Endocrine Therapy in Prostate Cancer

Introduction

Cancer of the prostate ranks second in frequency among male malignancies, and its development is associated with androgen-dependent hormones, primarily testosterone. The prostate gland is a small organ situated beneath the urinary bladder and a major part of the male reproductive system since it is responsible for producing a fraction of the seminal fluid. Cancer of the prostate is either slow-growing or may become invasive and metastasize to different organs of the body. Depending on the stage, treatment of prostate cancer differs; however, one of the most effective ways to control the disease is hormone or endocrine therapy since it affects the potential of testosterone in growing cancer cells. In this article, we will explore the role of testosterone in prostate cancer, the mechanisms of prostate cancer hormone treatment, and possible side effects of hormone therapy.

What Are Male Sex Hormones and How Do They Affect Prostate Cancer?

Testosterone and dihydrotestosterone are examples of androgens in males which are involved in the development of male-related tissues. They also contribute to cell growth of the normal and the cancerous prostate cells. Androgens interact with androgen receptors in prostate tissues, whereby androgen binds to prostate cells and promotes the growth of the cells. This mechanism is critical to the advancement and progression of prostate cancer.

What Is Endocrine Therapy for Prostate Cancer?

Endocrine therapy for prostate cancer, or prostate cancer hormone treatment, involves the use of drugs specifically meant to counter the effects of male hormones – most particularly testosterone, which is known to stimulate the growth of prostate cancer cells. The therapy is also directed at reducing the level of, or inhibiting, the activity of, androgens, including testosterone, thereby halting the advance of the cancer or shrinking the tumor. This method is usually applied when prostate cancer has progressed to advanced stages or when surgery or radiation may not be applicable.

How Does Endocrine Therapy Work in Treating Prostate Cancer?

Endocrine therapy works by targeting the role of testosterone and other androgens in promoting the growth of prostate cancer cells. These hormones bind to androgen receptors on the cancer cells, stimulating growth. By reducing or blocking the production of testosterone, androgen deprivation therapy (ADT) essentially "starves" the cancer cells of the hormones they need to grow. The therapy can be used in various stages of prostate cancer, either alone or in combination with other treatments, depending on the severity and stage of the cancer.

How Is Endocrine Therapy Used in Prostate Cancer Treatment?

When the cancer is more aggressive, or the cancer cells are growing as a result of testosterone’s effects, endocrine therapy may be used in treating prostate cancer. It may be used in the following situations:

• Metastatic (spreading) carcinoma of the prostate that is confined to the prostatic gland or has spread locally and cannot be eradicated by surgical and/or other localized therapies.

• Other forms of treatment, such as radiation therapy, help reduce the size of prostate cancer tumors.

• In further treatment of a node-negative localized prostate cancer so as to reduce the chances of recurrence after surgery or radiotherapy.

• When prostate cancer emerges after initial treatment, emerged of when it has developed resistance to initial treatments.

What Are the Types of Endocrine Therapy for Prostate Cancer?

There are multiple subtypes of endocrine therapy used in the management of prostate cancer based on the phase in the hormone synthesis or the hormone’s effects that they address. These therapies can either reduce the amount of testosterone in the body or prevent it from acting on prostate cancer cells.

• Gonadotropin-Releasing Hormone Antagonist or Luteinizing Hormone: The main drugs include LHRH agonists that work by getting the body to stop producing testosterone. SERM (selective estrogen receptor modulator) does this by per-starting an impulse to the pituitary gland, which releases luteinizing hormone (LH) that triggers the increment of more testosterone in the testes. However, after using these drugs for some time, the body develops feedback, and the production of testosterone is lowered. The typical LHRH agonists are Leuprolide, Goserinine, and Triptorelin.

• LHRH Antagonists: LHRH antagonists are similar to LHRH agonists in that both cause the pituitary gland in the body not to release the hormone luteinizing hormone (LH). But they exert their action more vigorously, and do not elicit the initial rise in testosterone levels like LHRH agonist. They are prescribed for that purpose when prostate cancer has to be controlled with a rapid decrease in testosterone. LHRH antagonists are few and include Degarelix.

• Androgen Receptor Blockers: Androgen receptor blockers are drugs that inhibit testosterone and other androgens from residing on the androgen receptors in prostate cancer cells. By locking this binding, these drugs ensure that the hormones cannot facilitate cancer cell growth. This therapy is usually combined with other types of androgen deprivation therapy in order to achieve enhanced outcomes. Androgen receptor blockers include drugs such as Flutamide, Bicalutamide, and Nilutamide.

• Orchiectomy (Surgical Castration): Orchiectomy, also referred to as surgical castration, involves the removal of one or both testicles. Since the testicles contain the components of the testes where testosterone is produced in men, low testosterone levels resulted in this method leading to atrophy or non-development of prostate cancer cells. Even though it is a permanent solution, it may be suggested if other procedures are not possible or appropriate for the patient.

What Are the Side Effects of Endocrine Therapy?

Side effects of endocrine therapy include the following:

• Hot Flashes and Sweating – Rapid heat, excessive sweating.

• Fatigue – Tiredness, lack of energy.

• Mood Changes – Irritability, depression, anxiety.

• Weight Gain – Especially around the midsection.

• Bone Thinning – Risk of osteoporosis, fractures.

• Joint and Muscle Pain – Stiffness, discomfort.

• Memory Problems – Trouble concentrating, forgetfulness.

• Sexual Issues – Low sex drive, vaginal dryness (in women), erectile dysfunction (in men).

• Digestive Problems – Nausea, bloating, diarrhea, constipation.

• Increased Risk of Clot – Elevated risk of blood clot stroke.

• Heart Complications – Possible heightened risk of heart disease.

• Thinning of Hair – Diminished rate of hair growth, minor loss of hair.

Conclusion

Endocrine therapy for prostate cancer consists of the attempt to minimize the effects of testosterone on prostate cancer growth because of its stimulating effect on the tumor, with the help of such treatment as androgen deprivation therapy. While this approach can greatly minimize the prostate cancer progression rate, this kind of knowledge of the possibilities of side effects of prostate cancer hormone treatment is beneficial. Possible side effects may also include a reduced libido, problems with erection, hot flashes, and bone density issues. It is well known that hormone therapy has side effects this is a normal problem that can be alleviated with proper attention.