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Breast Cancer
What other technologies are under development for breast cancer screening?
The National Cancer Institute (NCI) is supporting the advancement of several new technologies to detect breast tumors. This research ranges from methods under development in research labs to those that have reached the stage of testing in humans (in studies known as clinical trials). Efforts to improve conventional mammography include three technologies: digital mammography, magnetic resonance imaging (MRI), and positron emission tomography (PET scanning). The following two Web sites describe these procedures in more detail.
Digital mammography records x-ray images in computer code instead of on x-ray film, as with conventional mammography. In January 2000, the FDA approved a digital mammography system that may offer potential advantages over the use of standard x-ray film. Research studies so far have not shown that digital images are more effective in finding cancer than x-ray film images. However, NCI is directing additional studies to learn whether digital mammography is as good as or better than conventional mammography. Digital mammography may offer the following advantages over conventional mammography: The images can be stored and retrieved electronically, which makes long-distance consultations with other mammography specialists easier; because images can be adjusted by the radiologist, subtle differences between tissues may be noted; digital mammography may reduce the number of follow-up procedures that are necessary; and the need for fewer exposures with digital mammography can reduce the already low levels of radiation.
Currently, digital mammography can be done only in facilities certified to practice conventional mammography and that have received FDA approval to offer digital mammography. The procedure for having a mammogram with a digital system is the same as with conventional mammography.
In addition to imaging technologies, NCI-supported scientists are exploring methods to detect markers of breast cancer in blood, urine, or nipple aspirates (fluid from the breast) that may serve as early warning signals for breast cancer. The NCI fact sheet Improving Methods for Breast Cancer Detection and Diagnosis provides more information about technologies that are under development for breast cancer screening and diagnosis.
Screening Mammograms, Questions and Answers
Colon Cancer
New tests are currently under investigation for colorectal cancer screening and diagnosis. For example, virtual colonoscopy (also called computed tomographic colonography) is a procedure that uses special x-ray equipment to produce pictures of the colon.
A computer then assembles these pictures into detailed images that can show polyps and other abnormalities. Because it is less invasive and does not require sedation, virtual colonoscopy may cause less discomfort, and may take less time to perform the screening test than conventional colonoscopy. However, unlike conventional colonoscopy, it is not possible to remove polyps or perform a biopsy during virtual colonoscopy. An additional procedure, such as conventional colonoscopy, is needed if the virtual procedure finds a potential problem. Clinical trials, research studies with people are under way to compare the advantages and disadvantages of virtual colonoscopy with those of other colorectal cancer screening tests.
Genetic testing of stool samples is also under study as a possible way to screen for colorectal cancer. The lining of the colon is constantly shedding cells into the stool. The lining of the colon is constantly shedding cells into the stool.
Testing stool samples for genetic alterations that occur in colorectal cancer cells may help doctors find evidence of cancer. Research conducted thus far has shown that this test can detect colorectal cancer in people already diagnosed with this disease by other means. However, more studies are needed to determine whether the test can detect colorectal cancer in people who do not have symptoms.
Additional information about clinical trials to test new methods for colorectal cancer screening is available from the NCI's Web site at http://cancer.gov/clinical_trials/on the Internet, or by calling the CIS at 1-800-4-CANCER (1-800-422-6237).
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