September 18, 2014 | by Hiu Chung So
For most prostate cancer patients, surgery or radiation therapy is the initial and primary treatment against the disease. But some patients can benefit from chemotherapy and hormone therapy too, especially if there are signs of a relapse or if the cancer has spread beyond the prostate gland.
Here, Cy Stein, M.D., Ph.D., City of Hope's Arthur & Rosalie Kaplan Chair in Medical Oncology, explains the role of drug therapy in treating prostate cancer, as well as recent and upcoming drug breakthroughs against the disease.
When is hormone therapy and/or chemotherapy an appropriate treatment for prostate cancer?
In many ways, when to start hormone and drug therapies for a prostate cancer patient is an art. That is because clinicians have to account for numerous factors, including the patient's age and health, the cancer stage and biology and the disease response to other therapies. For example, hormone therapy may be considered if a patient relapses following surgery and radiation therapy. Meanwhile, chemotherapy may be prescribed for a cancer that has metastasized to other organs or one that does not respond to other treatments.
Additionally, hormone therapy and chemotherapy protocols for prostate cancer are constantly evolving with new research findings. For example, a recent major study showed that combining hormone therapy with chemotherapy early on is significantly more effective against prostate cancer than hormone therapy alone, thus changing clinical guidelines and standards of care.
In short, both hormone and drug therapies can become an integral part of prostate cancer treatment by preventing relapse, slowing its growth and even driving it back into remission. But these treatments also require meticulous planning by medical oncologists in collaboration with others in the patient’s care team and in alignment with the latest evidence.
What are some recent drug breakthroughs against prostate cancer?
These past few years have been really exciting in terms of new drugs becoming available for prostate cancer patients.
Earlier this month, the Food and Drug Administration have approved enzalutamide (Xtandi) for use in a greater number of prostate cancer patients after a phase III clinical trial showed that it had significantly better outcomes compared to a placebo. This drug works by blocking receptors for the androgen hormone, which some prostate cancer cells use to fuel their growth.
Another recently approved drug is abiraterone (Zytiga), which works by blocking an androgen-making enzyme that is overexpressed in prostate cancer tissues.
What new developments are you looking forward to in the near future?
Currently there are quite a few ongoing clinical trials for prostate cancer; some are testing new drugs, some are testing new uses for existing drugs and some are comparing already-approved drugs. I am particularly interested in the upcoming results for studies comparing docetaxel (Taxotere) and cabazitaxel (Jevtana). Both are already approved to treat prostate cancer, but these subsequent trials can help us better plan a treatment regimen by showing us which patients and which cancers are more responsive to one drug versus the other. Thus, we can then get the maximum cancer-fighting effectiveness out of both drugs.
What are some side effects of prostate cancer drugs? How can they be managed?
The most common side effects include fatigue and reduced infection resistance due to lower red and white blood cell counts, respectively, as well as lymphedema (swelling of the limbs due to lymph fluid retention), nausea and hair loss. However, many of these side effects are temporary and can be addressed with other treatments, such as drugs that boost blood cell production.
What would you say to patients who are considering drug therapy to treat their prostate cancer?
Don't be afraid of it, most people will tolerate it just fine and it can have spectacular results for prolonging survival and improving quality of life.
Do you have a question for Cy Stein on prostate cancer treatments? If so, post below.
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