Cancer is a group
of diseases characterized by the uncontrolled growth and spread
of abnormal cells. If the spread is not controlled, it can
result in death.
It is believed that cancer is caused by external factors (tobacco,
chemicals, radiation or infectious organisms) and internal factors
(inherited mutations, hormones, immune conditions and mutations
that occur from metabolism). These causal factors may act together
or in sequence to initiate or promote carcinogenesis. Ten or
more years often pass between exposures or mutations and detectable
cancer. Cancer is treated by surgery, radiation, chemotherapy,
hormones, and immunotherapy. (text excerpted from ACS Cancer Facts and Figures 2008)
The most important risk factor is cigarette smoking; other
risk factors are occupational exposure to benzidine and 2-naphthylamine
and occupations in the dye, leather or rubber industry. Possible
risk factors are heavy coffee consumption, bladder infection with
schistosoma haematobium (a parasitic flatworm), treatment with
chlornaphazine or cyclophosphamide (anti-cancer drugs), long-term
use of pain killers containing phenacetin, urinary tract infections
or low urine flow, dietary factors, tobacco use other than cigarettes,
and genetic factors.
Brain Risk factors are genetic factors, certain rare inherited syndromes such as neurofibromatosis, being a parent or sibling of a child with brain cancer, high doses of ionizing radiation, and occupational exposure to certain aromatic hydrocarbon compounds, bis-chloromethyl ether, vinyl chloride, and acrylonitrile. Possible risk factors are exposure to electromagnetic fields, exposure to farm animals and pets, severe head trauma, loud noise, and N-nitroso compounds in the diet, cigarettes, and alcohol.
Breast For women, risk factors are family history (especially mother or sister) of breast cancer, personal history of breast, ovarian, or endometrial cancer, susceptibility genes (BRCA-1, BRCA-2), some forms of benign breast disease (atypical hyperplasia), higher education and socioeconomic status, menstruation at an early age, late menopause, never bearing children, first child born after age 30, high doses of ionizing radiation, long term use of post-menopause estrogens and progestins, obesity after menopause, and excessive alcohol consumption. Possible risk factors are dietary fat and physical inactivity. For men, risk factors include increasing age, family history, radiation exposure, and having high levels of estrogen due to inherited gene mutations or treatments. Possible risk factors include gynecomastia and obesity.
Risk factors are infection with human papilloma viruses (HPV),
early age at first sexual intercourse, many sexual partners or partners
who have had many sexual partners, multiple births, long-term oral
contraceptive use, and cigarette smoking. Possible risk factors are
certain vitamin deficiencies and hormonal factors.
Risk factors are personal or family history of colorectal polyps or inflammatory bowel disease, certain rare hereditary conditions, and a diet high in fat and/or low in fiber, fruits and vegetables. Possible risk factors are physical inactivity, alcohol consumption, obesity, and smoking. Risk may be reduced by estrogen replacement therapy, non-steriodal anti-inflammatory drugs (e.g. aspirin, ibuprofen), dietary
calcium and vitamin D.
High cumulative exposure to estrogens including never bearing children or bearing few children, menstruation beginning at an early age, failure to menstruate, late menopause, estrogen replacement therapy are major risk factors. Also, use of tamoxifen, infertility, obesity, diabetes, hypertension, gallbladder disease, and Stein-Leventhal syndrome are known risk factors. Possible risk factors are dietary fat and hereditary non-polyposis colon cancer.
The most important risk factors are tobacco use (cigarettes,
cigars, pipes), and excessive alcohol use along with the syndrome,
Barrett's esophagus. Possible risk factors are obesity, inadequate
diet, poor nutrition, decreased levels of certain nutrients (carotene,
ascorbic acid, riboflavin, niacin, thiamin, zinc, magnesium, and selenium),
and insufficient consumption of fruits and vegetables.
The most important risk factor is gallstones; factors
related to stone formation are increasing age, being female, being
pregnant, certain ethnicity, obesity, use of estrogen-containing
drugs and high fat and caloric intake.
Cigarette smoking is the most important risk factor; others
are obesity, abuse of analgesics (especially phenacetin-containing
pain relievers), and occupational exposure to arsenic. Possible risk
factors are regular use of prescription diuretics and increased meat
Most cases are caused by cigarette smoking. Other risk factors
are alcohol and occupational exposure to asbestos or mustard gas.
