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Prostate cancer chemotherapy is usually used as salvage treatment during hormone refractory prostate cancer or for advanced prostate cancer with distant metastasis and has shown success in extending the life and quality of life in many patients.
Chemotherapy’s Role
in Prostate Cancer
Most cases of prostatic adenocarcinoma usually grow very slowly, meaning the cells divide at a rate that is similar to that of healthy cells. Chemotherapy, therefore, is usually not effective for early adenocarcinoma of the prostate. Why? Chemotherapeutic drugs are both toxic and systemic. Toxic because they damage cells so badly that upon division, the cell dies. Systemic because chemotherapy affects all the cells of the body as it circulates through the blood stream.
Like radiation therapies, chemotherapy does not destroy the entire body because only cells that divide soon after being treated will die. Unfortunately, chemotherapy cannot be focused to any particular area of the body. All quickly-dividing cells of the body therefore are affected, including, those in the hair follicles, skin, gastrointestinal tract, and bone marrow. The severe and sometimes dangerous side effects of chemotherapy drugs have often outweighed their benefits as an early prostate cancer treatment. However, for patients with advanced disease, chemotherapy can be beneficial in both extending the life and decreasing pain.
When is Prostate Cancer
Chemotherapy Used?
Prostate cancer chemotherapy is almost always a salvage therapy for advanced prostate cancer. Usually, when treatments like cryotherapy or prostate surgery fail, the next step is either another type of treatment or prostate cancer hormone therapy. Once the patient begins hormone therapy, the disease can be effectively controlled and even halted for a period of time. Hormone therapy will eventually fail, however, and the prostate cancer will continue to grow and spread. This is called hormone refractory prostate cancer and is commonly seen during the advanced stages of prostate cancer. The next step is usually chemotherapy.
Sometimes the disease will metastasize to the bones and is called advanced prostate cancer with bone metastasis. Bone metastasis can occur during hormone therapy treatment, but may not be apparent without a bone scan. Chemotherapy can be used to treat the cells in the bones that are now dividing malignantly. The pain associated with bone metastasis can be greatly relieved by the use of chemotherapy drugs. External radiation therapy is also sometimes used in conjunction with chemotherapy as a way to alleviate pain associated with advanced prostate cancer.
Recently, however, with the creation of new and more effective chemotherapy drugs, some doctors are putting their patients on chemotherapy drugs before these patients stop responding to hormone therapy. In some individuals, the earlier use of chemotherapy has been helpful in slowing the advancement of the disease. As of now, there are no studies that prove that starting chemotherapy earlier is better though some patients have benefited from an early uptake.
What are the Prostate Cancer Chemotherapy Drugs?
Some common chemotherapy drugs used as an advanced prostate cancer treatment include:
Mitozantrone (Novantrone) is an antineoplastic or anti-tumor antibiotic that is often used with the steroid prednisone for patients who are in pain due to bone metastasis.
Doxorubicin (Adriamycin) is an anti-tumor antibiotic, which damages the nuclei of cells and is derived from a bacterium Streptomyces Peuceticus.
Vinblastine (Velban) is an antineoplastic vinca alkaloid, which disrupts cell division and is derived from the Madagascar periwinkle.
Paclitaxel (Taxol) is a member of the taxane group, which works by locking the microtubules of cells and causing the cell to crumble during division.
Docetaxel (Taxotere) is another member of the taxane group, which originates in the bark of the Pacific Yew tree and is difficult to synthesize in a laboratory.
Estramustine Phosphate (Emcyt) is an alkylating agent, which damages the DNA of cells and lowers the testosterone produced by the body.
Etoposide (VP-16) works by inhibiting the process of mitosis in cancerous cells.
Carboplatin (Paraplatin) is an alkylating agent, which kills cancer cells by binding to DNA and interfering with the cell’s repair mechanism eventually leading to a cell’s death.
Vinorelbine (Navelbine) is an antineoplastic vinca alkaloid, which disrupts cell division and is derived from the Madagascar periwinkle. |
