Treating Advanced Prostate Cancer
If cancer has spread to another location in the body, it’s called metastatic cancer. The standard treatment for metastatic prostate cancer is hormone therapy. Generally, prostate cancer will develop the ability to grow without using male sex hormones. This is called castrationresistant prostate cancer.
People with this diagnosis are encouraged to talk with doctors who are experienced in treating this stage of cancer, because there can be different opinions about the best treatment plan. Seek a second opinion before starting treatment so you are comfortable with the treatment plan chosen. This discussion may include clinical trials. Although there is no cure for advanced prostate cancer, it is often treatable. Many men outlive their prostate cancer, even those with advanced disease. Often, the prostate cancer grows slowly, and there are now effective treatment options that extend life even further.
Your healthcare team may recommend a treatment plan that includes vaccine therapy with sipuleucel-T (Provenge®), chemotherapy with docetaxel, or clinical trials. If you have pain, radiation therapy may also be recommended.
Seek a second opinion before starting treatment so you are comfortable with the treatment plan chosen.
Sipuleucel-T (Provenge) is a form of immunotherapy which is designed to boost the body’s natural defenses to fight the cancer. It uses materials made either by the body or in a laboratory to bolster, target, or restore immune system function.
In 2010, the FDA approved sipuleucel-T for men with castration-resistant metastatic prostate cancer with few or no symptoms, because in research studies it increased survival by about four months compared to no treatment. Sipuleucel-T is adapted for each individual. Before treatment, blood is removed from the person in a process called leukapheresis. Special immune cells are separated from his blood, modified in the laboratory, and then put back in the person receiving treatment. At this point, his immune system may recognize and kill the prostate cancer cells. Because this treatment is tailored for each person, it may not be available in all areas.
Chemotherapy is the use of drugs to kill cancer cells, usually by stopping the cancer cells’ ability to grow and divide. Systemic chemotherapy is delivered through the bloodstream to reach cancer cells throughout the body. A chemotherapy regimen usually consists of a specific number of cycles given over a set period of time. Someone may receive one drug at a time or combinations of different drugs at the same time.
Chemotherapy for prostate cancer is given intravenously, and it may help people with advanced or hormone-refractory prostate cancer. There is no standard chemotherapy for prostate cancer, but clinical trials are exploring chemotherapy for advanced prostate cancer. The most popular, current approach is the use of a drug called docetaxel given with a steroid called prednisone. This combination has been shown to help men with advanced prostate cancer live longer than another chemotherapy, mitoxantrone (Novantrone®), which is most useful for controlling prostate cancer symptoms.
The FDA has approved the drugs mitoxantrone, docetaxel, and cabazitaxel (Jevtana®) for use in men with prostate cancer that is resistant to hormone therapy. Cabazitaxel is similar to docetaxel, but research studies have shown that it can be effective for prostate cancer that is resistant to docetaxel. The side effects are similar to docetaxel and include low white blood cell counts, increased risk of infections, allergic reactions, nausea, vomiting, diarrhea, and kidney and liver problems.
Estramustine (Emcyt®), another FDA-approved drug, is being used much less often because of newer drugs that can prolong life and because of its side effects, which include an increased risk of blood clots. Many new medications for prostate cancer are in development and may be available in clinical trials. The side effects of chemotherapy depend on the individual and the dose used, but they can include fatigue, risk of infection, nausea and vomiting, loss of appetite, and diarrhea. These side effects usually go away once treatment is finished.
The medications used to treat cancer are continually being evaluated. Talking with your doctor is often the best way to learn about the medications prescribed for you, their purpose, and their potential side effects or interactions with other medications.
Some types of hormone therapy may be used to treat advanced cancer.
Because prostate cancer growth is driven by male sex hormones, called androgens, lowering levels of these hormones can help slow the growth of the cancer. Hormone treatment is also called androgen ablation or androgendeprivation therapy. The most common androgen is testosterone. Testosterone levels in the body can be lowered either surgically, with surgical castration (removal of the testicles), or with drugs that turn off the function of the testicles.