Risk factors are family history, high doses of ionizing
radiation, alkylating drugs used to treat cancer and other diseases,
human T-cell leukemia/ lymphoma virus I infection, Down syndrome
or other genetic abnormalities, and occupational exposure to benzene.
Possible risk factors are exposure to electromagnetic fields, pesticides,
smoking, and several immune-related diseases.
Risk factors are chronic infection with hepatitis B or C virus,
cirrhosis of the liver (chronic liver injury, usually due to alcohol
abuse ), aflatoxin ingestion (produced by a common mold that invades
poorly stored peanuts and other foods), and occupational exposure to
thorium dioxide or vinyl chloride. Possible risk factors are use of
steroids, smoking, and some inherited metabolic diseases (e.g. hemochromatosis).
Tobacco smoking is responsible for nearly 90% of all lung cancers.
Other contributing risk factors are smoking cigars or pipes and
environmental tobacco smoke (second-hand smoke). High doses of
ionizing radiation, residential radon exposure and occupational
exposure to mustard gas, chloromethyl ethers, inorganic arsenic,
chromium, nickel, vinyl chloride, radon, asbestos or byproducts
of fossil fuel are also thought to increase risk. Possible risk
factors are air pollution and insufficient consumption of fruits
Risk factors are infectious mononucleosis and Epstein-Barr
virus infection. Possible risk factors are family history of Hodgkin
lymphoma especially among siblings and genetic factors.
Risk factors are reduced immune function due
to organ transplants or nfection with HIV, Epstein-Barr or human
T-cell leukemia/lymphoma virus. Possible risk factors are occupational
exposure to pesticides, herbicides, or organic solvents.
Tobacco and alcohol usage accounts for most mouth cancers. Another
risk factor is a diet low in fruits and vegetables and possible risk
factors are poor tooth development and oral hygiene, trauma due to
ill-fitting dentures or jagged teeth, use of mouthwashes with high
alcohol content, and iron-deficiency anemia.
High doses of ionizing radiation is a risk factor.
Possible risk factors are repeated infections, allergic conditions,
autoimmune disease, genetic factors, cigarette smoking, farming,
and occupational exposure to benzene.
Risk factors are personal history of breast cancer, family
history of breast or ovarian cancer, susceptibility genes (BRCA-1,
BRCA-2), never bearing children, and hereditary non-polyposis colon
cancer. A possible risk factor is dietary fat. Risk may be reduced
by tubal ligation and hysterectomy.
Risk factors are cigarette smoking and possibly alcohol, coffee,
or tea consumption, diabetes, chronic pancreatitis, cirrhosis, allergies,
diet high in meat or butter fat.
Risk factors are some types of prostatic hyperplasia and
a family history, especially a father or brother. Possible risk
factors are a diet high in animal fat, obesity, hormonal factors,
a sexually transmitted agent, smoking, alcohol, and physical inactivity.
Black males have much higher prostate cancer rates than white males.
Skin cancer, melanoma
Risk factors are excessive exposure to ultraviolet radiation
(sunlight), fair skin, history of severe sunburns, personal or
family history of melanoma, multiple moles or atypical moles (colored
skin spots), giant congenital moles, xeroderma pigmentosum (a rare
hereditary disease), personal history of melanoma, and reduced
immune function due to organ transplants or HIV infection. Melanoma
occurs almost exclusively among whites.
Skin cancer, Non-melanoma
Risk factors are ultraviolet radiation (sunlight),
fair skin, high doses of ionizing radiation, occupational exposure
to arsenic, polycyclic hydrocarbons (coal tars, pitches, asphalt,
creosote, soot, lubricating and cutting oils) and rare hereditary
diseases such as multiple basal cell carcinoma syndrome, xeroderma
pigmentosum, and albinism. Possible risk factors are burn scars,
chronic infections, and photosensitizers in tanning aids, cosmetics,
Risk factors are dietary nitrites (in pickled, salted, and
smoked foods), pernicious anemia, and diet low in fruits and vegetables.
Possible risk factors are infection with Helicobacter pylori, high
doses of ionizing radiation, cigarette smoking, and genetic factors.
Risk factors are high doses of ionizing radiation and goiter.
1 American Cancer Society. Cancer Facts & Figures, 2002.
2 Harras A, editor. Cancer Rates and Risks, USDHHS, NIH 1996.