Facts ,diet and physical activity's impact
- Cancer accounts for 7.1 million deaths annually (12.5% of the global total).
- Dietary factors account for about 30% of all cancers in Western Countries and approximately up to 20% in developing countries; diet is second only to tobacco as a preventable cause. Approximately 20 million people suffer from cancer; a figure projected to rise to 30 million within 20 years.
- The number of new cases annually is estimated to rise from 10 million to 15 million by 2020.
- More than half of all cancer cases occur in developing countries.
Cancer is becoming an increasingly important factor in the global burden of disease. The estimated number of new cases annually is expected to rise from 10 million in 2000 to 15 million by 2020. Some 60% of these cases will occur in the less developed parts of the world. More than 7 million people now die each year from cancer. Yet with the existing knowledge, at least one-third of cancer cases that occur annually throughout the world could be prevented.
While tobacco use is the single largest causative factor -accounting for about 30% of all cancer deaths in developed countries and an increasing number in the developing world – dietary modification and regular physical activity are significant elements in cancer prevention and control. Overweight and obesity are both serious risk factors for cancer. Diets high in fruit and vegetables may reduce the risk for various types of cancer, while high levels of preserved and/or red meat consumption are associated with increased cancer risk.
What is cancer?
Cancer is used generically for more than 100 different diseases, including malignant tumours of different sites, such as breast, cervix, prostate, stomach, colon/rectum, lung and, mouth. Other examples of cancer are leukaemias, sarcomas, Hodgkin´s disease and non-Hodgkin´s lymphomas. The disease arises principally as a consequence of individual exposure to carcinogenic agents in what individuals inhale, eat and drink, or are exposed to in their personal or work environment. Personal habits, such as tobacco use, dietary and physical activity patterns - as well as occupational and environmental conditions - rather than genetic factors, play the major roles in the development of cancer.
Extent of the problem
Many of the chronic disease risks, and the diseases themselves, overlap. In developed countries, cancer is the second-biggest cause of death after cardiovascular disease (CVD), and epidemiological evidence points to this trend emerging in the less developed world. This particularly true in countries of "transition" or middle income countries, such as in South America and Asia. Already more than half of all cancer cases occur in developing countries.
There are approximately 20 million people living with cancer at the moment; by 2020 there will be an estimated 30 million. And the impact is far greater than the number of cases alone would suggest. Regardless of prognosis, the initial diagnosis is often perceived by patients as life-threatening, with over one-third of sufferers experiencing clinical anxiety and depression. Cancer can also be profoundly distressing as well as economically disruptive to patients' families. The clinical care of cancer patients is a costly element in public health budgets.
Diet and physical activity's impact
Dietary factors are estimated to account for approximately 30% of cancers in western countries, making diet second only to tobacco as a preventable cause of cancer. This proportion is thought to be about 20% in developing countries and is projected to grow. As developing countries become urbanised, patterns of cancer, particularly those most strongly associated with diet and physical activity, tend to shift towards the patterns of economically developed countries. Cancer rates also change as populations move between countries and adopt different dietary patterns.
The relative importance of cancers as a cause of death is increasing. The incidence of lung cancer and cancers of the colon and rectum, breast and prostate, generally increases in parallel with economic development, as stomach cancer declines. Cancer is also strongly associated with social and economic status. Cancer risk factors are highest in groups with the least education. In addition, patients in the lower socioeconomic classes have consistently poorer survival rates than those in higher strata.
In recent years, substantial evidence has pointed to the link from overweight and obesity, to many types of cancer such as oesophagus, colorectum, breast, endometrium and kidney. The composition of the diet is also important since fruit and vegetables may have a protective effect by decreasing the risk for some cancer types such as oral, oesophageal, gastric and colorectal cancer.
Regular physical activity has also been seen to have a protective effect in reducing the risk of breast and colorectal cancer. High intake of preserved meat or red meat might be associated with increased risk of colorectal cancer. Another aspect of diet clearly related to cancer risk is the high consumption of alcoholic beverages, which convincingly increases the risk of the oral cavity, pharynx, larynx, oesophagus, liver and breast cancers.
What can be done?
The wealth of knowledge that already exists about cancer risk factors provides obvious and ample scope for action to reduce the cancer burden of all countries. After tobacco, overweight and obesity seems to be the most important avoidable cause of cancer.
Given that poor nutrition, physical inactivity, obesity, tobacco and alcohol, are risk factors common to other chronic diseases, such as CVD, type 2 diabetes, and respiratory diseases, conducting a cancer prevention programme within the context of an integrated chronic disease prevention programme would be an effective national strategy.
