Each year on 4 February, WHO and International Agency for Research on Cancer (IARC) supports International Union Against Cancer (UICC) to promote ways to ease the global burden of cancer. Preventing cancer and raising quality of life for cancer patients are recurring themes. WHO and IARC will focus this year on screening and vaccination.

Cancer is responsible for close to 13% of deaths worldwide, accounting for 7.6 million deaths in 2008. On World Cancer Day (4 February) this year, WHO is focusing on screening and vaccination. Increased access to cost-effective vaccinations to prevent infections associated with cancers and cost-effective cancer-screening programmes can help to reduce the number cancer deaths.

WHO and IARC promote screening and vaccination

Increased access to cost-effective vaccinations to prevent infections associated with cancers as well as the availability of cost-effective cancer-screening programmes for everyone can help to reduce cancer mortality.

Cost-effective vaccination prevents infections

Vaccination is available against cervical cancer, caused by the human papilloma virus (HPV) and liver cancer caused by the hepatitis B virus (HBV).

Cervical cancer

Cervical cancer is the second most common cancer in women worldwide and over 500 000 new cases are diagnosed every year. HPV vaccines are recommended for use in girls aged 9 to 13 years old and can prevent infection with HPV types 16 and 18, which are together responsible for approximately 70% of cervical cancer cases globally

Liver cancer

Liver cancer killed 700 000 people in 2008. Together, hepatitis B virus (HBV) and hepatitis C virus (HCV) account for 78% of liver cancer cases. A vaccine against hepatitis B has been available since 1982 and was the first vaccine against a major human cancer.

Early diagnosis reduces cancer mortality

Cancer mortality can also be reduced if cases are detected and treated early through early diagnosis and screening programmes. Early diagnosis is promoted by educating the public about early signs and symptoms of cancers. This is particularly relevant in low-resource settings where the majority of patients are diagnosed and treated in very late stages. Screening programmes use tests across a healthy population to detect signs for cancer or pre-cancer and allow to promptly refer affected persons for diagnosis and treatment. Effective screening programmes are for example available for breast cancer and for cervical cancer.

Cancer prevention

At least one-third of all cancer cases are preventable. Prevention offers the most cost-effective long-term strategy for the control of cancer.

Tobacco

Tobacco use is the single greatest avoidable risk factor for cancer mortality worldwide, causing an estimated 22% of cancer deaths per year. In 2004, 1.6 million of the 7.4 million cancer deaths were due to tobacco use.

Tobacco smoking causes many types of cancer, including cancers of the lung, esophagus, larynx (voice box), mouth, throat, kidney, bladder, pancreas, stomach and cervix. About 70% of the lung cancer burden can be attributed to smoking alone. Second-hand smoke (SHS), also known as environmental tobacco smoke, has been proven to cause lung cancer in nonsmoking adults. Smokeless tobacco (also called oral tobacco, chewing tobacco or snuff) causes oral, esophageal and pancreatic cancer.

• Tobacco and cancer: evidence and monitoring
• Implementation tools
• Tobacco Free Initiative

Physical inactivity, dietary factors, obesity and being overweight

Dietary modification is another important approach to cancer control. There is a link between overweight and obesity to many types of cancer such as oesophagus, colorectum, breast, endometrium and kidney. Diets high in fruits and vegetables may have a protective effect against many cancers. Conversely, excess consumption of red and preserved meat may be associated with an increased risk of colorectal cancer. In addition, healthy eating habits that prevent the development of diet-associated cancers will also lower the risk of cardiovascular disease.

Regular physical activity and the maintenance of a healthy body weight, along with a healthy diet, will considerably reduce cancer risk. National policies and programmes should be implemented to raise awareness and reduce exposure to cancer risk factors, and to ensure that people are provided with the information and support they need to adopt healthy lifestyles.

• WHO global strategy on diet, physical activity and health

Alcohol use

Alcohol use is a risk factor for many cancer types including cancer of the oral cavity, pharynx, larynx, oesophagus, liver, colorectum and breast. Risk of cancer increases with the amount of alcohol consumed. The risk from heavy drinking for several cancer types (e.g. oral cavity, pharynx, larynx and oesophagus) substantially increases if the person is also a heavy smoker. Attributable fractions vary between men and women for certain types of alcohol-related cancer, mainly because of differences in average levels of consumption. For example, 22% of mouth and oropharynx cancers in men are attributable to alcohol whereas in women the attributable burden drops to 9%. A similar sex difference exists for oesophageal and liver cancers (Rehm et al., 2004).

