Aromatase Inhibitor

• Aromatase Inhibitors (AIs) are a vital treatment for hormone-receptor-positive breast cancer, especially in postmenopausal women.
• They function by blocking the aromatase enzyme, which converts other hormones into estrogen.
• By lowering estrogen levels, AIs help prevent cancer recurrence and slow disease progression.
• Common side effects include joint pain, hot flashes, and an increased risk of bone thinning.
• Regular monitoring and supportive care are essential to manage potential side effects during treatment.

What is an Aromatase Inhibitor and How Does It Work?

An Aromatase Inhibitor refers to a type of medication that plays a crucial role in endocrine therapy for certain cancers. These drugs specifically target and block the enzyme aromatase, which is responsible for converting androgens (male hormones) into estrogens (female hormones) in various tissues throughout the body.

The aromatase inhibitor mechanism involves inhibiting this enzyme, predominantly found in fat tissue, muscle, skin, and breast cancer cells. By blocking aromatase, these medications effectively lower the overall estrogen levels circulating in the body. This reduction is particularly significant for postmenopausal women, whose primary source of estrogen comes from this peripheral conversion rather than ovarian production. Lowering estrogen deprives hormone-receptor-positive breast cancer cells of the estrogen they need to grow, thus slowing or stopping their proliferation. There are two main types of Aromatase Inhibitors: non-steroidal inhibitors (e.g., anastrozole, letrozole) which reversibly bind to the enzyme, and steroidal inhibitors (e.g., exemestane) which irreversibly inactivate it.

Uses and Potential Side Effects of Aromatase Inhibitors

The primary aromatase inhibitor uses are in the adjuvant treatment of hormone-receptor-positive breast cancer in postmenopausal women, as well as in the treatment of advanced or metastatic hormone-receptor-positive breast cancer. By reducing estrogen levels, AIs can prevent cancer recurrence and slow the progression of existing disease. According to the American Cancer Society, approximately 2 out of 3 breast cancers are hormone receptor-positive, highlighting the critical role of AIs in managing a significant portion of breast cancer cases.

While highly effective, Aromatase Inhibitors can lead to a range of aromatase inhibitor side effects, which are often related to the significant reduction in estrogen levels. These side effects can mimic or exacerbate menopausal symptoms and vary in intensity among individuals. Common side effects include:

• Joint and muscle pain (arthralgia and myalgia)
• Hot flashes and night sweats
• Fatigue and lethargy
• Bone thinning (osteoporosis) and an increased risk of fractures
• Vaginal dryness and discomfort
• Hair thinning
• Mood changes and depression

To mitigate some of these effects, patients undergoing AI treatment are often advised to engage in regular weight-bearing exercise and ensure adequate intake of calcium and vitamin D to support bone health. Regular bone density scans, such as DEXA scans, are also recommended to monitor for osteoporosis. It is crucial for patients to discuss any side effects with their healthcare provider, as management strategies can often improve quality of life during treatment.