How is breast cancer diagnosed?

Whether you notice concerning breast changes yourself, or a doctor sees something concerning in a routine screening or appointment, a breast cancer diagnosis will begin with a doctor’s exam to look for any signs and symptoms of breast cancer. Should your doctor discover a lump or a mammogram detect an area of abnormal breast tissue, your doctor may recommend additional tests like an ultrasound or magnetic resonance imaging (MRI).

Ultrasound can confirm whether the lump is a solid tumor or a fluid-filled, noncancerous cyst. It can also be used to assess any abnormal areas found on a mammogram.

Although it is not routinely performed, MRI may be used to assess abnormalities on a mammogram, get a more accurate estimate of a cancer's size, and check for other cancers.

If the lump is solid, your doctor probably will recommend a breast biopsy. During a biopsy, a small amount of breast tissue is removed and analyzed in a laboratory.

A breast biopsy can be done in different ways. These include:

• fine-needle aspiration, which uses a thin needle to withdraw tissue from the tumor

• large-core needle biopsy, which allows larger pieces of tissue to be removed

• stereotactic needle biopsy, a type of large core needle biopsy that uses special imaging equipment to pinpoint the tissue to be removed

• surgical biopsy, which involves removing all or part of the breast lump.

   

The type of biopsy your doctor chooses will depend on the location of the lump, its size, and other factors.

A specialist called a pathologist will examine the tissue under a microscope to determine whether the tissue contains cancer cells. If it does, the pathologist can determine the type of breast cancer.

Attribution & Disclaimer

Copyright © 2025 by Harvard University. Original work prepared by Harvard Health Publishing in English. 

Want to learn more about how to plan for a better, longer life? 

Talk to a financial advisor today!