Hormonal therapy (oncology)

Hormonal therapy in oncology refers to the use of hormones or hormone-blocking agents to treat cancer. This form of therapy is predicated on the observation that certain cancers depend on hormones to grow. By modulating the body's hormone levels or blocking their effects on cancer cells, hormonal therapy can slow or stop the growth of hormone-sensitive tumors. This treatment approach is commonly used in cancers of the breast, prostate, and endometrium.

Mechanism of Action

Hormonal therapy works through several mechanisms, depending on the type of cancer and the specific agents used. In general, these mechanisms include:

• Reducing the production of hormones in the body (e.g., estrogen and testosterone) that can fuel cancer growth.
• Blocking hormone receptors on cancer cells, preventing the hormones from promoting cancer cell growth.
• Altering the metabolic pathways of hormones to less active forms.

Types of Hormonal Therapy

Hormonal therapy can be categorized based on the type of hormone targeted or the mechanism of action. Major types include:

• Estrogen Blockers/Modulators: Used primarily in the treatment of breast cancer, these agents block estrogen receptors or decrease estrogen production. Examples include tamoxifen and aromatase inhibitors like anastrozole.
• Androgen Deprivation Therapy (ADT): This is the cornerstone of prostate cancer treatment and involves reducing testosterone levels or blocking its effects on prostate cancer cells. Methods include surgical castration, LHRH agonists, and anti-androgens.
• Progestins: Used in the treatment of endometrial cancer, progestins can slow the growth of endometrial cancer cells.
• GnRH Agonists and Antagonists: These agents affect the pituitary gland's release of gonadotropins, which can decrease the production of sex hormones.

Indications

Hormonal therapy is indicated for the treatment of hormone receptor-positive cancers, including:

• Breast cancer: Especially for cancers that express estrogen or progesterone receptors.
• Prostate cancer: Most prostate cancers are testosterone sensitive and respond to ADT.
• Endometrial cancer: Particularly in cases that are advanced or recurrent and express progesterone receptors.

Side Effects

The side effects of hormonal therapy vary depending on the specific treatment but may include:

• Hot flashes
• Fatigue
• Mood swings
• Risk of blood clots
• Bone thinning (osteoporosis)
• Changes in sexual function and libido

Conclusion

Hormonal therapy represents a critical component of the oncologic arsenal against hormone-sensitive cancers. By understanding the hormonal dependencies of certain tumors, clinicians can tailor treatments that specifically target these growth pathways, offering a personalized approach to cancer care. Ongoing research continues to refine and expand the use of hormonal therapies, promising improved outcomes for patients with hormone-sensitive cancers.