Cancer causes 580,000 deaths a year in the United States. One in eight women will develop breast cancer and one in six men will be diagnosed with prostate cancer during their lifetimes. However, many deaths can be prevented when cancer is detected at an early stage. Cancer screening and risk assessment tests are the tools we use to find cancers early.
How do we find early cancers?
Some cancer screenings can be done yourself at home at essentially no cost or risk. This includes regular self-examination of the breasts, testicles and skin. Home fecal occult blood testing can also be done to screen for colorectal cancer. Additional information on cancer screening and self-examinations can be found on websites such as www.cancer.org or www.webmd.com.
Other screening requires medical interventions. There is good evidence that well-targeted screening saves lives. However, screening tests such as mammography, colonoscopy and prostate-specific antigen (PSA) are very sensitive and often detect very slow growing cancers or pre-cancerous lesions. It is important to recognize that positive screening tests do not require that all detected lesions need treatment. They require an informed discussion with a physician with expertise in the field.
What are screening guidelines?
The benefits of screening can be maximized and the risk of false positive results minimized, by only screening people who are most likely to develop the cancer that is being screened and benefit from treatment. For example, people whose life expectancy is less than 10 years are not likely to benefit from routine prostate cancer screening because the cancer detected would rarely require treatment during their lifetime.
The American Cancer Society recommends annual screening mammography for healthy women, starting at age 40. Colonoscopy every 10 years is recommended starting at age 50. An annual Pap smear is important for detecting cervical cancer. Screening CT scanning is being investigated for smokers and others at high risk for lung cancer.
What if you are at higher risk?
The need for screening is greater for people at higher risk for cancer. This includes people with a family history of breast, colon, melanoma and prostate cancer. Those with a history of radiation treatment to the chest have increased risk of breast and lung cancer. African-Americans have a higher risk of prostate cancer. People with inflammatory bowel disease have a higher risk of colon cancer, and those with extensive sun exposure are at higher risk for skin cancers.
What about screening tests offered directly to consumers?
Consumers can now purchase an analysis of their own genetic profile that indicates their risk for certain diseases, including some cancers. This is a promising technology which can produce useful information but also inconsistent results and a lot of anxiety. Reports must be interpreted with professional advice. The Swedish Cancer Institute has an excellent medical genetics department that can assist patients.
In recent years there have been other types of cancer screening, such as whole body CT scanning, marketed directly to healthy consumers. There is no evidence that they reduce cancer mortality and they are not recommended by the medical community.
Cancer is common but the most common types are highly curable when detected early. The best step you can take is to determine what cancer screening is most appropriate for your risk profile with a provider.