Breast Cancer Diagnosis

Our doctors use a number of tests and procedures to diagnose cancerous changes in the breast. These include:

  • medical history
  • physical exam
  • imaging tests such as mammogram, ultrasound, and MRI

If your doctor finds signs of breast cancer, we may perform other tests, including a biopsy, to find out more information about what type of cancer it is and how far it has advanced. A biopsy is the only test that can make a definite diagnosis of breast cancer.

A biopsy also provides information about the markers of the cancer, which determine the drugs that should be used to treat it. Not all breast cancers are the same, and they aren’t all treated in the same way. So it’s important for your healthcare team to have this information before pursuing a treatment plan.

Memorial Sloan Kettering experts describe efforts to improve our understanding — and treatment — of breast cancer.

We regularly measure the levels of the estrogen receptor (ER) and progesterone receptor (PR) in the tissue sample taken from the cancer. The amount of ER and PR that are present in invasive breast cancer can be used to predict how the tumor will respond to treatments that lessen the hormones in your body. (Examples of these are tamoxifen and aromatase inhibitors.)

We also routinely measure the presence of a protein called human epidermal growth factor-2 (HER2) in invasive carcinoma. This can also have an effect on treatment options.

Sometimes, the biology of a breast tumor changes if it metastasizes (spreads) to another part of the body. Your doctor may want to take another biopsy to re-check markers at that time. We can also perform more-specialized testing that can help us determine whether you would benefit from clinical trials that test new targeted treatments.