A screening test is a procedure done on a person who is asymptomatic meaning they have no signs or symptoms of a disease or condition. A diagnostic test is done to confirm an abnormality on a screening test or because a person has presented to the doctor with symptoms of a condition. Sometimes the same tests are used.
Types of tests
A clinical breast exam (CBE) is an examination of the breast by a medical practitioner that involves them touching a woman’s breast following a specific protocol to feel for lumps or thickening of the skin as well as looking at a woman’s breasts for obvious abnormalities. In the Cayman Islands it is recommended that a woman have a CBE annually or at least once every two years.
A mammogram is a low-dose x-ray of the breast used to detect and evaluate breast abnormalities both in women who have no signs or symptoms (screening) and those with symptoms (diagnostic).
In recent years, digital systems have been introduced and while they still involve x-ray radiation the quality of the image has improved, resulting in more accurate imaging.
Mammograms are sensitive meaning they are effective in detecting breast cancer, often finding cancerous lumps that are too small to feel. As with all screening tests, it is possible that cancer is present but not detected by the mammogram, a false negative result or alternatively that an abnormality is detected that upon additional testing is not cancerous (a false positive result).
Screening mammograms typically involve two views of each breast whereas a diagnostic mammogram involves multiple views of the breast being examined.
The National Cancer Institute has concluded that screening mammography in women aged 40 to 70 years decreases deaths from breast cancer. Other studies have shown benefits of mammography in women over the age of 70. Guidelines for screening mammograms vary between countries. In the Cayman Islands it is recommended that women aged 40 and older have a mammogram every two years or as recommended by their doctor.
Magnetic resonance imaging (MRI) uses radio waves and strong magnets. The energy from the radio waves is absorbed and then released in a pattern formed by the type of tissue and disease. A computer converts these waves into a detailed image of the part of the body being examined. Sometimes a special contrast material is administered to the patient to better see details.
There is some evidence to suggest that screening with MRI along with an annual mammogram is beneficial for women at high risk.
MRI is also used for women who have been diagnosed with breast cancer to determine the size of the cancer and if other cancers are present in the breast.
Ultrasound uses high-frequency sound waves to outline the part of the body being examined and these are echoed back. The echo is picked-up by the ultrasound probe and is converted into an image on a computer screen. Ultrasound is usually used in the diagnosis of breast conditions although it is occasionally used as a screening tool.
Ultrasound can distinguish between cysts (fluid-based) and solid masses. Ultrasound is also helpful along with a mammogram in screening women with dense breast tissue.
Biopsy is specific to diagnosis and involves the removal of a sample of tissue. It is the only way to confirm a cancer diagnosis. There are several types of biopsy and your doctor will discuss the best type of biopsy for you should you require one.
For more information contact the Cayman Islands Cancer Society at 949-7618 or email [email protected].