Global Risk Factors For Cancer

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• Global Risk Factors For Cancer
• By
• Salwa Hassan Teama
• M.D.N.C.I. Cairo, Egypt

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Contents

• Cancer
• Cancer as a Global Health Problem
• Cancer As a Genetic Disease
• Risk Factor
• Global Risk Factor Of Cancer
• Avoidable Cancer Risk
• Primary Prevention
• Early detection (Screening)
• Genetic testing

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Cancer

• Cancer is one of the most common and severe
  problems of clinical medicine.
• Cancer is not a single disease but rather a name
  applied to a great variety of malignant tumor
  that are formed by the same basic process of
  uncontrolled growth.

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Cancer as a Global Health Problem

• Cancer has emerged as a major public health
  problem in developing countries for the first
  time, matching its effect in industrialized
  nations. This is a global problem.

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Cancer

• Cancer begins in cells, the building blocks that
  form tissues.
• Normally, cells grow and divide to form new cells
  as the body needs them. When cells grow old, they
  die, and new cells take their place.
• Sometimes, this orderly process goes wrong. New
  cells form when the body does not need them, and
  old cells do not die. These extra cells can form
  a mass of tissue called a growth or tumor.

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Cancer

• Cell proliferation results in a mass (neoplasm or
  tumor) that invade neighboring tissues and may
  metastasize to more distant sites. The growth is
  autonomous, increasingly malignant, and if left
  untreated, invariably fatal.
• Early diagnosis and early treatment are vital,
  and identification of persons at increased risk
  of cancer before its development is an important
  objective of cancer research.

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Cancer

• The etiology of cancer is multifactorial, with
  genetic, environmental, medical, and lifestyle
  factors interacting to produce a given
  malignancy.
• Knowledge of cancer genetics is rapidly improving
  our understanding of cancer biology, helping to
  identify at-risk individuals, this expanding
  knowledge base has implications for all aspects
  of cancer management, including prevention,
  screening, and treatment.

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Cancer As a Genetic Disease

• It is now believed that cancer is caused by
  genetic mutations most often, by a series of
  mutations, some of which may be inherited.
• Certain normal genes involved in cell growth,
  development, and differentiation can be converted
  into cancer-causing "oncogenes" by mutation.
  Other genes that normally prevent the
  uncontrolled growth of cells "suppressor" genes
  can also produce cancer if they are knocked out
  by genetic mutations.

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Cancer As a Genetic Disease

• Single mutations are generally not sufficient to
  cause cancer, but they produce changes that may
  predispose cells to malignant growth. Additional
  mutations in other genes, caused by damage from
  the environment, continue the cells' malignant
  transformation. Thus, cancer is a multi-step
  process involving the interaction between genes
  and their environment.

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www.accessexcellence.org/.../genes-cancer.gif
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Cancer as a Global Health Problem

• In the year 2000, malignant tumors were
  responsible for 12 percent of the nearly 56
  million deaths worldwide from all causes. In many
  countries, more than a quarter of deaths are
  attributable to cancer. In 2000, 5.3 million men
  and 4.7 million women developed a malignant tumor
  and altogether 6.2 million died from the disease.
  

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Cancer as a Global Health Problem

• The predicted sharp increase in new cases from 10
  million new cases globally in 2000, to 15 million
  in 2020 will mainly be due to steadily ageing
  populations in both developed and developing
  countries and also to current trends in smoking
  prevalence and the growing adoption of unhealthy
  lifestyles.

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Risk Factor

• A risk factor is anything that increases a
  person's chance of getting a disease. Some risk
  factors can be changed, and others cannot. Risk
  factors for cancer can include a person's age,
  sex, and family medical history. Others are
  linked to cancer-causing factors in the
  environment. Still others are related to
  lifestyle choices such as tobacco and alcohol
  use, diet, and sun exposure.

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Risk Factor

• Cancers of the lung, mouth, larynx, bladder,
  kidney, cervix, esophagus, and pancreas are
  related to tobacco use, including cigarettes,
  cigars, chewing tobacco, and snuff. Smoking alone
  causes one-third of all cancer deaths.
• Skin cancer is related to unprotected exposure to
  strong sunlight.

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Risk Factor

• Breast cancer risk factors include several
  factors age changes in hormone levels
  throughout life, such as age at first
  menstruation, number of pregnancies, and age at
  menopause obesity and physical activity. Also,
  women with a mother or sister who have had breast
  cancer are more likely to develop the disease.

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Risk Factor

• Prostate cancer risk factors include
• Age, race, and diet
• Older age
• Prostate cancer is more common among
  African-American men than among white men.
• High-fat diet
• Men with a father or brother who have had
  prostate cancer are more likely to get it.

