Posted on 5 November, 2011
Cancer screening
or mass screening involves screening everyone.Selective screening identifies people who are known to be at higher risk of developing cancer, such as people with a family history of cancer.
Screening can lead to substantial false positive result and subsequent invasive procedures. Screening for cancer is controversial in cases when it is not yet known if the test actually saves lives. The controversy arises when it is not clear if the benefits of screening outweigh the risks of follow-up diagnostic tests and cancer treatments.
Screening tests suitable for large numbers of apparently healthy people must be relatively affordable, safe, noninvasive procedures with acceptably low rates of false positive results. If signs of cancer are detected, more definitive and invasive follow-up tests are performed to confirm the diagnosis. Screening for cancer can lead to earlier diagnosis in specific cases. Early diagnosis may lead to higher rates of successful treatment and extended life. However, it may also falsely appear to prolong the lead time to death through lead time bias or length time bias.
Cancer screening is not currently possible for some types of cancers, and even when tests are available, they are not recommended to everyone. Cancer screening is not indicated unless individual's life expectancy is greater than five years; the benefit of cancer screening is uncertain over the age of 70.
Principles of screening
Several factors are considered to determine whether the benefits of screening outweigh the risks and the costs of screening. These factors include:
Specific recommendations
Prostate cancer
According to the U.S. Preventive Services Task Force (USPSTF), there is insufficient evidence to recommend for or against screening for prostate cancer in men under 75. Routine screening is not recommended for prostate cancer in men over 75. Most North American medical groups recommend individualized decisions about screening, taking into consideration the risks, benefits, and the patients' personal preferences.
Breast cancer
Cervical cancer
Cervical cancer screening via the Pap smear has the best cost-benefit profile of all the forms of cancer screening from a public health perspective as, being largely caused by a virus, it has clear risk factors (sexual contact), and the natural progression of cervical cancer is that it normally spreads slowly over a number of years therefore giving more time for the screening program to catch it early. Moreover, the test itself is easy to perform and relatively cheap.
The U.S. Preventive Services Task Force (USPSTF) strongly recommends cervical cancer screening in American women who are sexually active and have a cervix at least until the age of 65, usually every three years. Their recommendation is typical of professional organizations and other government agencies in the US and Canada.
Lung Cancer
Recent research suggests that screening heavy smokers may be effective.
Whole body imaging
Use of medical imaging to search for cancer in people without clear symptoms is similarly marred with problems. There is a significant risk of detection of what has been recently called an - a benign lesion that may be interpreted as a malignancy and be subjected to potentially dangerous investigations.
Related Post:
Widget by [ Iptek-4u ]
