In April, the World Health Organization (WHO) released the World Cancer Report, announcing that cancer rates could further increase by 50% to 15 million new cases in the year 2020. "We have the opportunity to stem this increase," said Paul Kleihues, M.D., director of the WHOs International Agency for Research on Cancer and co-editor of the report. "Action now can prevent one-third of cancers, cure another third, and provide good, palliative care to the remaining third who need it."
How can the WHO predict what cancer rates will be in 17 years? And why is Kleihues confident of the percentage of cancers that could be prevented and cured? Organizations such as the WHO, the National Cancer Institute, and the American Cancer Society have made predicting the future into a planning tool. These organizations use predictions to allocate resources and develop guidelines.
Predicting the future cancer burden is one of the first steps in knowing how to allocate resources most effectively. "In terms of research priorities, this has been an ongoing perennial discussion. In funding too, the burden of cancer is considered an important index of priority," said Martin L. Brown, Ph.D., chief of the Health Services and Economics Branch of NCIs Division of Cancer Control and Population Sciences. Brown pointed out that data from the Surveillance, Epidemiology, and End Results (SEER) program show that the most prevalent cancer sites are prostate, lung, breast, and colon/rectum. "Does that determine research funding priorities?" Brown asked. "I think to some degree it does. I dont think its absolutely a one-to-one relationship."
|
The WHO has noted a similar trend, magnified by societal changes in developing countries. "Some of us . . . were seeing a clear transition in large developing countriessmall ones too for that mattertoward much older populations, the result of fertility decline and changed age distribution of populations," said Dean Jamison, Ph.D., a fellow in the Division of Advanced Studies and Policy Analysis at the Fogarty International Center at the National Institutes of Health. "And then as time goes on theres this so-called epidemiological transition, which leads to the patterns of cause of death across nations in developing countries looking more and more like high-income countries."
This epidemiological transition stems from a shift in developing countries to morbidity and mortality now resulting primarily from non-communicable illnesses rather than from infectious diseases as was more common in the past. "In 2003, chronic disease and cancer [are] now the dominant causes of death and disease in five of six regions of the world," said Derek Yach, M.D., Ph.D., executive director of WHOs Noncommunicable Diseases and Mental Health Cluster. The cluster uses this knowledge to focus its cancer control efforts on reducing tobacco use, improving diet and increasing physical activity, and encouraging early cancer detection. "We have focused our priorities on where the burden is greatest," said Yach.
Besides allocating resources, organizations use predictions to influence others to allocate or assign their own resources to fight cancer. The Disease Control Priorities Project, a joint effort by the WHO, the World Bank, and the NIH, uses WHOs projection of the cancer burden worldwide to spur research and to direct funding. Project leaders plan to publish a second edition of Disease Control Priorities in Developing Countries, a publication designed to compare the cost effectiveness of interventions created to address major causes of disease burden in developing countries. The new edition will include a chapter about cancer. Based on the increasing burden of cancer worldwide, the group is looking at alternatives to high-cost treatments for cancer used in more developed nations, such as long-term chemotherapy or radiation.
"My suspicion is that surgery, including some kinds of cancer surgery, is going to turn out to be pretty cost effective in developing country environments," said Jamison. "We havent looked at that in contrast to some medical interventions, such as chemotherapy, but well know more about that in the next year." The publication will partially be a how-to for groups funding health projects internationally.
In the United States, national and state projections help smaller health agencies allocate their resources. The American Cancer Society publishes Cancer Facts & Figures each year, which offers projections of the current years cancer incidence and mortality based on SEER data. "SEER has been there for a long time and is the gold standard," said Ahmedin Jemal, Ph.D., program director for Cancer Occurrence in the American Cancer Societys Department of Epidemiology and Surveillance Research. The projections are used by the organization to encourage cancer control, including stimulating funding for research and focusing prevention efforts. "The data is for the states for cancer control purposes, for the media to promote cancer control, and for legislators," said Jemal.
Beyond population-level predictions of overall cancer rates, predictions of reductions in cancer mortality based on early detection efforts have helped organizations formulate guidelines on cancer screening. Published guidelines for breast, cervical, and colorectal cancer screening, among others, by organizations such as the U.S. Preventive Services Task Force make use of research that predicts a persons chances of developing cancer based on the presence or absence of known risk factors. For cervical cancer, this might be a verified abnormal result on a yearly Pap smear; for colorectal cancer, the presence of colon polyps.
The WHO Framework Convention on Tobacco Control shows one possible effect of future projections. On May 21, 192 WHO member states ratified the first international treaty negotiated under the auspices of the WHO, agreeing to reduce the prevalence of tobacco use and exposure to tobacco smoke. The treaty is based on the projection that the number of tobacco-related deaths, which now stands at 5 million per year globally, will double by 2020. "The impact on cancer will be profound," Yach said of the new treaty.
Ultimately, researchers hope that predicting future cancer rates can spur and direct international action. The World Cancer Report is a prime example. "The report provides a basis for public health action and assists us in our goal to reduce the morbidity and mortality from cancer, and to improve the quality of life of cancer patients and their families everywhere in the world," said Gro Harlem Brundtland, M.D., WHO director-general.
In the next issue: How do organizations such as WHO and NCI go about predicting cancer rates? The News will examine different programs and look at different ways that organizations measure progress in cancer control.
![]() |
||||
|
Oxford University Press Privacy Policy and Legal Statement |