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Global Risk Factor Of Cancer

• Old age
• Environmental factors, defined broadly to include
  tobacco use, diet, infectious diseases and
  sunlight.
• Unhealthy lifestyle (Western lifestyle) Poor
  diet, lack of physical activity, or being
  overweight
• Occupational carcinogens
• Radiation
• Chemicals and other substance
• Obesity
• Family history of cancer (Genetic susceptibility)
• Alcohol
• In the gastro-intestinal tract (GIT), any chronic
  tissue damage with necrosis and regeneration
  carries an in creased cancer risk, e.g.
  consumption of very hot beverages (squamous cell
  carcinoma of the esophagus), gastro-oesophageal
  reflux (adenocarcinoma of the esophagus), chronic
  gastritis induced by H. pylori infection (stomach
  cancer), Crohns disease (cancer of the small
  intestines) and ulcerative colitis (colon cancer)

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Global Risk Factor Of Cancer

• Many of these risk factors can be avoided.
  Others, such as family history, cannot be
  avoided. People can protect themselves by staying
  away from known risk factors whenever possible.

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Global Risk Factor Of Cancer

• Growing Older
• The most important risk factor for cancer is
  growing older. Most cancers occur in people over
  the age of 65. But people of all ages, including
  children, can get cancer, too ...

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Global Risk Factor Of Cancer

• Tobacco
• Tobacco use is the most preventable cause of
  death.
• Using tobacco products or regularly being around
  tobacco smoke (environmental or secondhand smoke)
  increases the risk of cancer.
• Smokers are more likely than nonsmokers to
  develop cancer.
• People who use smokeless tobacco (snuff or
  chewing tobacco) are at increased risk of cancer
  of the mouth.

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Global Risk Factor Of Cancer

• Sunlight
• Ultraviolet (UV) radiation comes from the sun,
  sunlamps, and tanning booths. It causes early
  aging of the skin and skin damage that can lead
  to skin cancer.

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Global Risk Factor Of Cancer

• Poor Diet, Lack of Physical Activity, or Being
  Overweight People may be at increased risk of
  several types of cancer. For example, studies
  suggest that people whose diet is high in fat
  have an increased risk of cancers of the colon,
  uterus, and prostate. Lack of physical activity
  and being overweight are risk factors for cancers
  of the breast, colon, esophagus, kidney, and
  uterus. Choose a diet rich in fruits and
  vegetables.

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Global Risk Factor Of Cancer

• Being infected with certain viruses or
  bacteria may increase the risk of developing
  cancer
• Human papillomaviruses HPV infection is the
  main cause of cervical cancer. It also may be a
  risk factor for other types of cancer.
• Hepatitis B and hepatitis C viruses Liver cancer
  can develop after many years of infection with
  hepatitis B or hepatitis C.
• Human T-cell leukemia/lymphoma virus HTLV-1
  Infection with HTLV-1 increases a person's risk
  of lymphoma and leukemia.
• Human immunodeficiency virus HIV HIV is the
  virus that causes AIDS. People who have HIV
  infection are at greater risk of cancer, such as
  lymphoma and a rare cancer called Kaposi's
  sarcoma.
• Epstein-Barr virus EBV Infection with EBV has
  been linked to an increased risk of lymphoma.
• Human herpesvirus 8 HHV8 This virus is a risk
  factor for Kaposi's sarcoma.
• Helicobacter pylori This bacterium can cause
  stomach ulcers. It also can cause stomach cancer
  and lymphoma in the stomach lining.

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Global Risk Factor Of Cancer

• The Western lifestyle and its health risksThe
  Western lifestyle is characterized by a highly
  caloric diet, rich in fat, refined carbohydrates
  and animal protein, combined with low physical
  activity, resulting in an overall energy
  imbalance. It is associated with a multitude of
  disease conditions, including obesity, diabetes,
  cardiovascular disease, arterial hypertension and
  cancer.

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Global Risk Factor Of Cancer

• Ionizing Radiation
• Ionizing radiation can cause cell damage that
  leads to cancer.
• Certain Chemicals and Other Substances
• People who have certain jobs (such as painters,
  construction workers, and those in the chemical
  industry) have an increased risk of cancer. Many
  studies have shown that exposure to asbestos,
  benzene, benzidine, cadmium, nickel, or vinyl
  chloride in the workplace can cause cancer.

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Global Risk Factor Of Cancer

• Certain Hormones
• Recommendation of hormones estrogen alone or
  estrogen along with progestin to help control
  problems (such as hot flashes, vaginal dryness,
  and thinning bones) that may occur during
  menopause. However, studies show that menopausal
  hormone therapy can cause serious side effects .
  Hormones may increase the risk of breast cancer,
  heart attack, stroke, or blood clots.

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Global Risk Factor Of Cancer

• Obesity is spreading epidemically throughout
  the world. It visualizes a chronic energy
  imbalance and is an independent predictor of an
  increased cancer risk, particularly for
  carcinomas of the uterine endometrium, kidney and
  gall bladder.

