Screening

 Cancer screening is an attempt to detect unsuspected cancers. Screening tests must be relatively affordable, safe for patients, noninvasive procedures with low rates of false positive results. If signs of cancer are detected, more definitive and invasive tests are performed to confirm the diagnosis.

 Screening for cancer can lead to earlier diagnosis. Early diagnosis may lead to extended life. A number of different screening tests have been developed. Breast cancer screening can be done by breast self-examination. Screening by regular mammograms detects tumors even earlier than self-examination, and many countries use it to systematically diagnose all middle-aged women.

Colorectal cancer can be detected through fecal blood testing and colonoscopy, which reduces both colon cancer incidence and mortality. The test leads presumably to the detection and removal of pre-cancerous polyps.

Similarly, cervix’s testing (using the Pap smear) leads to the identification and excision of precancerous lesions. Over time, this testing has been followed by a dramatic reduction of cervical cancer incidence and mortality.

Testicular self-examination is recommended for men beginning at the age of 15 years to detect testicular cancer. Prostate cancer can be identified with a digital rectal exam along with prostate specific antigen- blood testing.

 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. In case of a breast cancer, there have recently been criticisms that breast screening programs in some countries cause more problems than they solve. This is because screening of women will result in a large number of women with false positive results which require extensive investigations to exclude cancer, which will lead to a high number of women that need treatment.

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. Having cervical cancer 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.

 For these reasons, it is important that the benefits and risks of diagnostic procedures and treatment be taken into account when considering whether to undertake cancer screening test.