Hormonal therapy, also known as endocrine therapy, is a cancer treatment that works by altering the body's hormone levels or blocking the effects of hormones that fuel certain cancers. It is primarily used in hormone-sensitive cancers such as breast cancer, prostate cancer, endometrial cancer, and, less commonly, ovarian and thyroid cancers. Hormones like estrogen, progesterone, and testosterone can promote the growth of some cancers, and hormonal therapy helps slow or stop that growth.

In breast cancer, hormonal therapy is commonly used for tumors that are estrogen receptor (ER) and/or progesterone receptor (PR) positive. Medications like tamoxifen (which blocks estrogen receptors) and aromatase inhibitors (which reduce estrogen production) are used to prevent cancer recurrence after surgery or to manage advanced disease. In prostate cancer, hormonal therapy, also called androgen deprivation therapy (ADT), reduces levels of male hormones (androgens) like testosterone to shrink or slow the growth of the cancer.

Hormonal therapy can be administered in different ways depending on the type of cancer and the treatment goal. It may be given as oral tablets, injections, or even through surgery (like oophorectomy or orchiectomy) to remove hormone-producing organs. The treatment can be used before surgery (neoadjuvant), after surgery (adjuvant), or as the main treatment for advanced or metastatic cancer. It is often part of a long-term treatment plan, especially in breast and prostate cancers, sometimes continuing for five to ten years.

While hormonal therapy is usually well tolerated, it is not without side effects. Since it alters the body's natural hormone levels, it can lead to symptoms like hot flashes, fatigue, mood changes, decreased libido, joint pain, bone thinning, and increased risk of blood clots. The severity and type of side effects vary based on the drug used, duration of therapy, and individual patient factors. Bone health and cardiovascular risk are especially important considerations during long-term therapy.

Hormonal therapy has significantly improved survival and quality of life for many patients with hormone-sensitive cancers. It is most effective when tailored to individual patient profiles, and regular monitoring is necessary to assess the treatment's effectiveness and manage any side effects. A multidisciplinary team, including medical oncologists, endocrinologists, gynecologists/urologists, and primary care providers, works together to ensure optimal outcomes from hormonal therapy.