risk, to ensure adequate cytological services, and to provide appropriate therapy to the identified cases. For example, in countries where resources are limited, the aim should be to screen every woman once in her lifetime be- tween 35 and 50 years of age. When more resources are available and every woman has been covered at least once, the frequency of screening can be increased and the age range extended in a stepwise fashion. A detailed report of these approaches will also be pre- sented in this series. Mammography and clinical examination, with or without self-examination of the breasts, have gen- erally proved effective in the early detection of breast cancer (10). In many countries, however, self-exam- ination will probably be the only feasible approach to wide population coverage for a long time to come.. Its effectiveness as a single measure has not yet been determined, but controlled studies are proceeding. At present, in most countries, cancer control act- ivities lack overall coordination. Guidelines for the formulation of national cancer programmes have been developed to assist countries in realistically deal- ing with cancer problems using the available limited resources. The recommended approach involves assessing the existing situation, defining health objec- tives, evaluating possible control strategies, and setting priorities on the basis of quantitative assess- ments (4). No search for new treatments of cancer or new preventive measures can, in the foreseeable future, realistically hope to offer benefits anywhere near as large as those that can be gained by the wider appli- cation of current knowledge. This series of papers on strategies in cancer control will therefore describe the foundations and approaches that can significantly reduce morbidity and mortality from cancer. 70 CANCER CONTROL STRATEGIES 71 RESUME LUTTE ANTICANCEREUSE: INTRODUCTION A UNE SERIE D'ARTICLES SUR LES STRATEGIES ET LES APPROCHES Dans le present numero du Bulletin de l'Organisation mondiale de la Sante, commence la publication d'une serie d'articles sur la lutte anticanc6reuse qui auront trait a la pre- vention primaire et au depistage precoce du cancer, aux approches cofit/efficacite et a l'education pour la sante. On y fera egalement le point des possibilites actuelles en matiere de lutte contre certains cancers frequents. Le premier article de cette serie examine les cinq phases d'une nouvelle approche systematique de la lutte anticancereuse qui evitera d'admettre un peu trop rapidement des hypotheses non veri- fiees et d'employer inopportun6ment des moyens limites d'action sanitaire. Actuellement, dans la plupart des pays, la lutte anticance- reuse manque de coordination d'ensemble. Des directives applicables a la formulation de programmes nationaux de lutte anticancereuse ont e elaborees afin d'aider les pays a faire face de facon realiste aux problemes que pose le cancer en se servant des moyens limites dont ils disposent. L'approche recommand&e consiste a evaluer la situation existante, a definir des objectifs sanitaires, a evaluer des strategies eventuelles de lutte, et a fixer des priorites sur la base d'appreciations quantitatives. On ne saurait serieusement esperer que les recherches en vue de nouveaux traitements ou les mesures nouvelles de pr6vention puissent, dans un avenir previsible, donner des resultats d'ampleur presque aussi grande que ceux sus- ceptibles d'etre obtenus par une application plus etendue des connaissances actuelles. En consequence, cette serie d'articles sur les strategies de lutte anticancereuse exposera les principes de base et les approches qui peuvent continuer a reduire sensiblement la morbidite et la mortalite par cancer. REFERENCES 1. PARKIN, D. M. ET AL. Estimates of the worldwide frequency of twelve major cancers. Bulletin of the World Health Organization, 62: 163-182 (1984). 2. Cancer as a global problem. Weekly epidemiological record, 59: 125-126 (1984). 3. WORLD HEALTH ORGANIZATION. Sixth report on the world health situation, 1973-1977. Part I, Global analysis. Geneva, 1980. 4. STJERNSWARD, J. ET AL. Cancer control: strategies and priorities. World health forum, 6: 160-164 (1985). 5. Cancer in developed countries: assessing the trends. WHO Chronicle, 39: 109-111 (1985). 6. A WHO MEETING. Reappraisal of the present situation in prevention and control of lung cancer. Bulletin ofthe World Health Organization, 60: 809-819 (1982). 7. AWHO MEETING. 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