Hormone therapy, also called androgen-deprivation therapy (ADT), reduces the effect of male hormones such as testosterone, which can stimulate the growth of prostate cancer.
ADT is used in several situations. It may be combined with radiation for some intermediate- and high-risk localized cancers, and it is a major treatment for prostate cancer that has spread beyond the prostate.
Hormone therapy can be very effective at controlling prostate cancer, but it can also have significant side effects, particularly when used for long periods. These can include hot flashes, loss of muscle and bone, weight gain, metabolic changes, fatigue, and sexual side effects.
For men who need ADT, an important question is not only whether to use it, but which treatment to use and for how long.
Prostate cancer cells usually depend on androgens, particularly testosterone, to grow. Hormone therapy works by reducing testosterone levels or blocking the ability of cancer cells to use testosterone.
Several types of medications can accomplish this. Some reduce the body's production of testosterone, while others block androgen receptors on prostate cancer cells.
ADT does not usually eliminate prostate cancer by itself. Instead, it can shrink the cancer, slow its growth, and make other treatments such as radiation more effective.
For advanced prostate cancer, newer medications that more completely interfere with androgen production or signaling are often combined with traditional ADT to improve cancer control.
Hormone therapy can play different roles depending on the stage and risk level of prostate cancer.
For some men with intermediate- or high-risk localized prostate cancer, ADT is given for a period of time along with radiation. Lowering testosterone can make the cancer more sensitive to radiation and reduce the risk of recurrence.
For cancer that has spread beyond the prostate, hormone therapy is one of the main treatments. It can often control the disease for a substantial period of time.
ADT may also be used when prostate cancer returns after surgery or radiation, depending on the PSA level, imaging results, and other characteristics of the cancer.
Because the benefits and side effects depend partly on how long ADT is used, the appropriate duration is an important treatment decision.
Because testosterone affects many tissues throughout the body, lowering it can produce significant side effects. These vary with the type and duration of treatment.
Common effects include hot flashes, fatigue, loss of sexual desire and erectile function. Over time, ADT can also cause loss of muscle mass and bone density and an increase in body fat.
Hormone therapy can affect metabolic health as well. It may worsen insulin sensitivity, blood sugar, cholesterol, and cardiovascular risk factors.
Exercise—particularly resistance training combined with aerobic activity—can help preserve muscle, strength, bone health, and physical function. Attention to nutrition, weight, and cardiovascular health is also important.
Men receiving long-term ADT should discuss bone health, metabolic health, exercise, and cardiovascular risk with their medical team rather than focusing only on the cancer itself.
Hormone therapy can cause loss of bone density and muscle, particularly when it is used for an extended period. Protecting bone and muscle health should therefore be part of the discussion when starting ADT. For men receiving longer-term hormone therapy, doctors may also recommend bone-density testing (DEXA) to monitor for osteoporosis.
Adequate calcium and vitamin D are important for bone health. Calcium can be obtained from food, but supplements may be necessary if dietary intake is inadequate. Vitamin D needs vary, and a blood test can help determine whether supplementation is appropriate.
Supplements should not be assumed to prevent or treat prostate cancer. Some can also interact with medications or cancer treatments, so it is a good idea to discuss supplements with the medical team.
Just as important as supplements is regular resistance and weight-bearing exercise, which can help preserve muscle strength and bone density during hormone therapy.
The appropriate duration of hormone therapy depends on the risk level of the cancer, the treatment being used with it, and the individual patient.
When ADT is combined with radiation, some men may need it for only several months, while men with higher-risk disease may benefit from a longer course.
This matters because the side effects of ADT generally become more important with longer treatment. Researchers continue to study whether some patients can receive shorter courses without reducing the effectiveness of their cancer treatment.
For this reason, it is reasonable to ask: What benefit is expected from this length of hormone therapy, and is a shorter duration appropriate for my particular cancer?
After hormone therapy is stopped, testosterone may gradually recover, but the timing varies considerably.
Recovery depends on factors such as age, testosterone level before treatment, the type of ADT used, and how long treatment continued. After a shorter course, testosterone may recover within months, while after prolonged treatment recovery can take considerably longer. In some men, testosterone may not return fully to its previous level.
As testosterone returns, some ADT side effects—including energy, muscle strength, sexual function, and body composition—may improve.
Men finishing ADT can ask whether their testosterone and PSA should be monitored together during recovery.
An especially useful discussion of how long hormone therapy may be necessary when used with radiation.
PCRI explains how hormone therapy is used for high-risk prostate cancer and discusses common side effects and ways they may be managed.
PCRI discusses practical ways to manage common side effects of hormone therapy, including fatigue, hot flashes, loss of muscle and bone strength, weight gain, and metabolic changes.
PCRI explains what men can expect as testosterone recovers after hormone therapy and discusses the factors that may influence how quickly and completely it returns.