WHO’s latest cancer report, how to interpret it? Tobacco is the number one risk factor for human cancer and the most important direct risk factor for approximately 20% of all-cause cancer deaths and approximately 70% of lung cancer deaths worldwide. And urban air pollution, which has been the subject of much debate recently, is only listed as the ninth of the top 10 risk factors for all cancers in the current WHO report. The World Health Organization has updated its 2014 World Cancer Report, which provides some additional insights into cancer. Key Facts Cancer is the leading cause of morbidity and mortality worldwide, with approximately 14 million new cancer cases and 8.2 million cancer-related deaths worldwide in 2012. The number of new cases is expected to increase by approximately 70% over the next 20 years. In 2012, the five most common cancers in men were lung, prostate, colorectal, stomach and liver cancers; in women, the five most common cancers were breast, colorectal, lung, cervical and stomach cancers. About one-third of cancer deaths are attributed to the following five major behavioral and dietary risks: body mass index for height, low fruit and vegetable intake, lack of physical activity, smoking, and alcohol consumption. Tobacco use is responsible for about 20% of cancer deaths and about 70% of lung cancer deaths worldwide and is the most important cancer risk factor. Up to 20% of cancer deaths in low- and middle-income countries are attributed to viral infections such as HBV/HCV (hepatitis B and C) and HPV (human papillomavirus) infections that cause cancer. More than 60% of new cancer cases worldwide each year occur in Africa, Asia, Central and South America. These regions account for 70% of global cancer deaths. The annual number of new cancer cases worldwide is expected to rise from 14 million in 2012 to 22 million in the next 20 years. Cancer is a large group of malignant diseases that can affect any part of the body, also called malignant tumors or neoplasms. A distinguishing feature of cancer is that abnormal cells arise rapidly, grow beyond their normal boundaries, and can invade adjacent parts of the body and spread to other organs, the latter by a method known as metastasis. Metastasis is the leading cause of death from cancer. Cancer is the leading cause of death worldwide, causing a total of 8.2 million deaths in 2012. The most common types of cancer that cause cancer deaths: Lung cancer (1.59 million deaths) Liver cancer (7.45 million deaths) Stomach cancer (7.23 million deaths) Colorectal cancer (6.94 million deaths) Breast cancer (5.21 million deaths) Esophageal cancer (4 million deaths) Causes of cancer Cancer develops from a single cell. The transformation from normal cells to tumor cells is a multi-stage process, usually progressing from precancerous lesions to malignant tumors. These changes are the result of a combination of individual genetic factors and three types of exogenous carcinogenic factors: physical carcinogens, such as ultraviolet light and ionizing radiation; chemical carcinogens, such as components of asbestos, tobacco smoke, aflatoxin (a food contaminant) and arsenic (a drinking water contaminant); biological carcinogens, such as certain viral, bacterial or parasitic infections; WHO, through its cancer research agency, the International Agency for Research on Cancer (IARC), has classified carcinogens. Aging is another fundamental factor in the formation of cancer. The incidence of cancer increases significantly with age, mainly because specific cancer risk accumulation increases with age. The overall risk accumulation is the result of a major decrease in the effectiveness of cellular repair mechanisms with age. Risk factors for cancer Tobacco use, alcohol use, unhealthy diet and lack of physical activity are the major cancer risk factors globally. Some risk factors for chronic infections play a role in cancer development in low- and middle-income countries. Hepatitis B virus (HBV), hepatitis C virus (HCV), and some types of human papillomavirus (HPV) infections increase the risk of liver and cervical cancer, respectively. HIV (Human Immunodeficiency Virus) infection greatly increases the risk of developing cancer such as cervical cancer. How can I reduce the burden of cancer? Understanding as much as possible about the causes of cancer and targeting interventions can broadly prevent and control the disease. Cancer can be effectively reduced and controlled by implementing evidence-based cancer prevention, early detection, and cancer patient management strategies. Many types of cancer have a high chance of cure if detected early and treated adequately. How can risk factors be changed and avoided? More than 30% of cancer deaths can be prevented by modifying or avoiding major risk factors, including: tobacco use; overweight or obesity; unhealthy diet, such as low fruit and vegetable intake; lack of physical activity; alcohol consumption; human papillomavirus infection from sexual activity hepatitis B virus infection; ionizing and non-ionizing radiation (ultraviolet light); urban air pollution; household use Indoor smoke from solid fuels. Tobacco use is the most important risk factor for about 20% of global cancer deaths and about 70% of global lung cancer deaths. In many low-income countries, up to 20% of cancer deaths are due to hepatitis B virus and human papillomavirus infections. Cancer prevention strategies Avoidance of the risk factors listed above where possible; Vaccination against human papillomavirus (HPV) and hepatitis B virus (HBV); Control of occupational hazards; Reduction of exposure to non-ionizing radiation from sunlight (UV light); Reduction of exposure to ionizing radiation (occupational or medical diagnostic imaging). Early detection of cancer Early detection and early treatment can be effective in reducing cancer mortality. Early detection includes the following 2 components: Early diagnosis – being alert to early signs and symptoms of cancer (e.g. skin, cervical, breast, colon, rectal and oral cancer) for early diagnosis and early treatment. Early diagnosis is especially important in cases where lack of effective screening methods or low resource allocation results in failure to implement screening and treatment interventions. Without any early detection, screening and therapeutic interventions, radical treatment is no longer an option for patients diagnosed at very late stages. Screening – The purpose of screening is to detect abnormal signs of specific cancers or precancerous lesions through procedural testing, which can then be referred for further testing or treatment, and is an effective strategy for early cancer diagnosis. Screening programs are particularly effective for common cancer types and include cost-effective, affordable, easily accepted and available screening test methods that can effectively reduce mortality in these cancer-risk populations. Common screening programs include: visual inspection with acetic acid (VIA) screening for cervical cancer in low-resource allocation areas; HPV testing for cervical cancer; PAP cytology testing for cervical cancer in medium- and high-resource allocation; and mammography screening for breast cancer in high-resource allocation. Cancer Treatment A clear cancer diagnosis is essential for adequate and effective treatment, as treatment options for each cancer type include one or more specific treatment modalities, such as surgery, radiation therapy, and chemotherapy. The primary goal of cancer treatment is to cure or significantly extend life expectancy. Improving the patient’s quality of life is also an important treatment goal, and this can be achieved through supportive or end-of-life care as well as psychological support. Early detection or cure of the underlying cancer. Some of the most common types of cancer have high cure rates when detected and treated early according to best practice guidelines, such as breast, cervical, oral and colorectal cancers. Early detection or cure of certain cancers. Certain types of cancer, even if they have metastasized, have a high cure rate if appropriate treatment is provided, such as childhood-onset leukemia and lymphoma, and testicular seminoma. End-of-life care Hospice care is treatment for the relief of symptoms caused by cancer and is not intended to be a cure. Hospice care can help people live more comfortably; it is a worldwide humanitarian need for people with cancer and other fatal chronic diseases, especially for those with advanced disease who have lost their chance of a cure. Physical, psychological and spiritual problems can be alleviated in more than 90 percent of patients with advanced cancer through hospice care. End-of-life care strategies Pain relief and hospice care are effective and essential public health strategies for low-income, including community and home-based primary care patients and families. For the moderate to severe cancer pain experienced by more than 80% of patients with end-stage cancer, relaxation of control of oral morphine therapy is essential.