• Global strategy to reduce harmful use of alcohol

Infections

Infectious agents are responsible for almost 22% of cancer deaths in the developing world and 6% in industrialized countries. Viral hepatitis B and C cause cancer of the liver; human papilloma virus infection causes cervical cancer; the bacterium Helicobacter pylori increases the risk of stomach cancer. In some countries the parasitic infection schistosomiasis increases the risk of bladder cancer and in other countries the liver fluke increases the risk of cholangiocarcinoma of the bile ducts. Preventive measures include vaccination and prevention of infection and infestation.

• Infectious diseases health topics

Environmental pollution

Environmental pollution of air, water and soil with carcinogenic chemicals accounts for 1–4% of all cancers (IARC/WHO, 2003). Exposure to carcinogenic chemicals in the environment can occur through drinking water or pollution of indoor and ambient air. In Bangladesh, 5–10% of all cancer deaths in an arsenic-contaminated region were attributable to arsenic exposure (Smith, Lingas & Rahman, 2000). Exposure to carcinogens also occurs via the contamination of food by chemicals, such as afl atoxins or dioxins. Indoor air pollution from coal fires doubles the risk of lung cancer, particularly among non-smoking women (Smith, Mehta & Feuz, 2004). Worldwide, indoor air pollution from domestic coal fires is responsible for approximately 1.5% of all lung cancer deaths. Coal use in households is particularly widespread in Asia.

Occupational carcinogens

More than 40 agents, mixtures and exposure circumstances in the working environment are carcinogenic to humans and are classified as occupational carcinogens (Siemiatycki et al., 2004). That occupational carcinogens are causally related to cancer of the lung, bladder, larynx and skin, leukaemia and nasopharyngeal cancer is well documented. Mesothelioma (cancer of the outer lining of the lung or chest cavity) is to a large extent caused by work-related exposure to asbestos.

Occupational cancers are concentrated among specific groups of the working population, for whom the risk of developing a particular form of cancer may be much higher than for the general population. About 20–30% of the male and 5–20% of the female working-age population (people aged 15–64 years) may have been exposed to lung carcinogens during their working lives, accounting for about 10% of lung cancers worldwide. About 2% of leukaemia cases worldwide are attributable to occupational exposures.

Radiation

Ionizing radiation is carcinogenic to humans. Knowledge on radiation risk has been mainly acquired from epidemiological studies of the Japanese A-bomb survivors as well as from studies of medical and occupational radiation exposure cohorts. Ionizing radiation can induce leukaemia and a number of solid tumours, with higher risks at young age at exposure. Residential exposure to radon gas from soil and building materials is estimated to cause between 3% and 14% of all lung cancers, making it the second cause of lung cancer after tobacco smoke. Radon levels in homes can be reduced by improving the ventilation and sealing floors and walls. Ionizing radiation is an essential diagnostic and therapeutic tool. To guarantee that benefits exceed potential radiation risks radiological medical procedures should be appropriately prescribed and properly performed, to reduce unnecessary radiation doses, particularly in children.

Ultraviolet (UV) radiation, and in particular solar radiation, is carcinogenic to humans, causing all major types of skin cancer, such as basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and melanoma. Globally in 2000, over 200 000 cases of melanoma were diagnosed and there were 65 000 melanoma-associated deaths. Avoiding excessive exposure, use of sunscreen and protective clothing are effective preventive measures. UV-emitting tanning devices are now also classified as carcinogenic to humans based on their association with skin and ocular melanoma cancers.

• Ionizing radiation
• Ultraviolet radiation

Early detection of cancer

Early detection of cancer greatly increases the chances for successful treatment. There are two major components of early detection of cancer: education to promote early diagnosis and screening.

Recognizing possible warning signs of cancer and taking prompt action leads to early diagnosis. Increased awareness of possible warning signs of cancer, among physicians, nurses and other health care providers as well as among the general public, can have a great impact on the disease. Some early signs of cancer include lumps, sores that fail to heal, abnormal bleeding, persistent indigestion, and chronic hoarseness. Early diagnosis is particularly relevant for cancers of the breast, cervix, mouth, larynx, colon and rectum, and skin.

Screening

Screening refers to the use of simple tests across a healthy population in order to identify individuals who have disease, but do not yet have symptoms. Examples include breast cancer screening using mammography and cervical cancer screening using cytology screening methods, including Pap smears. Screening programmes should be undertaken only when their effectiveness has been demonstrated, when resources (personnel, equipment, etc.) are sufficient to cover nearly all of the target group, when facilities exist for confirming diagnoses and for treatment and follow-up of those with abnormal results, and when prevalence of the disease is high enough to justify the effort and costs of screening.

