Hormone Treatment for Prostate Cancer – 2

In the second part of our hormone treatment article, we discuss drugs called antiandrogens. Androgen hormones, crucial for prostate cell growth and proliferation, act by binding to proteins called androgen receptors on the cell surface. Antiandrogens prevent androgens from binding to these receptors.

The most widely used drugs in this group are Flutamide (Eulexin) and Bicalutamide (casodex).

They are taken as daily pills. Antiandrogens are generally not used alone, but often added when LHRH agonist effectiveness decreases. They are also used for several weeks when first using LHRH agonists to prevent the tumor flare effect.

Antiandrogens can also be used as first-line hormone treatment in addition to orchiectomy or LHRH agonists. This is called combined androgen blockade .

If an antiandrogen starts losing effectiveness in a prostate cancer patient, interrupting treatment may temporarily stop cancer growth. We call this the antiandrogen withdrawal effect . Its cause has not yet been clarified.

Enzalutamide (Xtandi)

It is a new-generation antiandrogen treatment. Normally, when androgens bind their receptors, the receptor sends growth and division signals to the cell control center. Enzalutamide blocks this signal. Taken as a daily pill, it may benefit men with surgically resistant prostate cancer. In many drug studies, men were treated with an LHRH agonist. There is no clear information about its effect in men with testosterone levels without surgical intervention.

Possible side effects of hormone treatments

Orchiectomy, LHRH agonists and antagonists have similar side effects because testosterone levels fall.

These side effects include:

• Reduced or absent sexual desire
• Impotence
• Shrinkage of the penis and testicles
• Hot flashes that improve or disappear over time
• Breast tenderness and tissue enlargement
• Osteoporosis (bone thinning), potentially causing fractures
• Anemia (low red blood cell count)
• Mental weakness
• Loss of muscle mass
• Weight gain
• Fatigue
• High cholesterol
• Depression

Some studies have shown higher risks of high blood pressure, diabetes, stroke, heart attack and death from heart disease in men receiving hormone treatment. However, not all research has confirmed this.

Antiandrogens have similar side effects. The main difference from LHRH agonists, antagonists and orchiectomy is fewer sexual side effects. Used alone, sexual desire and erections generally persist. However, when given to men treated with LHRH agonists, diarrhea is the main side effect.

Abiraterone may cause joint or muscle pain, high blood pressure, fluid retention, hot flashes, stomach problems and diarrhea.

Enzalutamide may cause diarrhea, fatigue and worsening hot flashes. It also causes nervous system side effects, including dizziness and rarely stroke. Men taking it are prone to injuries from falls.

Most hormone treatment side effects can be prevented or treated.

For example, 

• Antidepressants and other drugs can often help hot flashes.
• Many drugs may prevent and treat osteoporosis.
• Depression can be treated with antidepressants or psychological counseling.
• Exercise may help reduce fatigue, weight gain, bone loss and muscle loss.