An Overview of Breast Cancer Diagnosis

Diagnosing a breast cancer is not a one-step process; it involves testing and procedures to identify changes taking place in the breast that may or may not be cancerous. The process may begin when:

1. During your annual physical, your physician conducts a clinical breast exam and finds a breast abnormality.

2. You make an appointment with your physician or gynecologist after noticing a change in the physical appearance of your breast(s), or finding a lump, a mass, or thickening in your breast. While most lumps are not cancerous, all lumps and thickenings need to be seen and evaluated.

Since not all breast cancers present with a lump, be sure to make your physician aware of any other changes you can see or symptoms you may be having, such as: an inverted nipple, dimpled skin on the breast, red or blotchy skin, increased breast size not related to the menstrual cycle, nipple pain, nipple discharge, breast pain, or swelled lymph nodes in the armpit.

3. Your annual mammogram detects something suspicious for breast cancer.

Once there is a mammogram that indicates something suspicious for breast cancer, your physician or gynecologist may suggest you be seen by a breast surgeon. In each of these situations, you will be referred for additional tests that may include imaging tests and a biopsy.

Imaging Tests: Mammogram, Ultrasound, MRI

A mammogram is an X-Ray image of the breast. Mammograms can detect a number of benign breast conditions as well as identify something suspicious for breast cancer. A mammogram is a key early detection tool that can detect a breast cancer up to two years before it can be felt by you or during a clinical breast exam.

Breast Magnetic Resonance Imaging (MRI)

Magnetic Resonance Imaging (MRI) uses magnetic fields to create an image of the breast. A breast MRI may be recommended to aid in diagnosing breast cancer in some instances. It is not used to detect breast cancer in every woman as it is not as effective as a mammogram for certain breast conditions.


Breast Ultrasound creates images of the breast using sound waves. Frequently used as a follow-up test after a mammogram with an abnormal finding, a breast ultrasound is able to differentiate between a liquid-filled cyst and a solid mass that may or may not be cancer.

While these three imaging techniques can help with diagnosing a breast cancer, a biopsy is the only test that can make a definite diagnosis of breast cancer.

Breast Biopsies

During a breast biopsy a surgeon removes a small tissue sample from the breast that has been identified as having something suspicious for breast cancer. The tissue is tested and examined by a pathologist under a microscope. Biopsies can be performed using a needle or performing a minor surgical procedure.

Needle Biopsies

  • In a fine needle aspiration, a pathologist, who is a medical doctor, a radiologist, or a surgeon withdraws a small amount of tissue from the suspicious area using a fine needle attached to a syringe. The tissue is examined under a microscope. It can give the surgeon information about the lump in question. If the lump is a cyst, the fluid in the cyst can be drained out. If the cells in the lump are cancerous, there may be a need for further tests.
  • A core needle biopsy uses a larger hollow needle than is used in a fine needle aspiration to withdraw small cylinders of tissue from the suspicious area in the breast. It’s more likely to give a clear result because more tissue is taken to be checked than with a fine needle aspiration.
  • The stereotactic core needle biopsy uses x-ray equipment and a computer to analyze pictures of the breast. The computer identifies the exact location, in the area that is suspicious for a breast cancer, where the tip of the needle needs to be inserted.
  • A vacuum-assisted core biopsy involves numbing the skin of the breast and making a small incision of less than a quarter inch in which a hollow probe can be placed and guided to the area suspicious for a cancer using x-rays, ultrasound, or an MRI to extract samples.
  • (MRI)-guided biopsies are used for women with a suspicious area that can only be found by MRI.

A surgical biopsy is performed by a surgeon using either of the following two techniques:

  • An incisional biopsy, in which only part of the suspicious area is removed, allowing just enough tissue to make a diagnosis.
  • An excisional biopsy, which removes the entire tumor or abnormal area.

Following a biopsy, the breast tissue removed during the procedure is sent to a pathologist to examine under a microscope and be tested. If the pathology report confirms the presence of breast cancer, it will also give information about the cancer itself. The report will give the type of breast cancer and its characteristics, such as whether it is invasive or noninvasive, its size, and growth rate as well as additional information, including hormone and genetic status and other factors that will influence treatment planning.

In order to determine if an invasive breast cancer has spread beyond the breast, a surgeon will remove one or more of the lymph nodes located under the arm. The surgeon will do this before or during the surgery to remove the cancer. The nodes will be examined under a microscope and the findings shared with the patient and the care team.

Diagnosing and Staging a Breast Cancer

When test results are completed and reviewed, a breast cancer is staged. Staging is the process of determining the spread of a cancer at the time it is found. The stage of the cancer is the most important factor in developing a plan to treat the cancer and estimating how successful treatment might be.

The most widely used system of categorizing cancer into stages, is the TNM system, which is based on three factors: tumor size, node status, and metastasis. The earliest stage cancers are called stage 0 (carcinoma in situ), and then a range of stages I (1) through an IV (4). Some of the stages are further divided into sub stages using the letters A, B, and C.

A patient may need additional tests to determine the stage, including a chest x-ray, bone scan, CT scan, MRI, and a PET scan. Once all the results are in, the physician reviews them with the patient and explains the staging process. The physician then shares the treatment plan most appropriate for her stage of breast cancer taking into consideration her overall health, age, family history of breast cancer, and risk factors.

Breast Cancer Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

A Word From Verywell

Whether you discover a lump or a medical professional does, don’t let fear or denial keep you from having the tests needed to determine if that lump is a cancer. A wait-and-see attitude, for most of us, just causes nagging anxiety. If it is a cancer, waiting only gives it time to grow and possibly require more aggressive treatment once diagnosed as a cancer.

As a survivor of a primary breast cancer and a second primary breast cancer that occurred 10 years apart, I am able to confirm that regular mammograms can catch early cancers that cannot be felt during a self-exam or during a clinical breast exam. As a result, both my cancers were Stage I invasive cancers that did not require chemotherapy.

My experience in speaking with hundreds of newly diagnosed women and several men during my years as an American Cancer Society patient navigator taught me that:

  • No one is too young or too old to get breast cancer.
  • If you find a lump or other symptom of a breast abnormality, see a physician or gynecologist for a complete examination as soon as possible.
  • If a mammogram indicates something suspicious for cancer, get referrals from a trusted source for a couple of breast surgeons, and get a second opinion.
  • Be a partner in your own care. Be your own advocate. Ask questions. Research potential health care providers, including treatment centers, surgeons, oncologists, and cosmetic surgeons if you choose to have reconstruction.
  • Bring someone with you to hear test results or meet a new health care provider to take notes.
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