How Is Breast Cancer Diagnosed?

A breast cancer diagnosis can be overwhelming and often marks a period of time in which you’ll receive many tests.

Doctors will attempt to learn as much as possible through these tests — about your breast cancer type, how far it has advanced, and any other clinical information that will help guide the course of treatment.

All these tests can be very stressful, but they allow doctors to begin treating you as soon as possible.

There are three types of tests related to breast cancer: screening tests, diagnostic tests, and monitoring tests.

In the early stages of possible diagnosis, people can expect to undergo screening tests and diagnostic tests.

Monitoring tests happen later, after diagnosis and the beginning of treatment. They help doctors know how the treatment is working, what changes to the plan may be necessary, and whether the cancer returns after a period of being undetectable.

Screening Tests

Doctors use screening tests to look for possible signs of breast cancer. The most common type of screening test is a mammogram, which uses low-intensity X-rays to create an image of your breast.

A positive screening — one with a suspicious area in your breast — doesn’t mean you have cancer. In fact, the majority of positive screenings are not cancer.

Diagnostic Tests

Doctors use diagnostic tests for people with suspected or possible cancer to determine whether or not they definitely have breast cancer. Diagnostic tests also provide more information about a cancer.

A biopsy is the removal of a tiny amount of tissue or fluid from your tumor or the area where cancer is suspected so that doctors can examine the cells under a microscope. Many people who undergo biopsies do not have cancer. But a biopsy is the main way you can learn whether you have cancer or not.

• The size and location of the suspicious area
• What the suspicious area looks like
• How many abnormal areas exist
• Any other health conditions you have
• Your personal preference

Usually only one biopsy is necessary to diagnose breast cancer. But doctors may need to do additional biopsies if the first one doesn’t provide enough tissue for testing or if they need to run additional tests.

The types of biopsy include:

Core Needle Biopsy

A core needle biopsy uses a wider needle to withdraw tissue from the part of the breast that your doctor thinks looks or feels suspicious or unusual.

Surgical Biopsy

A surgical, or open, biopsy is rarer than fine needle and core needle biopsies. It involves removing all or part of a lump to conduct lab tests on it.

There are two types of surgical biopsies:

• Incisional: During an incisional biopsy, a doctor removes only a portion of the lump or suspicious area.
• Excisional: During an excisional biopsy, the doctor removes the entire suspicious area and may also remove some of the normal breast tissue surrounding the area.

A pathologist will examine and analyze body tissue and cells under a microscope.

If the pathology report reveals cancer, the doctors will first want to determine what stage your breast cancer is and what grade the tumor is.

• Blood tests
• Additional biopsies
• A bone scan
• A chest X-ray
• Breast ultrasound
• Other specialized imaging or chemical testing

One common imaging test is computerized tomography, or a CT scan, that takes cross-sectional X-rays of the body to see if the disease has spread to other areas.

Another common test is positron emission tomography, or PET scans, that look at cell activity. A PET scan involves injecting a person with a tiny amount of sugar substance and radioactive material so cameras can observe highlighted areas in the breast on a computer screen. This test also helps doctors see if the cancer has spread to other parts of the body.

Other names for this type of testing include molecular profiling, next-generation sequencing, and comprehensive genomic profiling. The test looks at the entire genome — the entire set of genetic code in the cells.

Learning what mutations the cancer genes have can help doctors determine whether you receive a targeted therapy or if there is a clinical trial you can enroll in. Targeted therapy kills only the cancer cells with a specific gene or gene mutation.

An estrogen receptor–positive (ER-positive) or progesterone receptor–positive (PR-positive) cancer means that a particular hormone may send signals to the cancer cells to cause them to grow.

Specific medications exist to treat hormone-positive cancers. You will also likely undergo additional testing if you have a hormone receptor–positive cancer.

Doctors will also give you a test to find out if a gene called HER2 (human epidermal growth factor receptor 2) is involved in your cancer. This gene makes proteins called HER2 receptors, which are involved in managing healthy cell activity.

Four tests can be used to determine HER2 status:

• IHC (immunohistochemistry) test
• FISH (fluorescence in situ hybridization) test
• SPoT-Light HER2 CISH (subtraction probe technology chromogenic in situ hybridization) test
• INFORM HER2 Dual ISH (in situ hybridization) test

Undergoing tests can be overwhelming. You can ask your doctor to provide information on resources for support at the time of your diagnosis. These support resources can be especially helpful in the days and weeks immediately after diagnosis, while you schedule and undergo tests and wait for results.

The longer the wait for the results, the greater the anxiety may be. Even after successful cancer treatment, many people still experience bouts of anxiety.

If a doctor thinks there’s a chance you may have breast cancer, there are many different tests they may recommend. The most common test for diagnosing cancer is a biopsy, which takes a sample of tissue for analysis. If a biopsy is positive, doctors will likely request further testing to confirm the presence and type of cancer.