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Targeted Therapies for Prostate Cancer Tutorial

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Risks of Targeted Therapies

In This Section:

 

Overview

This tutorial has explained the evidence-based design of targeted therapies and has shown the benefits of taking a more precise aim at specific prostate cancer pathways and processes. However, like all new cancer treatments, targeted therapies are not without risks.

 

Hormone therapy risks

Hormone therapy may shrink or slow the growth of your cancer, but, unless it is used in combination with another therapy, it will not eliminate the cancer. Side effects of hormone therapy can include hot flashes, growth of breast tissue, weight gain, and impotence.

Shown on the left is an outline of a male body producing testosterone. On the right is an inset circle coming from the groin area showing a prostate tumor growing in the presence of testosterone. The screen text reads: Hormone therapy may shrink or slow the growth of your cancer, but, unless it is used in combination with another therapy, it will not eliminate the cancer.

And LHRH agonists may increase a man's risk of diabetes and certain cardiovascular diseases.

 

Therapeutic vaccine risks

Almost all of the patients who received the therapeutic vaccine Provenge® had some type of side effect; however, most of these were mild and transient. Common adverse reactions reported included chills, fatigue, fever, back pain, nausea, joint ache, and headache. About one-fourth of patients receiving Provenge® had serious adverse reactions, including stroke and some acute infusion reactions.

Shown on the right is an outline of a male body with a lymphatic system. A therapeutic vaccine has been administered. Screen title reads: Common adverse reactions. The bulleted list reads: Chills, fatigue, fever, back pain, nausea, joint ache, headache.

 

Taxane risks

Blood-related side effects seen in prostate cancer patients treated with taxanes include a decrease in the number of red blood cells (anemia), a decrease in the number of specialized infection-fighting white blood cells (neutropenia), a decrease in the number of white blood cells (leukopenia), and a low level of platelets in the blood (thrombocytopenia).

Other side effects seen include diarrhea, fatigue, nausea, vomiting, constipation, weakness (asthenia), and possible renal failure.

Shown are two healthcare providers talking to a male patient in a hospital setting. Screen text reads: Taxanes.

 

Other risks

The most common adverse reactions reported for the super-antiandrogen Zytiga were joint swelling or discomfort, low potassium level in the blood, fluid retention, muscle discomfort, hot flush, diarrhea, urinary tract infection, cough, high blood pressure, arrhythmia, frequent urination, urination at night, digestive problems and upper respiratory tract infection.

In addition, new types of drug resistance can develop in patients given targeted therapies. Sometimes resistance to therapy occurs because the target itself mutates, so the new therapy is unable to interact with its target as it did earlier.

Shown is a close-up of the membrane, cytoplasm and nucleus of a cancer cell. There are multiple receptors in the cell membrane. One of the receptors has a red starburst. A close-up view of this receptor is shown and is labeled 'Mutation.' Screen text reads: Drug Resistance in Targeted Therapies.

Other times, the resistance is indirect, in that the tumor finds a new pathway to achieve tumor growth in spite of the presence of a targeted therapy that is successfully blocking its assigned target.

Clinicians do not know whether using targeted therapies in combination with one another to treat prostate cancer will trigger new side effects. They do not know how long treatments should continue, nor do they know what combinations of targeted therapies will be most effective.

They also do not know if prostate cancer cells can establish alternate survival pathways and continue their growth even when a targeted therapy successfully destroys its target.

The clinical trials currently under way are trying to answer these questions, and others, as they arise.

Self Test

Questions

  1. What questions about targeted therapies for prostate cancer still remain unanswered and are being investigated in clinical research?
    1. Clinicians do not know how long treatments should continue.
    2. Clinicians do not know what combinations of targeted therapies will be most effective.
    3. Clinicians do not know whether combination therapies will trigger new side effects.
    4. All of the above.

Answers

  1. How does docetaxel target prostate cancer?
    1. Clinicians do not know how long treatments should continue. There is a better answer.
    2. Clinicians do not know what combinations of targeted therapies will be most effective. There is a better answer.
    3. Clinicians do not know whether combination therapies will trigger new side effects. There is a better answer.
    4. All of the above. Correct.