How effective is hormone therapy for prostate cancer?

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Hormone therapy is also known as androgen deprivation therapy or ADT. It is a type of treatment that works by reducing the level of androgens, or male hormones, in the body because androgens stimulate prostate cancer cells to grow. The main androgens in the body are testosterone and dihydrotestosterone (DHT). Lowering these androgens will make prostate cancers grow much more slowly or even shrink, but they cannot cure prostate cancers.

Hormone therapy is often used when patients cannot have surgery or radiation therapy because cancer has already spread outside the prostate gland. It is used after a surgical procedure when cancer cells recurred or when the doctor suspects that there might be a recurrence. It is also usually used before surgery or radiation therapy to shrink cancer and make it easier for those treatments to work on cancer.

Different Types of Hormone Therapies

Orchiectomy (also known as surgical castration)

It is a type of surgery. However, its effects are a type of hormone therapy. In this kind of procedure, the testicles, which produce most of the androgens in a male body, are removed. Once the testicles are removed, prostate cancers often stop growing or even shrink.

It is the most cost-efficient and the simplest way to reduce androgen levels in the body. However, it is permanent, and many patients can’t deal with the loss of their testicles. Doctors do offer to insert artificial silicone sacs into the scrotum through to appear like real testicles if patients want to look more normal.

Luteinizing Hormone Releasing Hormone (LHRH) Agonists

These drugs lower the amount of testosterone produced by the testicles which cause them to shrink over time until they are often too small to feel. It is sometimes called chemical castration because its effects are nearly identical to orchiectomies. LHRH agonists, which activate the production of LHRH, are injected into the skin or are placed as small implants under the skin.

When treatment is given, testosterone production increases briefly before dropping to low levels. It is called a tumor flare and could be dangerous when cancers have spread to the bone or spinal cord.

LHRH agonist treatments are given as often as once a month to once a year. The most popular variants of this are Lupron, Viadur, Eligard, Zoladex, Trelstar, and Vantas.

Luteinizing Hormone Releasing Hormone Antagonists 

This type of drug works like LHRH agonists but seems to reduce testosterone levels much more quickly but without causing tumor flares like LHRH agonists do. Plenaxis was the first drug for this but was discontinued.

A new LHRH antagonist drug called Firmagon is now being used to treat prostate cancer. Treatments are simply injected under the skin.

Common side effects are some pain and inflammation at the injection site and an increased level of liver enzymes.

Anti-Androgens

Anti-androgens are needed during hormone therapy because a few androgens are still produced by the adrenal glands. These are often taken along with orchiectomies or LHRH agonists.

The most common types of these drugs available on the market are Eulexin, Casodex, and Nilandron and they are taken as pills.

Combined Androgen Blockade (CAB) 

LHRH agonists are sometimes used with anti-androgens to block male hormones better because male hormones such as testosterone increase the growth of prostate cancer cells. This combined treatment is thought by some to be the safest way to start hormone treatment because it reduces the chance of flare-ups. It has not proven to be more effective as permanent therapy though so it is often only given in the first 2 to 3 months of hormone therapy.

Female Hormones

Estrogen can lower testosterone levels, so it is sometimes used as hormone therapy to prevent the growth of prostate cancer cells. Unfortunately, it has some side effects such as heart problems, blood clots, and breast development.

Estrogen is usually given as a pill, but it’s been found that there are fewer side effects when taken as a patch or given as injections.

CYP-17 Inhibitors

This type of hormone therapy prevents androgens from being produced by the body. Aytiga is a type of this that treats castration-resistant prostate cancer when it has spread even after chemotherapy, and the use of other drugs has not worked. It has been shown to improve the survival rate for men with this type of cancer.

Different Strategies 

Treating Early vs. Delayed Treatment 

Some doctors like to start patients off early in hormone treatment because it’s been found to slow down the growth of the disease and lengthen the survival of the patient. However, some doctors believe that waiting a bit may be a more beneficial fixed period because of the side effects and the possibility of cancer becoming resistant to therapy early on.

Intermittent vs. Continuous Therapy 

Most prostate cancers treated with hormone therapy become resistant eventually after a few months or years. Thus, constant androgen (testosterone) suppression is often not advisable. Doctors have been pushing for intermittent treatment in which treatment is stopped when PSA levels drop down. When they begin to rise again, then treatment can be started again.

Another technique is to use androgen (testosterone) suppression for fixed periods of time like six months of therapy, followed by a six-month rest period. An advantage of intermittent treatment is there are fewer reported side effects such as fatigue, impotence, hot flashes and the loss of libido.

Combined Androgen Blockade (CAB)

A study has found that combining combined androgen blockade treatments (a combination of androgen suppression drugs with LHRH agonists) with radiation therapy led to more deaths from prostate cancer than using simply LHRH agonists with radiation. However, other studies have pointed that with advanced cancers, those treated with CAB lived longer than those treated with LHRH agonists alone.

Triple Androgen Blockade (TAB) 

Some doctors have opted to add another drug to combined therapy known as 5-alpha reductase inhibitor to better suppress androgens in the body. It goes by the name of Proscar, Propecia, or Avodart. However, there’s not enough conclusive data to support the use of this drug as yet.

Side Effects of Hormone Therapy

Hormone therapy can come with several negative side effects due to the big changes in the level of hormones in the body. Here are some of the side effects patients should expect:

Reduced libido (this happens less often with anti-androgens)

Impotence

Hot flashes

Growth of breast tissue with some tenderness

Osteoporosis

Anemia

Loss of muscle mass

Weight gain

Fatigue

High cholesterol levels

Depression

Increased risk of hypertension, diabetes, and heart attacks

Problems with cognition such as memory, thinking and concentration

Some important questions to ask your doctor 

Which type of hormone therapy should I take for my case?

When will treatment begin and how often will I have to get treatments?

How will I feel during treatment?

What can I do during treatment to help relieve symptoms?

How will I know if the treatment is working on me?

What side effects should I expect?

How many checkups will I require during treatment?


Dr. Adem Gunes
Dr. Abdullah El-Hossami

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