A Patient's Guide to Managing Hormone-Refractory Prostate Cancer  

Chapter 14.  Chemotherapy

The Basics

The modern use of chemical agents to treat cancer has been around for at least 60 years. Chemotherapy is used to treat cancers that have escaped the primary organ and established themselves in other tissues or organs. These are metastatic sites established by imaging techniques and are signs of disease progression.

Some cancers are not characterized by rapid growth. Prostate cancer is one of them. It may take 100 days or more for the cell population to double. The growth and division of normal and cancerous cells occur in a sequence of events called cell cycle that is divided in several phases. Chemotherapy agents are often classified based on whether or not their activity is cell cycle specific or nonspecific.

The cell cycle phases are:
G0 = Resting phase (non-proliferation of cells, dormant cells)
G1 = Pre DNA synthesis phase (12 hours to a few days)
S = DNA Synthesis phase (2 to 4 hours)
G2 = Post DNA synthesis phase (2 to 4 hours)
M = Mitosis or cell division phase (1 to 2 hours)

Chemotherapy drugs that exert their cytotoxic effect during a specific phase of the cell cycle are usually not effective on non-proliferating, dormant cells (G0). On the other hand, non-phase specific agents are theoretically more likely to be effective in a tumor population of dormant cells.

For a chemotherapy drug to be effective against a specific cancer, the drug must reach the cancer cells, penetrate the cells and remain there for a long enough period to cause damage to the cells. All this before drug resistance emerges and also on how well the patient is able to withstand the adverse effects of the treatment.

When to use chemotherapy for prostate cancer

The use of chemotherapy in earlier stages of advanced prostate cancer is not well defined or supported by clinical trials. Other cancers, such as breast cancer use such protocols based on survival benefits obtained in clinical trials. Such trials are in progress for prostate cancer patients at high risk of recurrence after a primary treatment.

After the failure of hormone suppression and/or secondary hormone suppression protocols, the most used systemic treatment is chemotherapy. It is important to note here that the current medical opinion is to continue controlling testosterone levels even when the patient has demonstrated resistance and is progressing while at castrate levels of testosterone.
Speaking broadly, there are two strategies for using chemotherapy. One newer approach is to use it early when the cancer is weak and the body is strong. With early use, it is felt that there is a stronger chance to attack both Androgen Independent and Androgen Dependent cells before the tumor burden is large and well established —without  devastating— the health of the patient. This strategy is used commonly in breast cancer, a cancer that is generally considered to be far ahead of prostate cancer treatment development due to multi-disciplinary exposure available to newly diagnosed breast cancer patients and not generally available to newly diagnosed prostate cancer men.
This is why for men with advanced prostate cancer, it is strongly suggested to involve a knowledgeable medical oncologist or urologic oncologist, who preferably specializes in prostate cancer, at an early point in their treatment.

Available chemotherapy agents for prostate cancer.*  Note some are available in an oral form or both oral and intravenous I-V).

• Docetaxel  (Taxotere)

• Paclitaxel  (Taxol)

• Estramustine  (Emcyt) (Oral)

• Etoposide  (VP-16) (Oral and I-V)

• Vinorelbine  (Navelbine)

• Vinblastine  (Velban)

• Mitoxantrone  (Novantrone)

• Doxorubicin  (Adriamycin)

• Epirubicin (Ellence)

• Suramin

• Cyclophosphamide (Cytoxan) (I-V, Oral)

• Carboplatin (Paraplatin)

• 5-FU (Fluoruracil)

• Xeloda (Capecitabine) (oral)

* Not all are U.S. FDA approved for PCa. Consult your doctor for insurance or Medicare coverage.

As with all drugs, these chemotherapeutic agents have cautions and warn of possible toxic effects:  reduction in bone marrow function, nausea and vomiting, mouth sores and ulcers, diarrhea, hair loss, skin changes (rash), allergic reactions (temperature, shivering, flushing, dizziness, headache, shortness of breath, anxiety), numbness or tingling in hands or feet, fluid retention, tiredness, aching joints and muscles.  In drug combinations, these possible effects are increased exponentially and are difficult to manage clinically.

Most of these side effects can be avoided or minimized by the use of bone marrow supporting drugs and other techniques and medications.

For a more complete discussion on chemotherapy treatments and help with side effects, visit the chemotherapy pages on the main website.

The J. of the American Medical Association has a patient page on Cancer Chemotherapy which has topics such as "Should I Take Chemotherapy or Not" -- which explains "Performance Status" and ""Questions to Ask Your Oncologist,"

Continue to Chapter 15



Ralph Valle 8/1/05, Update 8/1/08 HHansen