Cancer starts from the uncontrolled division of cells in the body. As the abnormal cells continue to grow, they form a tumor. As the tumor grows it can metastasize, or spread, and begin forming new tumors in different parts of the body. Not all cancers behave the same way; different types of cancer have different growth rates and respond differently to anti-cancer treatments. In medical terms, cancer is referred to as malignant neoplasms.
Approximately 1.4 million Americans are expected to be diagnosed with cancer during 2007. The National Cancer Institute (NCI) estimated that in January 2003, there were approximately 10.3 million living Americans with a history of cancer. The risk of being diagnosed with cancer increases as a person ages, and 77% of all cancers are diagnosed in Americans age 55 years or older. Cancer, a diverse group of diseases characterized by the uncontrolled growth and spread of abnormal cells, is believed to be caused by both external and internal risk factors.
Major risk factors for cancer include tobacco use, diet, exercise, and sun exposure (Clapp, Howe, Jacobs)1. For example, male smokers are about 23 times more likely to develop lung cancer than male non-smokers. Researchers have also identified genetic risks for cancer. Female first degree relatives (mother, sisters, and daughters) of women with breast cancer are about twice as likely to develop breast cancer as women who do not have a family history of breast cancer (Cancer Facts and Figures, 2007; ACS, 2007)2.
Nobody is immune from getting cancer. Even though scientific studies have shown that specific factors increase the risk for cancer, sometimes people who have no risk factors still develop cancer and people who have many risk factors do not develop cancer. The following list contains common cancer risk factors. It is important to remember that some of these are modifiable and some are not:
- Older age; the risk of developing cancer increases with age
- Race and ethnicity; people of certain races and ethnic background are at higher risk for certain types of cancer
- Tobacco use
- Certain environmental exposures
- Genetics and family history
- Certain medical conditions/diseases such as a weak immune system, diabetes, Crohn's disease, or human papillomavirus (HPV) infection
There are many ways to reduce your risk for cancer. Following these guidelines will not only reduce your risk for cancer, but improve your general health as well:
- Maintain a healthy weight
- Exercise regularly
- Do not smoke; if you already smoke, look for ways to quit
- If you drink alcohol, drink only in moderation
- Receive proper immunizations; certain infectious diseases like the human papillomavirus (HPV) and Hepatitis B and C could lead to cancer later in life
- Protect your skin from the sun; wear proper sun-protection clothing and use plenty of sunscreen when you are outside
- Limit your exposure to environmental risk factors, such as asbestos, radon, arsenic, and benzene
- Get regular medical check-ups, including cancer screening tests like mammography, Pap test, and colonoscopy. Early detection of cancer significantly improves the chances of a complete recovery.
Cancer data come from several sources:
- Screening: The Behavioral Risk Factor Surveillance System (BRFSS) monitors the use of preventive screening for a variety of cancer types such as mammography to detect breast cancer, Pap tests for cervical cancer, colonoscopy for colorectal cancer, and PSA tests for prostate cancer.
- Incidence, stage at diagnosis, and survivorship: State cancer registries collect detailed information about cancer patients and the treatments they receive, which makes the monitoring of trends in incidence and mortality as well as the evaluation of prevention and control measures possible.
- Mortality: Death certificates are a fundamental source of demographic, geographic, and cause-of-death information. They make it possible to track every death in the nation due to cancer. Deaths are reported as being due to cancer when the cancer was the underlying cause of death.