The Association between Beta-blockers and Outcomes in Triple Negative Breast Cancer

Breast cancer is the most common type of cancer in women and the leading cause of cancer-related death among women around the world. Many people with breast cancer also have other long-term health conditions—known as comorbidities—such as heart disease. This is partly because breast cancer and heart problems can share similar risk factors, like age, lifestyle, or certain medical conditions.
Some people with heart disease are prescribed beta-blockers, which are medications that help lower blood pressure and reduce the heart’s workload. Interestingly, several studies have suggested that people who take beta-blockers for heart problems may also experience better breast cancer outcomes.

This possible benefit of beta-blockers seems especially important in a form of breast cancer called triple-negative breast cancer (TNBC). TNBC is a fast-growing type of breast cancer that does not respond to common hormone-based treatments. Some breast cancers are affected by different hormones in the body, which can make them grow faster. Hormone therapy uses medicines to either lower the amount of certain hormones in the body or block certain hormones from getting to breast cancer cells. It is often more difficult to treat, and outcomes can be poorer than for other types of breast cancer.

Endocrine therapy (ET) is a cornerstone in the treatment of hormone receptor-positive breast cancer (approximately 60-70% of all). Its primary rationale is to block or reduce the production of hormones, such as estrogen and progesterone, that promote the growth of certain breast cancer cells. By antagonizing hormone receptors or decreasing hormone levels, endocrine therapy can inhibit tumor proliferation, induce tumor regression, and reduce the risk of recurrence. This approach is especially effective in tumors that express estrogen receptors (ER) and/or progesterone receptors (PR), which rely on hormones for growth.
Common endocrine therapies include selective estrogen receptor modulators (e.g., tamoxifen), aromatase inhibitors (e.g., anastrozole, letrozole), and ovarian suppression methods. These approaches are used in localized and advanced breast cancer settings.

Note however, ET is not an option in triple negative breast cancer (approximately 15-20% of all) as tumors not expressing hormone-receptors for estrogen or progesterone do not derive benefit for this kind of therapeutic approach.

Recent research has shown that beta-blockers may help slow the growth of cancer cells and may also strengthen the immune system’s ability to fight cancer. Because the standard treatment for advanced TNBC includes chemotherapy (to kill cancer cells) and immunotherapy (to help the body’s immune system target cancer), it is important to explore whether beta-blockers might improve how well these treatments work.
Our study will investigate whether taking beta-blockers is linked to better outcomes in patients receiving chemotherapy and immunotherapy for advanced triple-negative breast cancer.