Based on the existing evidence, mass population screening can be advocated only for breast and cervical cancer, using mammography screening and cytology screening, in countries where resources are available for wide coverage of the population. Several ongoings studies are currently evaluating low cost approaches to screening that can be implemented and sustained in low-resource settings. For example visual inspection with acetic acid may prove to be an effective screening method for cervical cancer in the near future. More studies that evaluate low cost alternative methods to mammography screening, such as clinical breast examination, are needed.

More information on screening for cancer

• Screening for various cancers
• Breast cancer: prevention and control
• Screening for cervical cancer
• Screening for colorectal cancer
• Screening for oral cancer

Treatment of cancer

Cancer treatment programmes

The main goals of a cancer diagnosis and treatment programme are to cure or considerably prolong the life of patients and to ensure the best possible quality of life to cancer survivors.

The most effective and efficient treatment programmes are those that: a) are provided in a sustained and equitable way; b) are linked to early detection; and c) adhere to evidence-based standards of care and a multidisciplinary approach.

Such programmes also ensure adequate therapy for cancer types that, although not amenable to early detection, have high potential for being cured (such as metastatic seminoma and acute lymphatic leukaemia in children), or have a good chance of prolonging survival in a significant way (such as breast cancer and advanced lymphomas).

Diagnosis

The first critical step in the management of cancer is to establish the diagnosis based on pathological examination. A range of tests is necessary to determine the spread of the tumour. Staging often requires substantial resources that can be prohibitive in low-resource settings. Because of late diagnosis, however, a consequence of poor access to care, most patients have advanced disease in such settings.

Once the diagnosis and degree of spread of the tumour have been established, to the extent possible, a decision must be made regarding the most effective cancer treatment in the given socioeconomic setting.

Major treatment modalities

This requires a careful selection of one or more of the major treatment modalities – surgery, radiotherapy and systemic therapy – a selection that should be based on evidence of the best existing treatment given the resources available. Surgery alone, and sometimes radiation alone, is only likely to be highly successful when the tumour is localized and small in size. Chemotherapy alone can be effective for a small number of cancers, such as haematological neoplasms (leukaemias and lymphomas), which can generally be considered to be widespread from the outset. Combined modality therapy requires close collaboration among the entire cancer care team.

Palliative care

Palliative care is an essential part of cancer control and can be provided relatively simply and inexpensively.

Palliative care for children represents a special, albeit closely related field to adult palliative care. Palliative care for children is the active total care of the child’s body, mind and spirit, and also involves giving support to the family. It begins when illness is diagnosed, and continues regardless of whether or not a child receives treatment directed at the disease. Health providers must evaluate and alleviate a child’s physical, psychological, and social distress. Effective palliative care requires a broad multidisciplinary approach that includes the family and makes use of available community resources; it can be successfully implemented even if resources are limited. It can be provided in tertiary care facilities, in community health centres and even in children’s homes.

Palliative care improves the quality of life of patients and families who face life-threatening illness, by providing pain and symptom relief, spiritual and psychosocial support to from diagnosis to the end of life and bereavement.

Palliative care

• provides relief from pain and other distressing symptoms;
• affirms life and regards dying as a normal process;
• intends neither to hasten or postpone death;
• integrates the psychological and spiritual aspects of patient care;
• offers a support system to help patients live as actively as possible until death;
• offers a support system to help the family cope during the patients illness and in their own bereavement;
• uses a team approach to address the needs of patients and their families, including bereavement counselling, if indicated;
• will enhance quality of life, and may also positively influence the course of illness;
• is applicable early in the course of illness, in conjunction with other therapies that are intended to prolong life, such as chemotherapy or radiation therapy, and includes those investigations needed to better understand and manage distressing clinical complications.

In most of the world, the majority of cancer patients are in advances stages of cancer when first seen by a medical professional. For them, the only realistic treatment option is pain relief and palliative care. Effective approaches to palliative care are available to improve the quality of life for cancer patients.

The WHO ladder for cancer pain is a relatively inexpensive yet effective method for relieving cancer pain in about 90% of patients.

Global status report on noncommunicable diseases 2010

Description of the global burden of NCDs, their risk factors and determinants

Publication details

Editors: World Health Organization
Number of pages: 176
Publication date: April 2011
Languages: English
ISBN: 978 92 4 156422 9

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