History of Cancer Screening and Early Detection: 20th Century to Present

Screening refers to tests used to find a disease, such as cancer, in people who do not have any symptoms.

The first screening test to be widely used for cancer was the Pap test. The test was developed by George Papanicolaou as a research method in understanding the menstrual cycle. Papanicolaou soon recognized its potential for finding cervical cancer early and presented his findings in 1923. At first, most doctors were skeptical, and it was not until the American Cancer Society (ACS) promoted the test during the early 1960s that this test became widely used. Since that time, cervical cancer incidence and mortality rates have decreased by more than 50% due to screening, which can detect both cervical pre-cancers and cervical cancer at an early stage.

Modern mammography methods were developed late in the 1960s and first officially recommended by the ACS in 1976. The mammogram continues to be the most reliable way to screen for breast cancer.

Current American Cancer Society guidelines include methods for early detection of cervical, breast, colorectal, lung, and prostate cancers.

The future of cancer screening and early detection

Expression profiling and proteomics

Expression profiling lets scientists determine relative output of hundreds or even thousands of molecules (including the proteins made by RNA, DNA, or even a cell or tissue) at one time. Knowing what proteins are present in cells can tell scientists a lot about how the cell is behaving. In cancer, it can help distinguish more aggressive cancers from less aggressive ones, and can often help predict which drugs the tumor is likely to respond to.

Proteomic methods are also being tested for cancer screening. For most types of cancer, measuring the amount of one protein in the blood is not very good at finding early cancers. But researchers are hopeful that comparing the relative amounts of many proteins may be more useful, and that finding large amounts of certain proteins and less of others can provide accurate, useful information about cancer treatment and its outcomes. Proteins (and other types of molecules) are even found in exhaled breath, which is now being tested to find out if it can show early signs of lung cancer. This is an exciting area of research and early results in lung and colorectal cancer studies have been promising.

Nanotechnology

New technology for producing materials that form extremely tiny particles is leading to very promising imaging tests that can more accurately show the location of tumors. It also is aiding the development of new ways to deliver drugs more specifically and effectively to cancer cells.