Treatment Options for Newly Diagnosed or Recurrent Breast Cancer Subset

The provided transcript delves into the commonly prescribed initial hormone therapies for estrogen receptor-positive, HER2-negative breast cancer, highlighting the importance of treatment selection, the mechanisms of action of various drugs and the factors that guide therapy decisions.

Dr. Gregory Vidal, director of clinical research at West Cancer Center and Research Institute in Memphis, chair of the breast oncology program at One Oncology and associate professor at University of Tennessee Health Science Center in Memphis, discussed the different types of treatments available for patients when they are first diagnosed with breast cancer and the goals of therapy, among other areas, during a session of CURE® Educated Patient® Updates in Metastatic Breast Cancer.

Vidal emphasized the need to determine the first-line treatment for patients with breast cancer, whether they are newly diagnosed or experiencing a recurrence. He also explained the role of estrogen in breast cancer growth, illustrating how estrogen binds to receptors, leading to cell growth.

There are several hormone therapies, including:

• Soltamox (tamoxifen): An old but still effective anti-estrogen therapy that competes with estrogen for receptor binding without activating it.
• Aromatase Inhibitors (Arimidex [anastrozole], Femara [letrozole], Aromasin [exemestane]): These drugs are indicated for postmenopausal women and work by inhibiting the conversion of male hormones into estrogen in the body, effectively reducing estrogen levels.
• Faslodex [fulvestrant]: Similar to Soltamox, it binds to receptors but causes their degradation, effectively blocking estrogen signaling.
• CDK4/6 Inhibitors (Ibrance [palbociclib], Kisqali [ribociclib], Verzenio [abemaciclib]): These drugs work in conjunction with anti-estrogen therapy to inhibit cell growth by targeting multiple mechanisms essential for cancer cell proliferation (cell growth and division).

The transcript also mentions other drugs like Enhertu [trastuzumab deruxtecan], Trodelvy [sacituzumab] and Orserdu [elacestrant], each with specific applications in breast cancer treatment.

The treatment of ESR1 mutated receptors may include options like Soltamox, Faslodex, aromatase inhibitors and CDK4/6 inhibitors. The standard of care for first-line therapy involves a combination of CDK4/6 inhibitors and anti-estrogen therapy, as this approach tends to offer improved disease control and longer survival compared to anti-estrogen therapy alone.

The selection of initial therapy is influenced by several factors:

• Disease stage: The extent and severity of the cancer.
• Menopausal status: Some drugs are suitable only for postmenopausal women.
• Cancer growth rate: The speed at which the cancer is progressing.
• Side effects: The potential impact of the treatment on existing health conditions.
• Patient preference: Whether the patient prefers oral medications or infusions.
• Insurance coverage: The availability of insurance coverage is considered in treatment decisions.

Managing side effects is another important aspect of breast cancer treatment, which can vary depending on the type of therapy. Common side effects include hot flashes, night sweats, vaginal dryness, headaches, nausea, fatigue and more for hormone therapy. CDK4/6 inhibitors may lead to side effects such as nausea, diarrhea, fatigue and blood count issues.

The overarching goal of hormonal therapy is to reduce the risk of breast cancer recurrence and keep the patient free from cancer for as long as possible. However, even with hormonal therapy, there is always a chance of cancer recurrence. Decisions to change therapy are based on factors such as patient tolerance, therapeutic benefits and the tumor’s response. A benefit is not just limited to tumor shrinkage; stable disease, where the tumor does not grow, is also considered a positive outcome. If there is evidence of tumor growth, it indicates the current therapy is ineffective, and a new approach must be explored.

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