Breast cancer is identified in many women during a routine screening mammogram. Other women go to their doctor after they notice symptoms of breast cancer during a regular monthly self-exam. Catching breast cancer early improves the chances of treating it effectively.

Women suspected of having breast cancer are usually referred to a specialist in cancer known as an oncologist. Specialists who treat breast cancer include medical oncologists, surgical oncologists, radiation oncologists, geneticists, and plastic surgeons. Multiple specialists often work together as a team to treat breast cancer. A medical oncologist is usually the doctor who diagnoses breast cancer and manages the treatment process.

How Is Breast Cancer Diagnosed?

Breast cancer is usually diagnosed quickly after a suspicious mass is identified. Since treatment is more effective the earlier the breast cancer is diagnosed, most doctors will want to schedule tests as soon as possible.

Tests and What They Show

Imaging scans can show the shape, size, and location of potential tumors, but only a biopsy and pathology report can provide conclusive results on whether tissue is breast cancer or not. Laboratory exams, genetic tests, blood tests, and other tests help the oncologist better understand what type of breast cancer it is as well as its stage and grade.

Imaging Tests

Only about 20 percent of breast tumors are cancerous (also known as invasive or malignant). If a tumor is felt during self-exam or identified by a screening mammogram, it is not necessarily breast cancer. Imaging tests are often the first step in checking a suspicious lump. The results of an imaging test may make a diagnosis of breast cancer more likely or less likely.

The most common imaging test used for suspected breast cancer is a diagnostic mammogram. Both screening and diagnostic mammograms use X-rays to image the tissue of the breast. In a diagnostic mammogram, the technician takes many more images of the breast including more angles and views. Other imaging tests used to diagnose breast cancer can include ultrasound and magnetic resonance imaging (MRI). Imaging tests are painless.

Biopsy

If breast cancer was not ruled out by the results of imaging exams, the doctor will likely perform a biopsy. Taking a biopsy – a sample of suspected cancer cells – is the only certain way to diagnose breast cancer. There are several techniques used to biopsy breast tissue. Lymph nodes in the chest or under the arm may also be biopsied to check for any trace of cancer cells.

Needle biopsy is one of the most common and least invasive methods for breast biopsy. First, your breast will be numbed. A hollow needle will be inserted one or more times into the breast to remove tiny amounts of breast tissue. Needle biopsy may be uncomfortable, but it leaves no scar.

If needle biopsy is inconclusive, the doctor may perform an incisional or excisional biopsy. In these types of biopsy, you will receive medication to sedate you. The doctor will use a scalpel to cut into the breast. Incisional biopsy removes a smaller piece of tissue. Excisional biopsy is more involved; the doctor will remove a larger piece of cancerous tissue along with a rim of normal tissue around it. Incisional and excisional biopsies usually leave a scar.

Laboratory Testing

Biopsied tissue will be examined in the pathology lab. The pathologist will view the tissue samples under the microscope to determine whether it is cancerous, and if so, what grade the tumor should be assigned.

If the tissue is cancerous, the cells will be analyzed to determine whether they are positive or negative for estrogen, progesterone, or human epidermal growth factor receptor 2 (HER2) receptors. The results of this analysis decide the molecular subtype of the cancer.

Genomic tests such as Oncogene DX will evaluate genes in the cancer cells and provide detailed predictions about how the tumor is likely to grow, how effective some treatments will be, and the odds of the tumor returning later on.

Results of the biopsy, pathology, and Oncogene DX reports provide vital information the oncologist needs to stage the tumor and make recommendations on which treatments will be most effective.

Blood Tests

The doctor may order blood tests to check the function of your bone marrow, liver and kidneys. Blood tests may also check for hepatitis. If the test results show any problems, it may influence the doctor’s treatment recommendations.

Condition Guide

• Breast Cancer – An Overview
• Breast Cancer: Stage and Grade
• Breast Cancer Symptoms
• Breast Cancer Treatment
• Side Effects of Breast Cancer Treatments
• Types of Breast Cancer
• What Causes Breast Cancer?

Resources

External resources

• Breast Cancer Diagnosis – National Breast Cancer Foundation
• Diagnosing Breast Cancer – Susan G. Komen
• Diagnosis – Mayo Clinic
• Mammograms – American Cancer Society
• Symptoms and Diagnosis – Breastcancer.org
• Breast Cancer: Diagnosis – Cancer.net
• Breast Cancer Tests: Screening, Diagnosis, and Monitoring – Breastcancer.org
• Doctors Who Treat Breast Cancer – Cleveland Clinic
• Oncotype DX Test – Breastcancer.org

MyBCTeam resources

• Finding a New Normal: Living With Breast Cancer (Infographic)
• What was the stupidest thing someone said to you when you announced your diagnosis? (Q+A)
• How public are you about your cancer diagnosis? (Q+A)
• What's the biggest lifestyle change you have made since being diagnosed? (Q+A)