Hormone therapy is used to treat prostate cancer that has continued to grow after surgery and radiation therapy, or if it has spread throughout the body when diagnosed. More recently, hormone therapy has also been used with radiation therapy for men with a cancer that is more likely to recur. For some men, hormone therapy will be used first to shrink a tumor before radiation therapy or surgery. In some men with prostate cancer that has spread locally, called locally advanced prostate cancer, hormone therapy is given before, during, and after radiation therapy for three years. Hormone therapy is also an option for men who have prostate cancer that has spread to the lymph nodes (found after radical prostatectomy) as adjuvant therapy (treatment that is given after the first treatment). It may also be given for up to three years for men with intermediate-risk or high-risk cancer.
It is important to have open and honest conversations with your doctor and healthcare team.
Traditionally, hormone therapy was used until it stopped controlling the cancer. Then the cancer was called hormone refractory (meaning that the hormone therapy has stopped working), and other treatment options were considered. Recently, researchers have begun studying intermittent hormone therapy, which is hormone therapy that is given for certain periods and then stopped temporarily according to a schedule. Giving hormones in this way appears to lower the symptoms of this therapy. In addition, intermittent hormone therapy may possibly maintain hormone responsiveness for a longer time than standard (continuous) hormone treatment; this approach is currently being tested in clinical trials.
One important side effect of hormone therapy is the risk of developing metabolic syndrome. Metabolic syndrome is a set of conditions, such as high levels of blood cholesterol and high blood pressure that increases a person’s risk of heart disease, stroke, and diabetes. Currently, it is not certain how often this happens or exactly why it happens, but it is quite clear that men who receive a surgical or medical castration (even a temporary medical castration) with hormone therapy have an increased risk of developing metabolic syndrome. The risks and benefits of castration should be carefully discussed with your doctor. For men with metastatic prostate cancer, especially if it is advanced and causing symptoms, most doctors believe that the benefits of castration far outweigh the risks of metabolic syndrome.
In addition to treatment to slow, stop, or eliminate the cancer (also called disease-directed treatment), an important part of cancer care is relieving a person’s symptoms and side effects. It includes supporting the patient with his or her physical, emotional, and social needs, an approach called palliative or supportive care. People often receive disease-directed therapy and treatment to ease symptoms at the same time.
If disease-directed treatment is not successful, this may also be called resistant or advanced cancer. This diagnosis is stressful, and it may be difficult to discuss. However, it is important to have open and honest conversations with your doctor and healthcare team to express your feelings, preferences, and concerns. The healthcare team is there to help, and many team members have special skills, experience, and knowledge to support people with cancer and their families.
A few drugs can help treat the symptoms of advanced cancer to enhance the quality of the person’s life.
Chemotherapy is most commonly used for men with advanced, hormone-refractory prostate cancer. It can be effective in relieving symptoms, such as pain, weight loss, and fatigue, and may prolong life for some people.
Strontium and samarium
Given by injection, these radioactive substances are absorbed near the area of bone pain. The radiation that is released helps relieve the pain, probably by causing the tumor in the bone to shrink.
Given by injection, zoledronic acid reduces the level of calcium in the blood and causes fewer bone complications, such as pain, fracture, and need for surgery, from metastases. A high calcium level is called hypercalcemia and is sometimes found in men with advanced prostate cancer.
Denosumab (Prolia®, Xgeva®)
Recent research has looked at the use of denosumab to help slow the damage to bone from metastases and reduce bone side effects for men with castration-resistant prostate cancer. Results indicate that denosumab may be more effective at protecting the bones than zoledronic acid.
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Reprinted with permission from www.cancer.net. ©2012 American Society of Clinical Oncology. All Rights Reserved.
This article was originally published in Coping® with Cancer magazine, January/February 2012.