Navigating Breast Cancer Care: The Significance of Estrogen and Progesterone Receptor Tests

 The Role of Hormone Receptor Testing in Guiding Cancer Treatment

What do estrogen receptor and progesterone receptor (ER/PR) tests involve?

ER/PR tests involve examining the presence and activity of estrogen and progesterone receptors in cells, typically as part of diagnosing certain types of cancer, such as breast cancer. ER/PR tests aid in guiding the treatment of breast cancer. Oncologists examine receptor proteins binding to specific substances in a breast cancer tissue sample. These tests specifically identify receptors attaching to the hormones estrogen and progesterone. Estrogen and progesterone play crucial roles in female sexual development and reproductive functions, with men also having these hormones in smaller amounts.

Approximately 70 per cent of breast cancers in women involve receptors attaching to estrogen or progesterone, while 80 per cent to 90 per cent of breast cancers in men exhibit these receptors. Breast cancer types by the presence of estrogen or progesterone receptors include:

•  ER-positive (ER+): Cancers with estrogen receptors (ER)
• PR-positive (PR+): Cancers with progesterone receptors (PR)
• Hormone receptor-positive (HR+): Cancers with one or both types of these receptors.

Understanding ER and PR Tests for Breast Cancer Diagnosis and Treatment

What is hormone receptor-positive?

• Hormone receptor-positive (HR+) refers to a characteristic of certain types of cancer, most commonly breast cancer. In the context of breast cancer, the term relates to receptors on the surface of cancer cells that can interact with hormones.
• Breast cancer cells may have receptors for two main hormones: estrogen and progesterone. Tumours that are hormone receptor-positive (HR+) have these receptors on their surfaces. This characteristic is crucial in determining the treatment approach for breast cancer.
• For HR+ breast cancer, doctors often use hormone therapies as part of the treatment plan. These therapies work by blocking the effects of hormones or reducing hormone levels in the body, thereby inhibiting the growth of hormone-sensitive cancer cells.
• Healthcare professionals need to identify the hormone receptor status of breast cancer to tailor the treatment strategy appropriately. This information helps guide decisions about hormone therapies and other targeted treatments.

Why is an ER/PR test necessary?

If you've received a breast cancer diagnosis, undergoing this test is crucial. Determining your hormone receptor status is essential for your oncologist to make informed decisions about your treatment. For individuals with ER-positive, PR-positive, or HR-positive cancer, medications that reduce hormone levels or inhibit hormones from promoting cancer growth can be highly effective. Conversely, if you have HR-negative cancer, these drugs will not be effective.

What occurs during ER/PR testing?

Your oncologist will conduct a breast biopsy to obtain a sample of breast tissue. There are three primary types of breast biopsies:

1. Fine needle aspiration biopsy, which employs a thin needle to extract a sample of breast cells or fluid.

2. Core needle biopsy involves a larger needle for sample removal.

3. Surgical biopsy, a minor outpatient procedure that removes a sample.

What are biopsies?

• A biopsy is a medical procedure that involves extracting cells or tissue from the body. 
• A pathologist, a doctor in tissue examination, examines the sample under a microscope to identify any damage or diseases. 
• Doctors may go for additional tests. Biopsies apply to various body parts. 
• Typically, a biopsy is the definitive test to ascertain if a suspicious area is cancerous, but surgeons can conduct it for other medical reasons.
• Biopsies come in different types. In a needle biopsy, they take a small piece of tissue using a needle through your skin. Other biopsies might need surgery.

What are the typical steps in fine needle aspiration and core needle biopsies?

• You'll either lie on your side or sit on an examination table. The oncologist will cleanse the biopsy site and administer an anaesthetic to ensure you experience no pain during the procedure. Once the area is numb, the provider will use either a fine aspiration needle or a core biopsy needle to extract a tissue or fluid sample from the biopsy site. You might sense a slight pressure as the provider withdraws the sample. Surgeons apply pressure to the biopsy site until bleeding ceases, and your provider will then apply a sterile bandage.
• During a surgical biopsy, a surgeon will create a small incision in your skin to extract all or a portion of a breast lump. This procedure is opted for when a needle biopsy is impractical due to the inaccessibility of the lump.

Which medications does the surgeon need? 

Palbociclib is a targeted therapy used in the treatment of certain types of breast cancer. It is approved to treat advanced or metastatic breast cancer in combination with endocrine therapy, specifically for cases with hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) characteristics. Surgeons classify Palbociclib as a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor. It works by inhibiting the activity of specific proteins involved in cell cycle regulation, thereby slowing the progression of cancer cells.

Is chemotherapy necessary for breast cancer that is hormone receptor-positive?

The necessity of chemotherapy for hormone receptor-positive breast cancer depends on various factors, and the patient should consult a healthcare professional.

Why are hormone receptors vital?

• Hormone receptors, including estrogen and progesterone receptors, are essential proteins on cell surfaces.
• In breast cancer, these receptors, specifically estrogen receptors (ER) and progesterone receptors (PR), influence cancer cell growth and behaviour.
• The presence or absence of hormone receptors guides treatment decisions.
• Hormone receptor status determines the effectiveness of hormone therapies in breast cancer treatment.
• Positive hormone receptor status indicates responsiveness to treatments targeting these receptors.
• Assessing hormone receptor status is critical for devising personalized and effective cancer treatment plans.

What is the primary treatment for breast cancer that is hormone receptor-positive?

The initial treatment commonly involves hormonal therapies. The usual first-line treatment combines an aromatase inhibitor with a CDK 4/6 inhibitor. In cases involving premenopausal women, additional ovarian suppression treatment may also be necessary.

Can hormone-positive breast cancer be cured?

The possibility of curing hormone receptor-positive breast cancer depends on several factors, including the diagnosis stage, the specific characteristics of the carcinoma and the effectiveness of the chosen treatment plan. Many cases of hormone receptor-positive breast cancer respond well to treatment, and individuals can achieve long-term remission or cure. However, it's essential to consult with healthcare professionals for personalized information and guidance based on the specific circumstances of the individual's cancer.

What are the risks?

Risks associated with the biopsy procedure include potential bruising or bleeding at the site, the risk of infection, which can be addressed with antibiotics if needed, and the possibility of additional pain or discomfort, for which your oncologist may recommend or prescribe medication for relief. 

What is the latest therapy for breast cancer that is hormone receptor-positive?

The FDA has approved the use of the oral SERD elacestrant in specific cases of estrogen receptor-positive breast cancer. The U.S. Food and Drug Administration (FDA) has approved elacestrant to treat estrogen receptor (ER)-positive, HER2-negative breast cancer in men and postmenopausal women.