Dietary factors that convincingly increase risk are:
- Overweight and obesity,
- Excess alcohol consumption (more than 2 units a day)
- Some forms of salting and fermenting fish
- Very hot (thermally) salty drinks and food
- Aflatoxins (fungal contaminants sometimes found on foods such as grains, peanuts, tree nuts, and cottonseed meal)
||Physical activity (colon, breast)
||Overweight and obesity (oesophagus, colorectum, breast, endometrium, kidney)
||Fruit and vegetables (oral cavity, stomach, colorectum).
||Preserved meat (colorectum) oesophagus. Salt-preserved foods and salt (stomach). Very hot (thermally) drinks & food (oral cavity, pharynx, oesophagus
||Fibre, soya, fish, n-3 fatty acids, carotenoids, vitamins B2, B6, folate B2, B6, folate, B12, C,D, E, calcium, zinc, selenium,non-nutrient plant constituents, (eg allium, lignans, compounds, flavnoids, isoflavones)
||Animal fats, heterocyclic amines, polycyclic aromatic hydrocarbons, nitrosamines
Cancer is the uncontrolled growth and spread of cells that may affect almost any tissue of the body. Lung, colorectal and stomach cancer are among the five most common cancers in the world for both men and women. Among men, lung and stomach cancer are the most common cancers worldwide. For women, the most common cancers are breast and cervical cancer.
More than 11 million people are diagnosed with cancer every year. It is estimated that there will be 16 million new cases every year by 2020. Cancer causes 7 million deaths every year—or 12.5% of deaths worldwide.
We now know enough about the causes of cancer to prevent at least one-third of all cancers. Cancer is largely preventable: by stopping smoking, providing healthy food and avoiding the exposure to carcinogens. Information is also available that would permit the early detection and effective treatment of a further one-third of cases. Some of the most frequent cancer types are curable by surgery, chemotherapy or radiotherapy. The chance of cure increases substantially if cancer is detected early. There are effective strategies for the relief of pain and the provision of palliative care to all patients and their families, even in low resource settings.
Cancer control is a public health approach aimed at reducing causes and consequences of cancer by translating our knowledge into practice. WHO's work towards the prevention and control of cancer focuses on these major areas:
- promotion and strengthening of comprehensive national cancer control programmes,
- building international networks and partnerships for cancer control,
- promotion of organized, evidence-based interventions for early detection of cervical and breast cancer,
- development of guidelines on disease and programme management,
- advocacy for a rational approach to effective treatments for potentially curable tumours,
- support for low-cost approaches to respond to global needs for pain relief and palliative care.
The Cancer Programme is a key activity within the Department of Chronic Diseases and Health Promotion.
The burden of cancer is growing and 24.6 million people are presently living with cancer with more than half living in developing countries. Nearly 7 million people die each year of cancer. Cancer represents a tremendous burden on patients, families, and societies. It is one of the leading causes of death in the world and is still increasing, particularly in developing countries. Around 43% of cancer deaths are due to tobacco use, unhealthy diet, and infection.
However, 2 million lives can be saved by 2020 if appropriate measures are put in place to prevent, early detect, cure and care. This advocacy brochure describes the rising trend of cancer cases worldwide and the need to take a concerted action against cancer.
Almost all children with cancer will experience pain - as a direct result of the disease, as a side-effect of treatments or invasive clinical procedures, or as an aspect of psychological distress. In more than 70% of cases, that pain will at some stage become severe. Although means to relieve pain are widely available, in developed and developing countries alike, their use in children has often been very limited. Fears of drug "addiction", lack of knowledge of children's perception of pain and illness, use of inappropriate drug doses, and failure to understand the value of supportive, non-drug measures have all contributed to widespread inadequacy in the control of pain in children with cancer.
Incurable diseases cause the death of tens of millions of people every year, mostly in developing countries. While it is unlikely that this situation will change significantly in the short term, there is much that can be done to relieve the suffering that is an inevitable feature od such disease. Complementing the WHO's guidelines on the management of cancer pain, now in a second edition, this book is aimed at health professionals of all levels who are concerned with the care and comfort of patients with terminal diseases.
Cervical Cancer Screening in Developing Countries
This publication is the product of a comprehensive consultation undertaken by WHO in 2001, involving leading experts in the field of cancer epidemiology, screening and treatment. It is part of WHO's commitment to provide evidence-based guidelines to decision makers and a recognition of the priority that should be given to cervical cancer screening and treatment as an essential component of any comprehensive national cancer control programme. The report focuses particularly on the situation in low and middle income countries - countries in which cervical cytology screening may not be feasible or cost effective.
It documents the current state of evidence concerning alternative tests - Visual inspection with Acetic acid (VIA) and Human Papillomavirus (HPV) testing. It reviews trials that are currently being undertaken, and gives policy makers an indication of developments that are likely to emerge in the near future. However, it also emphasizes that the efficient and effective functioning of the system in its entirety is central to the success of any screening programme, irrespective of the screening method chosen.