cause of cancer death among U.S. men and women.
There are various racial and ethnic differences in inci-
dence of cancer and deaths from cancer in the United
States. Some of these differences may be due to cul-
tural factors such as behaviors or access to care.
Others may be related to genetics. Survival rates for
all races and types of cancer combined continue to
increase substantially. From 1996-2002, 66% of can-
cer survivors lived five years or longer, combined with
only 50% between 1975 and 1977.Causes and symptomsThere are numerous risk factors and causes of
cancer. Among them are age, sex, and family medical
history. Some risk factors depend on the type of can-
cer. In some cases, a person may have more than one
risk factor for the disease. Another person may be
diagnosed with cancer and have no apparent risk fac-
tor. Genetic causes can’t be controlled by an individ-
ual, but people who know they are at risk because a
close relative had a particular cancer should follow all
recommendations for screening and prevention.
Often, physicians cannot explain what causes can-
cer. In addition to a family history of cancer, overall
risk factors for cancer include aging, tobacco or alco-
hol use, exposure to sunlight or ionizing radiation,
exposure to certain chemicals or substances, and expo-
sure to some viruses and bacteria. Poor diet, lack of
physical activity, or being overweight also are risk
factors for cancers. Not all of these risk factors pertain
to all cancers. For example, exposure to sunlight is a
risk factor for skin cancer, while certain hormones
increase the risk of breast cancer.
Cancer may not produce pain. And many symp-
toms may be due to a condition that is not cancer. But
any signs similar to those for a particular cancer or
that show a change in health should be checked by a
physician. Symptoms vary depending on the type ofcancer, but some common symptoms of cancer
include:
feeling weak or very tired
a lump in the breast or any other part of the body
a new mole or changes in an existing mole
changes to bowel or bladder habits
hoarseness or a cough that won’t go away
a sore that doesn’t heal
difficulty swallowing
unexplained weight loss or weight gain
unusual discharge or bleedingDiagnosisGenerally, the earlier cancer is found, the better.
Many cancer types have screening methods to help find
them early. For example, screening mammography
helps detect breast cancer before symptoms occur. A
Pap test screens for cervical cancer. Several tests, such
as colonoscopy, are recommended for people of certain
ages or with certain risk factors, to screen for colon and
rectal cancer. It is important to follow the guidelines of
organizations such as the American Cancer Society
concerning recommended screening for cancers.
Physicians use a combination of family and med-
ical history, screening examination results, laboratory
examinations, imaging examinations, and other pro-
cedures to diagnose cancer. Family and medical his-
tory are important to look for hereditary links to many
cancers. Medical history helps to determine if a person
may have behaviors, such as smoking, that increase
risk for many cancers.
Laboratory examinations may test a person’s
blood, urine, or other fluids. These tests often are con-
ducted to search for levels of substances called tumor
markers. Laboratory tests alone cannot diagnose can-
cer, but can help lead a physician toward or away from
a suspected diagnosis.KEY TERMS
Benign—Mild, does not threaten health or life.
When referring to a tumor, it generally means
noncancerous.
Malignant—Unfavorable, tending to produce dete-
rioration or death. For a tumor, it generally means
cancerous.
Radiopharmaceutical—A drug that is radioactive.
It is used for diagnosing or treating diseases.Most prevalent cancer-related deaths, 2002Male cancers Deaths (000) Female cancers Deaths (000)
Trachea/ 886 Breast 474
bronchus/lung Trachea/
Stomach 523 bronchus/lung 353
Liver 428 Stomach 326
Colon/rectum 321 Colon/rectum 299
Oesophagus 284 Cervix Uteri 239
Prostate 268 Liver 191
SOURCE: The World Health Report 2003(Illustration by GGS Information Services/Thomson Gale.)Cancer