Chemotherapy for Prostate Cancer

Prostate cancer is the second leading cause of cancer deaths among men in the United States. Despite previous reports of chemotherapy's ineffectiveness in fighting prostate cancer, a number of recent medical studies are providing some hope with new cancer-fighting drugs. What is chemotherapy? What are some of the chemotherapeutic agents used to fight prostate cancer? The following information should help answer these questions.

What is the prostate?

The prostate, a part of the male reproductive system, is about the same size and shape as a walnut and weighs about an ounce. It is located below the bladder and in front of the rectum, and surrounds the urethra, the tube-like structure that carries urine from the bladder out through the penis. The main function of the prostate is to produce ejaculatory fluid.

Prostate cancer is a significant health-care problem in the United States due to its high incidence. It is the most common cancer in men affecting approximately 220,000 American men each year with approximately 29,000 of diagnosed men dying each year. Prostate cancer is different from most cancers in that a large percentage of men may have a "silent form" of this cancer — with no symptoms or spreading beyond the prostate gland. Sometimes this cancer can be small, slow growing and present limited risk to the patient. Clinically important prostate cancers can be defined as those that threaten the well-being or life span of a man.

What is chemotherapy?

Chemotherapy is the use of specific drugs that can destroy cancer cells. The drugs circulate throughout the body in the bloodstream and can kill any rapidly growing cells, including potentially non-cancerous ones. Chemotherapy drugs are carefully controlled in both dosage and frequency so that cancer cells are destroyed while the risk to healthy cells is minimized. Often, it is not the primary therapy for prostate cancer patients, but may be used when prostate cancer has spread outside of the prostate gland or in combination with other therapies.

Common side effects of chemotherapy depend on the type of drug used, dosage and length of treatment. The most common side effects are fatigue, nausea and vomiting, diarrhea, hair loss and increased susceptibility to infection. To minimize the side effects, chemotherapy drugs are carefully monitored according to the amount and number of times they are administered by your physician. Supportive medication is also given to further help offset the side effects caused by the drugs. For instance, new drugs to prevent nausea and vomiting can minimize these side effects. Most side effects disappear once chemotherapy is stopped.

How is chemotherapy administered?

The drugs used for chemotherapy can be administered directly into a vein or a muscle while others may be taken orally. Some of the drugs must be given in the doctor's office or clinic; others can be administered while the patient is at home. Hospitalization may be needed for certain types of chemotherapy that require special monitoring of both the treatment and its possible side effects.

While chemotherapy has not proven particularly effective against slow-growing prostate cancer cells, several promising new anticancer drugs are under study and are being added to surgery or radiation therapy for men with stage III (cancer has spread to surrounding tissue or seminal vesicles) prostate cancer. Chemotherapy is also being tried in conjunction with hormone therapy for men whose advanced cancers are no longer responsive to hormonal therapy alone.

There are many different chemotherapy drugs, each with their own strengths and weaknesses that are being tested for their effectiveness for prostate cancer. Some of these drugs include mitoxantrone, estramustine phosphate, etoposide, paclitaxel, docetaxel, doxorubicin and vinblastine. All of these agents are drugs that have encouraging anti-tumor effects in men with advanced prostate cancer.

In fact, there are now two clinical trials in which men with advanced prostate cancer progressing despite hormone therapy received mitoxantrone plus a glucocorticoid or the same dose of glucocoriticoid alone. In each of these trials, symptom improvement, reduction of pain medication and substantial PSA reduction were statistically more likely to occur in the group of men who received mitoxantrone.

A number of very interesting new combinations are being developed which appear to cause substantial PSA declines in more than 50 percent of men as well as symptomatic improvement in men with advanced disease. The three combinations being explored most actively are: docetaxel; docetaxal plus estramusine; and doxiorubicin plus ketoconazole alternating with vinblastine plus estramustine. A trial with docetaxel shows an improved survival rate. There are also new drugs being studied that interfere with cell growth - atrasentan and vitamin D analogues.

While considerable work remains to be done in developing truly effective chemotherapy for prostate cancer, there are new drugs available that can improve symptoms and the quality of life for men with advanced prostate cancer.

Frequently asked questions:

What are the advantages and disadvantages of chemotherapy? How do I know if it's right for me?

Chemotherapy provides an additional means of relieving the symptoms of advanced prostate cancer possibly by reducing pain and slowing tumor growth. However, because chemotherapy is a highly aggressive treatment with many side effects, it is important to discuss your treatment options with your doctor.

Some medicines may interfere with the effects of your chemotherapy drugs. To ensure that your treatment is the most effective that it can be, tell your doctor about any and all prescription and non-prescription medicines you are taking. Your doctor will tell you if you should stop taking any of these medicines before you start chemotherapy. After your treatments begin, check with your doctor before taking any new medicines or stopping the ones you already take.

Whether you can continue work, school and other activities depends on your treatment and how it affects you. For some treatments a hospital stay is needed, but most people are able to continue their activities during treatment. You might be able to schedule your treatments late in the day or before the weekend to minimize their interference with your activities.

Where can I get more information?

Prostate Specific Antigen (PSA).
Prostate Specific Antigen (PSA) (Zinio format).

AUA Guidelines Patient Guides: Prostate Cancer Awareness for Men

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