Cancer Treatment Centers of America

Why knowing your hormone receptor status is critical in determining breast cancer treatment

CTCA,
Receptor

When Mollie Diggs received her first breast cancer diagnosis, (invasive lobular carcinoma), in 2001, she had no idea of the odyssey to come. Seventeen years later, the 67-year-old New Orleans resident has survived five recurrences of the disease. Each recurrence has shared one commonality: The cancer had abnormally high levels of estrogen or progesterone receptors. Diggs’ hormone receptor status provided her doctor a road map for treatment, and shows the critical roles receptors play in identifying treatment options for some breast cancer patients. 

Breast cells, like many cells in the body, have receptors, or proteins on the cell surface that attach certain hormones to the cell. Healthy breast cells contain receptors for the hormones estrogen and progesterone. Estrogen binds to the cell through the estrogen receptor, which stimulates the breast cells to divide. Sometimes, a mutation, or change in a cell’s DNA, occurs when the cell divides, causing it to grow out of control, leading to cancer.

That's why men don't get breast cancer as often as women. The structure of the breast is the same, but in a man, the breast is not stimulated on a monthly basis by changes in hormones. Before a period, the female breast is sore, tender. That's because of a change in hormone levels.” - Dennis Citrin, MB, ChB, PhD - Medical Oncologist at our hospital near Chicago

Breast cancers that test positive for estrogen or progesterone receptors are known as ER-positive or PR-positive. Additionally, roughly 20 percent of patients have HER2-positive breast cancer, characterized by the presence of the human epidermal growth factor receptor 2 (HER2) in the membrane of the cell. While HER2-positive breast cancers are more likely to metastasize, or spread, and may be more aggressive, advancements in oncology have led to targeted drugs that may better treat the disease. 

Diggs underwent a lumpectomy, a mastectomy, chemotherapy and radiation, but after some years, her breast cancer continued to reappear in the same region of the chest wall. Eventually, Diggs underwent testing to reveal her hormone receptor status—information that Cancer Treatment Centers of America® (CTCA) doctors used to determine her treatment regimen. Certain drugs, for example, are designed to reduce the body’s estrogen levels or block the hormone altogether, preventing it from attaching to cancer cells. This type of treatment, called hormone-blocking therapy, slows or stops the cancer cells from growing or metastasizing. Later on, after she was diagnosed with one of her recurrences, Diggs also tested positive for HER2, and was placed on a drug to target this protein.

 “Despite the fact that there’s been relapse of her disease, Mollie’s story is compelling in that we knew her hormone receptor status, HER2-positive, and there are now a number of approved drugs that treat hormone-sensitive breast cancer,” Dr. Citrin says.

“It’s no exaggeration to say that the recognition of the HER2 protein and the drugs used to attack it are among the biggest advances in breast cancer treatment in the last 20 years,” Dr. Citrin says in his book, “Knowledge is Power, What Every Woman Should Know About Breast Cancer.” He notes that it’s “a relatively small percentage of women who are going to relapse,” calling Diggs a strong example of how advances in cancer treatment, specifically hormone therapy, may stave off even repeated recurrences. “No one can guarantee she’s not going to relapse in the future, but at this moment in time, and for the past two years, she has no evidence of disease.”

Diggs’ survival underscores the significant role hormone receptor status plays in treating many breast cancers, and the power of modern medicine. Hormone therapy is a type of targeted approach that many experts believe represents the future of cancer treatment—targeting the genomic mutations that drive cancer’s behavior, not the part of the body where the cancer formed. Year after year, as researchers have identified specific genomic mutations and developed innovative treatments to target them, outcomes for breast cancer patients have improved. “Every year, 250,000 women are diagnosed with breast cancer, and well over 200,000 of them will have no evidence of disease as a result of modern drug treatment,” Dr. Citrin says.