Androgen Deprivation Therapy (ADT) is a medical treatment primarily used for individuals diagnosed with prostate cancer. The main objective of this therapy is to reduce the levels of male hormones, known as androgens, within the body. Androgens, such as testosterone, can stimulate the growth of prostate cancer cells. By lowering these hormone levels, ADT aims to slow or stop the progression of the disease.
Understanding How ADT Works
Androgen Deprivation Therapy operates by interfering with the body’s natural production or action of male hormones. One primary approach involves suppressing the production of testosterone, which is mainly produced by the testicles. The brain sends signals to the testicles to produce testosterone, and ADT can disrupt this signaling pathway.
Another mechanism of ADT involves blocking the androgen receptors found on prostate cancer cells. Even if some androgens are present, blocking these receptors prevents the hormones from binding to the cancer cells. This action stops the androgen from promoting cancer cell growth and division.
Different Types of ADT Medications
Various classes of medications are utilized in ADT, each targeting androgen activity through distinct pathways. Luteinizing hormone-releasing hormone (LHRH) agonists, such as leuprolide (Lupron) and goserelin (Zoladex), initially cause a temporary surge in testosterone before permanently suppressing its production by the testicles. This initial surge, known as a “flare,” can be managed with other medications.
LHRH antagonists, including degarelix (Firmagon), work differently by directly and rapidly blocking the release of hormones from the pituitary gland that stimulate testosterone production. This approach avoids the initial testosterone surge seen with LHRH agonists. Both LHRH agonists and antagonists are administered as injections.
Anti-androgens, like bicalutamide (Casodex), enzalutamide (Xtandi), and apalutamide (Erleada), block androgen receptors on prostate cancer cells, preventing androgens from signaling the cells to grow. These medications are taken orally, often in combination with LHRH agonists or antagonists. Abiraterone acetate (Zytiga) is another oral medication that inhibits androgen production outside the testicles.
Common Side Effects of ADT
Reducing androgen levels in the body through ADT can lead to a range of side effects. Hot flashes are a common experience, similar to menopausal symptoms in women, due to hormonal changes. Fatigue is also common, leading to persistent tiredness that can impact daily activities.
Decreased libido and erectile dysfunction are common due to the direct impact of lower testosterone on sexual function. Over time, ADT can contribute to bone density loss, increasing the risk of osteoporosis and fractures. There can also be a reduction in muscle mass and an increase in body fat, which may lead to weight gain. Mood changes, including irritability or depression, can also occur as a result of the hormonal shifts within the body.
Managing Side Effects and Treatment Monitoring
Managing the side effects of ADT involves a combination of lifestyle adjustments and medical interventions. Regular physical activity, including both aerobic and strength-training exercises, can help to mitigate muscle loss, reduce fatigue, and manage weight gain. A balanced diet rich in calcium and vitamin D is recommended to support bone health, and supplements may be prescribed to further reduce the risk of osteoporosis.
Healthcare providers regularly monitor patients undergoing ADT. This monitoring includes checking prostate-specific antigen (PSA) levels to assess treatment effectiveness in controlling cancer growth. Bone density scans, such as DEXA scans, are performed periodically to track bone health. Regular follow-ups allow for timely adjustments to treatment plans or the introduction of therapies to address specific side effects.
When ADT is Prescribed
Androgen Deprivation Therapy is prescribed in various clinical scenarios for prostate cancer, depending on the stage and aggressiveness of the disease. For individuals with advanced metastatic prostate cancer, ADT is a primary treatment to control disease progression and manage symptoms. It helps to shrink tumors and slow the spread of cancer cells throughout the body.
ADT can also be used as neoadjuvant therapy, administered before other treatments like radiation therapy or surgery, to shrink the prostate tumor and make these subsequent treatments more effective. Conversely, it may be used as adjuvant therapy, given after initial treatments, to reduce the risk of cancer recurrence. For prostate cancer that has recurred after initial treatment, ADT can be employed to manage the disease.
References
1. https://www.cancer.org/cancer/types/prostate-cancer/treating/adt-side-effects.html
2. https://www.cancer.org/cancer/types/prostate-cancer/treating/hormone-therapy.html
3. https://www.cancer.gov/types/prostate/patient/prostate-treatment-pdq#_103