Techniques for Detecting Breast Cancer
Clinical Breast Exam
A breast exam by a doctor or nurse can find some cancers missed by mammography, even very small ones. In addition to the skill and carefulness of the examiner, the success of a physical exam can be influenced by your monthly cycle and by the size of your breast, as well as by the size and location of the lump itself. Lumps are harder to find in a large breast.
What should I expect?
The examiner will look at your breasts while you are sitting and while you are lying down. You may be asked to raise your arms over your head or let them hang by your sides, or to press your hands against your hips.
The examiner checks your breasts carefully for changes in the skin such as dimpling, scaling, or puckering; any discharge from the nipples; or any difference in appearance between the two breasts, including differences in size or shape.
The next step is palpation: Using the pads of the fingers to feel for lumps, the examiner will systematically inspect the entire breast, the underarm, and the collarbone area, first on one side, then on the other.
A lump is generally the size of a pea before a skilled examiner can detect it. Lumps that are soft, round, and smooth tend not to be cancerous. An irregular, hard lump that feels firmly anchored within the breast tissue is more likely to be a cancer. However, these are general observations, not hard and fast rules.
~ The only sure way to know if a solid lump is cancer is to have some tissue removed and examined under the microscope. ~
Other Tests
Ultrasound
Ultrasound works by sending high-frequency sound waves into the breast. The pattern of echoes from these sound waves is converted into an image (sonogram) of the breast's interior.
Ultrasound, which is painless and harmless, can distinguish between tumors that are solid and cysts, which are filled with fluid. Sonograms of the breast can also help radiologists to evaluate some lumps that can be felt but are hard to see on a mammogram, especially in the dense breasts of young women.
Unlike mammography, ultrasound cannot detect the microcalcifications that sometimes indicate cancer, nor does it pick up small tumors.
CT Scanning
Computed tomography, or CT scanning, uses a computer to organize and stack the information from multiple X-ray, cross-sectional views of a body's organ or area.
The scans are made by having the source of an X-ray beam rotate around the patient. X-rays passing through the body are detected by sensors that pass the information to computers.
Once processed, the information is displayed as an image on a video screen. CT can separate overlapping structures precisely and is sometimes helpful in locating breast abnormalities that are difficult to pinpoint with mammography or ultrasound--for instance, a tumor that is so close to the chest wall that it shows up in only one mammographic view.
Research on New Techniques
Several new techniques for imaging the breast are in the research stage. These include the use of magnetic resonance imaging (MRI) and positron emission tomography (PET scanning) to identify tissues that are abnormally active.
MRI uses a large magnet to surround the patient along with radio frequencies and a computer to produce its images.
PET scanning uses signals from radioactive traces to construct images. Laser beam scanning shines a powerful laser beam through the breast, while a special camera on the far side of the breast records the image.
Researchers are also striving to improve the detection power and diagnostic accuracy of mammography.
Digital mammography is a technique for recording X-ray images in computer code, improving the detection of breast abnormalities.
Computer-aided diagnosis, or CAD, uses special computer programs to scan mammographic images and alert radiologists to areas that look suspicious.
Finally, medical researchers are exploring the use of biological tests to detect tumor markers for breast cancer in blood, urine, or nipple aspirates.
Information from the National Cancer Institute
www.cancer.gov.
