Chemotherapy for Prostate Cancer
Dear OncoLink "Ask The Experts,"
I have prostate cancer that has progressed on hormone therapy. My doctor wishes to start chemotherapy. I know many men with prostate cancer and I have never heard of them receiving chemotherapy. What can you tell me about chemotherapy for prostate cancer?
Carolyn Vachani RN, MSN, AOCN, OncoLink's Nurse Educator, responds:
Prostate cancer that has stopped responding to hormone therapy is called hormone refractory prostate cancer. Hormone therapy can be with an LHRH agonist ( Luteinizing Hormone Releasing Hormone Agonist), with or without an antiandrogen, or achieved through orchiectomy (removal of the testes). When these therapies stop working, doctors turn to "second line" agents, which include ketoconazole, corticosteroids (such as prednisone), or estrogens. In patients with prostate cancer that spreads despite these treatments, chemotherapy is considered. Because this treatment is used after other treatments have failed, only a small percentage of prostate cancer patients will ever need chemotherapy.
A chemotherapy regimen, including the drug docetaxel and prednisone, is considered the standard of care for hormone refractory prostate cancer. Two phase III clinical trials have led the way for this standard. Prior to these studies, mitoxantrone was considered the chemotherapy of choice. The first found docetaxel alone to have improved survival when compared to mitoxantrone and prednisone (18.9 months versus 16.5 months, respectively). The second trial (SWOG 9916) compared docetaxel plus estramustine to mitoxantrone plus prednisone, and found an improved survival in the docetaxel arm (18 months versus 15 months, respectively).
Studies are looking at combining docetaxel with other chemotherapy agents, such as estramustine, prednisone and thalidomide. Other agents that have shown activity against prostate cancer include: cyclophosphamide, vinblastine, vinorelbine, carboplatin, doxorubicin and etoposide. Various agents and combinations have been studied in clinical trials, but, to date, none have shown better outcomes than the docetaxel based regimens.
If the cancer progresses while on a chemotherapy regimen, the focus of care often turns to palliation. That is, providing treatment that will lessen the severity of symptoms such as pain and improve the quality of life while contending with a terminal illness. Palliative therapy can include docetaxel, paclitaxel, mitoxantrone, estramustine, prednisone, and radionuclide or radiation therapy.
Men with metastatic prostate cancer should also be considered candidates for a group of drugs called bisphosphonates. Prostate cancer frequently affects the bones, particularly in advanced cases. These drugs reduce the risk of bone fractures and improve bone density (strength) in prostate cancer patients.