Geisinger: Screening Versus Diagnostic Mammogram

Early detection remains the most effective defense against breast cancer. Regular mammograms save thousands of lives each year — and have the potential to save even more.

A mammogram is a low-dose X-ray examination that can identify abnormal changes in breast tissue that are not detectable through a physical breast exam. These screenings play a vital role in detecting and diagnosing both breast cancer and benign (non-cancerous) conditions that may cause lumps, skin changes, or other abnormalities. When breast cancer is detected in its earliest, localized stages, the five-year survival rate reaches 99%.

Women are advised to begin annual mammograms at age 40, or earlier if risk factors are present. There are two primary types of mammograms — screening and diagnostic. Although both use the same specialized X-ray equipment, they serve distinct purposes. Understanding the difference between them empowers individuals to take proactive steps toward maintaining optimal breast health.

What Is a Screening Mammogram?

A screening mammogram is an annual X-ray examination performed to check for early signs of breast cancer in women who have no symptoms, such as lumps, skin dimpling, nipple discharge, or noticeable changes in breast size or shape since their last exam.

The primary goal of a screening mammogram is early detection — identifying potential signs of breast cancer before any visible or physical symptoms appear. Because some types of breast cancer can grow and spread rapidly, finding cancer at an early stage, when it is small, significantly increases the likelihood of successful treatment.

During a screening mammogram, a certified technologist positions the breast between two plates that gently compress the tissue to capture clear and detailed images. Typically, two images of each breast are taken from different angles, though additional images may be needed depending on breast size to ensure all tissue is included. The exam generally takes between 15 and 20 minutes.

After the images are taken, a diagnostic radiologist reviews them for any signs of abnormality and sends a report to the patient’s physician. Within about a week, the patient receives a letter indicating one of two outcomes: either the mammogram results were normal, or something was detected that requires further evaluation.

What Is a Diagnostic Mammogram?

A diagnostic mammogram is a specialized imaging test used to investigate the cause of breast symptoms or to further examine an abnormality found during a screening mammogram. It is also performed for women who have previously been treated for breast cancer, particularly within the first five years following treatment, to monitor for any signs of recurrence or new concerns.

During a diagnostic mammogram, the technologist captures images as directed by the radiologist to closely evaluate the area of concern or the specific symptoms being experienced. This examination is more detailed than a screening mammogram and typically includes additional views of a particular region of the breast. In some cases, advanced imaging techniques or a breast ultrasound may also be performed to provide a clearer, more precise look at the tissue.

Because diagnostic mammograms are more comprehensive, they generally take longer to complete. However, results are typically available during the same visit. After reviewing the images, the radiologist may share one of several possible outcomes:

• There is no cause for concern, and the patient can resume regular annual screening mammograms.
• The findings are likely benign, but a follow-up mammogram in about six months is recommended to ensure no changes occur.
• The results suggest the possibility of breast cancer, and a biopsy is needed for a definitive diagnosis.

Being called back for a diagnostic mammogram does not necessarily indicate the presence of cancer. It simply means that the healthcare team wants to take a closer look at a specific area. In most cases, the findings turn out to be non-cancerous.

The recommended age to begin annual mammogram screenings is 40. However, individuals with a family history of breast cancer or other risk factors should consult their physician to determine whether earlier screening is appropriate.

In addition to routine clinical breast exams, yearly mammograms remain the most effective way to take proactive control of breast health. Regular screenings can identify potential issues before symptoms appear, significantly improving the chances of early detection and successful treatment.

Anyone who notices changes in their breasts—such as lumps, skin dimpling, nipple discharge, or alterations in size or shape—should contact their doctor promptly, even if a recent screening mammogram showed normal results. Detecting breast cancer at an early stage allows for more effective treatment and, in many cases, less invasive options.

For ongoing health and wellness guidance, visit geisinger.org/balance.

Dr. Anne Dunne is a board-certified and fellowship-trained radiologist.