Breast Cancer Pathology

Breast cancer patients see many doctors during the course of their treatment, but rarely do they meet the specialist who plays a critical role in their outcome: the pathologist who diagnoses their cancer by analyzing samples of tissue. Precise diagnosis is what drives all subsequent decisions about treatment and other patient choices.

Our pathologists are highly specialized and focus not just on cancer—but specifically on breast cancer. They review all of the pathology slides from your biopsy (whether it was performed at Roswell Park or by an outside provider) and render an expert opinion on the key characteristics that will define your breast cancer treatment.

If you have breast cancer, our pathologists will study the cancer cells from your biopsy to pinpoint the exact type and the grade of your cancer. This information tells your physicians how aggressive your cancer is; which treatments your cancer will likely respond to; and the likelihood of your cancer recurring.

These tests include:

A genetic assessment of a patient’s cancer type offers an individualized approach to treatment. Dr. O’Connor and the breast team use this advanced tool to ensure successful outcomes for breast cancer patients.

  • Estrogen and progesterone receptor test: Cancer cells that have an abnormal amount of estrogen or progesterone receptors (binding sites on the cells) mean that drugs that block estrogen can be an effective part of treatment for these cancer types.
  • Human epidermal growth factor type 2 receptor (HER2/neu): This measures how many HER2/neu genes there are and how much HER2/neu protein is in the cancer. Drugs that directly attack HER2, ususally given with other chemotherapy drugs, can be an effective part of treatment for HER2-positive cancers.
  • Multigene tests: These tests look at several genes in the tissue sample to determine whether you are at low, intermediate or high risk for having your cancer recur. If you’re at high risk, adding chemotherapy to your treatment plan may help lower that risk. Women at low risk likely will not benefit from chemotherapy and do not need this treatment. Commonly used tests include Mammaprint® and Oncotype DX,® but these tests are not useful in all cases.

Your Breast Cancer Pathology Report

You may have more than one pathology report. For example, one report will be prepared after your biopsy. Another may be prepared after testing tissue that was removed in surgery. Key findings that may be detailed in your pathology report include:

  • Breast cancer cell type: Refers to where the cancer cells began, such as ductal or lobular.
  • Whether your cancer is invasive or noninvasive
  • Whether your cancer tests positive or negative for:
    • Estrogen or progesterone receptors
    • HER2 protein or gene number
  • Lymph node status: Refers to whether or not lymph nodes contain cancer.
  • Cancer grade: A score of 1 to 3 refers to how different the cancer cells look from normal cells. A score of 1 is low grade meaning the cells look most like normal cells and 3 is high grade with cells that appear very different from normal cells. Grade 2 is in between. In general, Grade 1 and 2 cancers are less aggressive, while Grade 3 cancers have a slightly higher chance of spreading.

Learn more about how to read your pathology report