Breast cancer accounts for 31% of female cancers, and more than half are classified as hormone receptor positive. Receiving a breast cancer diagnosis is a life changing event, and navigating your diagnosis can be scary and challenging. Learning about your cancer and evaluating your treatment options can be overwhelming but increasing your knowledge is empowering. It is important that you understand your treatment options, how they work, and which option may be best for you.

Click here to learn more about an ongoing clinical trial, determine if you are eligible, and do your part to advance estrogen receptor positive (ER+) and human epidermal receptor 2 negative (HER2-) breast cancer research.

Hormones and Receptors

Hormones and receptors play an important role in adjuvant endocrine therapy. The majority of breast cancer diagnoses are either estrogen or progesterone receptor positive. These two hormones are the key components of cancer formation and you will likely hear these terms used frequently.

Estrogen and progesterone receptors are found on the surface of breast cancer cells. When hormones attach to the receptors, cancer cells can grow and divide. Breast cancers that have a high number of estrogen receptors are labeled as estrogen receptor-positive (ER-positive), and cancers with a high number of progesterone receptors are called progesterone receptor-positive (PR-positive). At least 65% of all breast cancers are specifically classified as ER+/HER2-.

The link between hormones and adjuvant endocrine therapy is fundamental to understanding how this treatment approach works in breast cancer treatment.

What is adjuvant therapy?

Adjuvant therapy is additional treatment that is given after your initial or primary therapy such as surgery. There are several different types of adjuvant therapies, and they are commonly used when treating breast cancer. Some examples include chemotherapy, immunotherapy, radiation therapy, targeted therapy, and hormone (or endocrine) therapy. The main goal of adjuvant therapy is to increase the effectiveness of the primary therapy and reduce the risk of the cancer returning by targeting any remaining cancer cells that were not destroyed by the primary treatment.

What is adjuvant endocrine therapy?

Adjuvant endocrine therapy is often referred to as hormone therapy. Hormone therapy for breast cancer is different from hormone therapy used to treat menopausal symptoms. Endocrine therapy for breast cancer is used in patients with hormone receptor-positive breast cancer. It works by targeting hormones in the body, lowering estrogen levels, and stopping cancer growth. It is not effective against hormone receptor-negative cancers. Adjuvant hormone therapy for breast cancer may look different depending on the type of cancer you have.

In women with ER+/HER2- breast cancer, adjuvant endocrine therapy is a key aspect of treatment. Adjuvant endocrine therapy can be given for many years after surgery to reduce the risk of cancer coming back. Research suggests that when adjuvant hormone therapy is initiated after surgery, there is a lower risk of cancer coming back, or new cancer developing somewhere else in the body.

If you have been diagnosed with breast cancer, it is important that you work closely with your healthcare team to determine the most appropriate therapy and treatment plan.

Impact in Black Women

Disparities in breast cancer outcomes exist among different racial and ethnic groups. Breast cancer is the leading cause of cancer-related death among Black women. While breast cancer rates are higher in White women, survival rates are lower in Black women. Black women are more likely to delay breast cancer treatment including adjuvant endocrine therapy which may play a role in these rates. You can eliminate disparities in breast cancer treatment by communicating your concerns with your healthcare provider and considering clinical trial participation.

If you have been diagnosed with early-stage ER+/HER2- breast cancer and have already had surgery to treat the breast cancer, click here to learn more about whether a clinical trial for endocrine therapy may be an option for you.

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References

• American Cancer Society Journals. CA: A Cancer Journal for Clinicians. Cancer statistics, 2023.
• American Cancer Society. Hormone Therapy for Breast Cancer
• Endocrine therapy for breast cancer in the primary care setting. Curr Oncol. 2018 Aug; 25(4): 285–291.Published online 2018 Aug 14.
• American Cancer Society. Breast Cancer Hormone Receptor Status
• National Cancer Institute. Hormone Therapy for Breast Cancer
• American Cancer Society Journals. CA: A Cancer Journal for Clinicians. Systemic therapy for hormone receptor-positive/human epidermal growth factor receptor 2-negative early stage and metastatic breast cancer
• Racial disparities in breast cancer diagnosis and treatment by hormone receptor and HER2 status. Cancer Epidemiol Biomarkers Prev.

This article is sponsored by Lilly.