At some point, you may have an abnormal finding on a screening mammogram or notice a lump or change in your breast. To learn whether or not it’s breast cancer, you’ll have follow-up tests.
In many cases, breast cancer can be ruled out with additional breast imaging. This may be a diagnostic mammogram, a breast ultrasound, or a breast MRI.
If breast cancer can’t be ruled out after this additional imaging, you’ll need to have a biopsy. A biopsy removes cells or tissue from the suspicious area of the breast. A pathologist studies the cells or tissue under a microscope to see if cancer is present.
A biopsy is the only test that can diagnose and confirm breast cancer.
Learn more about follow-up after an abnormal mammogram or clinical breast exam.
Most biopsies don’t show cancer
Although a biopsy can be scary, most breast biopsies in the U.S. don’t show cancer .
Still, a biopsy is needed to know whether or not something is breast cancer.
If breast cancer is found, it can be treated. With standard treatment, most people with early-stage breast cancers have a good prognosis (high chance of survival).
Learn about breast cancer treatment.
Types of breast biopsies
The main types of breast biopsies are:
- Needle biopsies. A doctor removes tissue or cells with a needle.
- Surgical biopsies. A surgeon makes a cut (incision) in the breast and removes tissue.
A core needle biopsy (a type of needle biopsy) is the standard and preferred way to diagnose breast cancer. In rare cases, a surgical biopsy may be needed for diagnosis.
Can a biopsy miss breast cancer?
Although it’s rare, a biopsy can miss breast cancer.
How can a needle biopsy miss breast cancer?
A needle biopsy can miss breast cancer if the needle takes a sample of tissue or cells from the wrong area. To limit this problem with core needle biopsies, health care providers use imaging to guide the biopsy. This involves a localization procedure using a wire, radioactive seed or other marker before the biopsy.
Even when samples are taken from the correct area, false negative results can occur if the pathologist misinterprets the tissue or cells as benign (not cancer) when in fact, cancer is present. This is very rare.
A needle biopsy can also miss breast cancer if there’s a problem with the quality of the sample or the pathologist can’t do the necessary tests or can’t interpret the results.
How can a surgical biopsy miss breast cancer?
With surgical biopsies, it’s less likely breast cancer will be missed.
However, a surgical biopsy can miss breast cancer if the wrong area of tissue is removed. To limit this problem, health care providers use:
- Imaging to guide the biopsy (this involves a localization procedure using a wire, radioactive seed or other marker before the biopsy)
- X-rays of tissue samples after the biopsy
Getting a second opinion
Breast cancer is complex. You may want to get a second opinion before your biopsy, or after, when you have the results.
Most health plans allow you to get a second opinion if the second doctor is in your health plan’s network.
Learn more about getting a second opinion.
Breast biopsies don’t cause cancer to spread
Surgical and needle biopsies don’t cause breast cancer to spread [2-4]. Exposing breast cancer to air during surgery or cutting through the cancer doesn’t cause it to spread [2-4].