Breast imaging is significant in the early detection and diagnosis of breast cancer. However, not all breast imaging procedures are the same. Different clinical conditions are used for mammography, ultrasound, and MRI depending on a person’s age, breast density, symptoms, and risk for breast cancer. Knowing when to conduct any of the imaging tests is critical for women to understand their breast health and seek help in good time.
Mammogram: An important tool for breast cancer screening
A mammogram is an X-ray test of the breast that detects suspicious changes, such as small lumps, distortions, and groups of calcium deposits known as microcalcifications. One of the main benefits of this test is its ability to detect small changes that a routine exam may miss.
Mammography testing is commonly used in screening for breast cancer in women with no symptoms. The suitable age to start screening and the frequency of tests should be based on local recommendations, risk factors, and the woman's health status. Women at average risk are usually advised to seek routine mammography starting at age 40, while women with a very strong family history and serious risk should take into account individual recommendations. Mammography may be less effective in women who have denser breast tissue, which is more frequent in younger women. Denser tissue can confuse abnormality detection, but it is still helpful in younger women when necessary, and age should not be a factor in avoiding this procedure.
Ultrasound: Evaluating a breast lump
Breast ultrasound uses sound waves to generate images of breast tissues without exposing a patient to ionising radiation. This procedure is particularly beneficial in assessing a lump and determining whether it is a cyst filled with fluid or a solid structure that requires additional evaluation.
In women younger than 40 years old, ultrasound acts as the initial imaging tool for any emerging breast lump since, in that age group, breast tissues are relatively dense. Depending on the patient’s age, condition, and clinical findings, a mammogram may also be performed. For women above 40 years old, diagnostic mammograms or digital breast tomosynthesis play a vital role in the evaluation of any emerging breast lump, and ultrasound is used to evaluate specific areas of concern or confirm mammogram findings. However, ultrasound has limitations associated with its screening purpose. This is because its accuracy is dependent partly on the operator’s skills, and this method may not be able to identify specific abnormalities such as microcalcifications as effectively as a mammogram would.
MRI: When more detailed imaging is needed
Breast MRI is a diagnostic test that can provide detailed pictures of the breast. MRI may be specifically used when other standard imaging methods do not satisfactorily explain a finding, when there is a need to determine the extent of a known cancer, or when there is suspicion of cancer in more than one place in the breast.
In addition, MRI can be critical for screening women at risk for breast cancer; for example, the method can be used in women with specific genetic mutations or those with a noted high lifetime cancer risk. It may be recommended along with mammography in certain cases after a specific evaluation. However, even though MRI is highly accurate, it can also detect abnormalities that turn out to be benign, which may create the need for further investigations. It is essential to remember that MRI cannot provide a diagnosis of malignancy on its own. Therefore, it should not be used as a replacement for mammography or ultrasound but should be used depending on clinical cases.
Screening vs diagnosis: Understanding the difference
Screening is described as performing tests on asymptomatic individuals to detect potential cancer development at an early stage. As opposed to screening, diagnostic imaging is diagnostic work done to identify symptoms such as a breast lump, nipple secretion, or breast shape change, or to investigate abnormalities found through screening tests. Breast awareness and clinical examination could be beneficial in showing women changes that require intervention. Nonetheless, self-examination and clinical breast examination cannot replace mammography when recommending routine screening. The schedule for imaging must depend on individual risk factors and selected screening guidelines.
Why biopsy remains the final step?
If an abnormality is seen on an imaging test, the doctor may need to order a biopsy to collect tissue for histological examination. This may be done with the help of ultrasound, mammography, or MRI. It should be borne in mind that imaging can suggest, but not verify, that cancer is present. The important conclusion is that mammography, ultrasound, and MRI can complement each other's contribution in breast care. Depending on whether the diagnostic test is done for screening or upon detection of a symptom, the appropriate type of imaging will be recommended after taking into consideration the age, breast density, and breast cancer risk factors.
The author is the director of surgical oncology at the CK Birla Hospital®, Delhi.
The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.
