Breast Cancer Diagnosis

A doctor reassures a patient in a sunlit medical exam room. She wears a lab coat and mask and gestures with her hand as she explains a procedure. The mood is optimistic.
With an accurate diagnosis, breast cancer experts like Dr. Alexandra Zimmer can help you get the best treatment.

If you have found a lump in your breast, or if a mammogram shows something suspicious, your provider will ask you to come in for more tests. Accurate diagnosis is the first step in getting the right treatment.

It’s important to know:

  • Most lumps are not cancer.
  • Most mammogram callbacks are false alarms.
  • Either way, cancer should be ruled out.
  • We offer a wide range of support services for you and your family.

What is diagnosis?

Diagnosis is the process of finding out whether you have cancer. And if you do have cancer, diagnosis can tell us:

  • What stage it is
  • What type it is
  • How fast it’s growing
  • What receptors it has
  • Whether it has spread

This information is crucial in deciding the best treatment.


A mammogram is a noninvasive test. It uses X-rays to produce an image of your breast.

If a mammogram shows something unusual, your provider will contact you. This is known as a callback. It’s natural to be concerned if you get a callback. But a major 2017 study found that only 4.4% of callbacks lead to a cancer diagnosis.

If you get a callback, your provider may recommend a follow-up mammogram. This second scan is often called a diagnostic mammogram.

Mammograms can’t always tell if a lump is cancer. To be sure, we may recommend more tests. Learn more about mammograms

Breast ultrasound

Breast ultrasound is a noninvasive test that does not use radiation. It produces an image of your breast using sound waves. It can help us diagnose lumps or abnormalities. It can also show whether a lump is solid or filled with fluid. Learn more about breast ultrasound.

Breast MRI

Magnetic resonance imaging (MRI) is a noninvasive test that does not use radiation. It produces an image of your breast using magnets and radio waves. It can also show if there is an unusual change in your blood vessels, which can be a sign of cancer. Learn more about breast MRI.

Breast biopsy

Biopsy is the most accurate way to test for breast cancer. It is invasive, so it is usually done only if other tests show something unusual.

It’s natural to feel anxious about getting a biopsy. But according to the 2020 edition of Current Surgical Therapy, about 70% of breast biopsies do not find cancer.

In a biopsy, your team takes a tiny tissue sample to look at in a lab for cancer cells. We do three types of biopsy:

  • Ultrasound-guided breast biopsy: We use ultrasound to see inside the breast. Your team guides a needle into your breast to take a tissue sample.
  • MRI-guided breast biopsy: We use magnetic resonance imaging to see inside the breast. You lie on a scanner. Your team guides a needle into your breast to take a tissue sample.
  • Stereotactic-guided breast biopsy: We use low-dose X-rays to see inside the breast. You sit with your breast in the mammogram machine. Your team guides a needle into your breast to take a tissue sample.

After doctors look at the sample, they write their findings in a pathology report. Your provider will share and discuss the report with you.

This drawing depicts lymph node biopsy in three panels. In the first panel, a radioactive dye is injected into a tumor in the breast. Next, a probe is inserted near the armpit to biopsy two lymph nodes. Finally, the tumor and two lymph nodes are removed.
You might need a biopsy to see if breast cancer has spread to the lymph nodes.

Lymph node biopsy

If you are diagnosed with breast cancer, you might need a lymph node biopsy.

Lymph nodes are bean-size structures located throughout your body. They filter a fluid called lymph that circulates through your body to fight infection and flush waste. Lymph nodes often trap cancer cells that have spread from your breast.

A biopsy can show if any cancer has spread. It can also identify any lymph nodes that need to be removed. We do two types:

  • Ultrasound-guided core biopsy. We use ultrasound to look at a lymph node. Your team guides a needle to the node to take a sample.
  • Ultrasound-guided fine needle aspiration. Your team guides a fine needle into a node and takes a smaller sample.

Learn more

For patients

Call 503-494-4673 to:

  • Make an appointment
  • Seek a second opinion
  • Ask questions


OHSU Breast Center, South Waterfront

Center for Health & Healing, Building 2, ninth floor
3485 S. Bond Ave.
Portland, OR 97239

Free parking for patients and visitors

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