Breast Cancer Diagnosis

During a needle biopsy, doctors withdraw a tissue or fluid sample from a suspicious growth in the breast. Pathologists, doctors who study diseases in a laboratory, examine the tissue under a microscope to determine whether cancer is present.

Doctors may also remove a sample of tissue from nearby lymph nodes to see if they contain cancer. Lymph nodes are small immune system glands throughout the body that trap bacteria and viruses. Breast cancer tends to spread to lymph nodes first.

Our doctors may perform one of two different types of needle biopsy: a fine-needle aspiration or a core needle biopsy. In a fine-needle aspiration, doctors use a small needle to withdraw tissue or fluid from the growth. Doctors use a core needle biopsy, which involves a larger needle, to remove a bigger portion of tissue from a suspicious mass or enlarged lymph node.

Either type of biopsy can be performed in a doctor’s office using local anesthesia. Our doctors use imaging techniques, such as ultrasound and mammography, to guide the placement of the needle.

The tissue removed with a core needle biopsy takes more time to examine than tissue removed via fine-needle aspiration, but it can potentially provide pathologists with more information. For example, they can determine whether estrogen or progesterone is fueling the growth of the cancer and whether the tumor is producing high levels of a protein called human epidermal growth factor receptor-2 (HER2), which helps breast cancer cells grow. This information can help guide treatment.

An open surgical biopsy involves removing all or part of a tumor to study it further. This procedure takes place in the hospital.

Open surgical biopsy may be necessary if a needle biopsy results in an abnormal finding, such as atypical hyperplasia or lobular carcinoma in situ. In this case, further evaluation is needed to ensure cancer is not present. With atypical hyperplasia, there’s an overgrowth of cells in the milk ducts or milk-producing glands. With lobular carcinoma in situ, abnormal cells grow in the lobules, or milk-producing glands of the breast.

After any type of biopsy, our pathologists examine tumor tissue under a microscope to determine if breast cancer is present and, if so, the type. They can also evaluate the lymph nodes to see if the cancer has spread beyond the breast.

Pathologists test tumor tissue for hormonal and genetic features that can help guide treatment decisions.

Estrogen and Progesterone Status

The female hormones estrogen and progesterone can contribute to the growth of breast cancer. In some women, breast cancer cells have receptors, or proteins, on their surface that attach to estrogen, progesterone, or both. Breast cancers that test positive for these receptors rely on these hormones to grow.

Hormone receptor status also allows the doctor to predict the chance of the cancer returning after treatment. Your doctor can tailor your treatment to lower this risk. Hormone therapy is effective in people who have cancer that is estrogen receptor positive, progesterone receptor positive, or both.

HER2 Status

Pathologists can also determine whether a tumor is positive for HER2, a protein that encourages cells to grow. Sometimes breast cancer cells produce high levels of HER2 due to gene amplification, meaning there has been an increase in the number of copies of the HER2 gene. These proteins can be detected on the surface of breast cancer cells.

Women who test positive for high levels of HER2 may be candidates for drugs that target this protein.

Triple Negative Status

If pathologists find that the tumor tissue is not positive for estrogen receptors, progesterone receptors, or HER2, the cancer is referred to as triple negative. Triple-negative cancers are more common in women with BRCA1 mutations than in women with other types of breast cancer.

This form of breast cancer tends to be more aggressive and does not respond to therapies used for estrogen receptor–, progesterone receptor–, and HER2-positive cancers. Chemotherapy, immunotherapy, and experimental medications used in a clinical trial setting may be treatment options.

Ki-67 Status

Ki-67 is a marker of cell proliferation, which means that it can be used to measure the growth level of cancer cells. A high Ki-67 level indicates that breast cancer cells are rapidly growing and dividing. Some estrogen receptor–positive cancers with high Ki-67 levels may not respond well to hormone therapies and can be treated with chemotherapy.

Genomic Profiling

Perlmutter Cancer Center doctors can evaluate the presence and activity of proteins, hormone receptors, and genes, such as HER2, that are involved in the initiation, growth, proliferation, and spread of breast cancer cells.

This information can help doctors determine the risk of cancer returning after surgery. It can also help them decide whether to recommend specific systemic therapies, such as hormone therapy, chemotherapy, immunotherapy, or HER2-targeted drugs. Based on the molecular features of the tumor, you may also be eligible to participate in a clinical trial to test new therapies.