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Global Risk Factor Of Cancer

• Family History of Cancer
• Most cancers develop because of changes
  mutations in genes. A normal cell may become a
  cancer cell after a series of gene changes occur.
  
• Some gene changes that increase the risk of
  cancer are passed from parent to child. These
  changes are present at birth in all cells of the
  body.

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Global Risk Factor Of Cancer

• Alcohol
• Having more than two drinks each day for many
  years may increase the chance of developing
  cancers of the mouth, throat, esophagus, larynx,
  liver, and breast. The risk increases with the
  amount of alcohol that a person drinks. The risk
  is higher for a drinker who uses tobacco.

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Cancer control strategies

• The aim of cancer control is a reduction in
  both the incidence of the disease and the
  associated morbidity and mortality, as well as
  improved life for cancer patients and their
  families. In addition to substantial
  opportunities for primary prevention.

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Primary Prevention
Avoidable Cancer Risk

• The best possible prevention against cancer
  remains the avoidance of exposure to
  cancer-causing agents this is called primary
  prevention (e.g tobacco, industrial carcinogens,
  etc .
• Reduction of tobacco consumption. It remains the
  most important avoidable cancer risk. In the 20th
  century, approximately 100 million people died
  world-wide from tobacco-associated diseases .

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Avoidable Cancer Risk

• Having a healthy diet, being physically active,
  and maintaining a healthy weight may help reduce
  cancer risk.
• Eat well A healthy diet includes plenty of
  foods that are high in fiber, vitamins, and
  minerals. This includes whole-grain breads and
  cereals and 5 to 9 servings of fruits and
  vegetables every day. Also, a healthy diet means
  limiting foods high in fat (such as butter, whole
  milk, fried foods, and red meat .
• Be active and maintain a healthy weight Physical
  activity can help control your weight and reduce
  body fat. Moderate physical activity (such as
  brisk walking) for at least 30 minutes on 5 or
  more days each week is recommended.

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Food Guide Pyramid
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Avoidable Cancer RiskEarly DAETECTION (Screening)

• Early detection the best strategy second to
  primary prevention.
• Early detection through screening, particularly
  for cervical and breast cancers, allow for
  prevention and successful cure.

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Screening and 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.

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Screening and early detection of cancer

• Recognizing possible warning signs of cancer
  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.

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• The most successful is the early detection of
  cervical cancer by cytology and of breast cancer
  by mammography.
• Prostate cancer screening by assessment of
  serum PSA levels may result in lower mortality
  rates.
• For colon cancer, colonoscopy is considered the
  gold standard although its application in
  population-based screening programs would require
  considerable medical resources.

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Avoidable Cancer Risk

• Vaccinations HBV vaccination has already been
  shown to prevent liver cancer in high-incidence
  countries and it is likely that human
  papillomavirus (HPV) vaccination will become a
  reality in 3 to 5 years.

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Avoidable Cancer Risk

• Genetic testing. These tests can check for
  certain inherited gene changes that increase the
  chance of developing cancer. But inheriting a
  gene change does not mean that you will
  definitely develop cancer. It means that you have
  an increased chance of developing the disease.

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Avoidable Cancer Risk

• Genetic information Sources of genetic
  information include biologic samples of DNA,
  information derived from a persons with a family
  history of disease.
• Family history may identify people with a modest
  to moderately increased risk of cancer or may
  serve as the first step in the identification of
  an inherited cancer predisposition that confers a
  very high lifetime risk of cancer. For an
  increasing number of diseases, DNA-based testing
  can be used to identify a specific mutation as
  the cause of inherited risk and to determine
  whether family members have inherited the
  disease-related mutation.

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Avoidable Cancer Risk

• Genetic testing Drawback
• Psychological impact. First, there are the
  emotions aroused by learning that one is or is
  not likely to develop a serious disease. Many
  people in disease families have already seen
  close relatives fall victim to the disorder. So
  persons carry the disease gene can elicit
  depression, even despair.

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Avoidable Cancer Risk

• School education programs for tobacco hazards
  and healthy dietary habits, especially because
  very few countries currently have effective
  education programs.
• National cancer control programs can help to
  ensure that governments take the necessary
  actions to guarantee that the public has the
  motivation to adopt healthy personal habits.

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Avoidable Cancer Risk

• New drugs will not necessarily eradicate tumors,
  but when used in combination with other agents,
  may turn many cases of rapidly fatal cancer into
  manageable chronic illness.

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conclusion

• Primary prevention by avoidance of risk factor ,
  Education to promote early diagnosis and
  screening are the gold standard to decrease
  cancer risk and benefit of all humankind.

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References Further Reading

• http//www.who.int/topics/cancer/en/
• http//www.cancer.org/docroot/CRI/content
• http//www.cancer.gov/cancertopics/wyntk/overview/
  page4
• http//www.accessexcellence.org/AE/AEPC/NIH/gene13
  .html
• http//www.nci.nih.gov/cancertopics/pdq/genetics/o
  verview/healthprofessional