Prostate cancer is the most common solid tumor in men in the United States, making up just over 13 percent of all new cancer diagnoses. An estimated 220,800 men will be diagnosed with prostate cancer in the United States in 2015, and more than 27,000 men are expected to die from prostate cancer in 2015.
About 14 percent of men can expect to be diagnosed with prostate cancer at some point during their lifetimes. In 2012, nearly 2.8 million men in the United States were estimated to be living with prostate cancer.
The majority of prostate cancers are localized to the prostate (the small gland that produces seminal fluid) at the time of diagnosis. Many of these cases can be cured with surgery or radiation, and many grow slowly enough that they may never require treatment of any kind. Some prostate cancers, however, are either more advanced at the time of diagnosis or advance despite attempts at curative therapy.
The use of hormone therapy in the treatment of prostate cancer was first tried in 1941. For decades, this was the only treatment available for patients whose cancer had spread beyond the prostate.
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Many prostate cancers, however, eventually stop responding to hormone therapy. Once a prostate cancer no longer responds to hormone therapy, it is referred to as advanced prostate cancer. For nearly six decades, no significant advances were made in the treatment options available for advanced prostate cancer, and the median survival of patients with this disease was between 12 and 18 months.
In 2004, chemotherapy was first demonstrated to improve the survival rates of patients with prostate cancer. Over the past decade, multiple new treatment options have been approved by the FDA for the treatment of advanced prostate cancer.
The recent rapid advances in the treatment of advanced prostate cancer make this a very exciting time for patients with this previously untreatable disease, as well as for the physicians who treat them. The excitement is tempered somewhat by the knowledge that advanced prostate cancer still remains incurable, and that these advances are occurring at the same time as pressure is being exerted to halt routine screening for prostate cancer.
There are several categories of advanced prostate cancer treatments that have been developed — including immunotherapy, advanced hormone therapies, specialized radiation therapy and chemotherapy. Each treatment option has been demonstrated to slow the progression of advanced prostate cancer and prolong patient survival by three to six months.
Sipuleucel-T (Provenge) is a prostate cancer-specific vaccine that takes advantage of the ability of the human immune system to recognize and attack foreign cells, including cancer cells. The vaccine is produced by drawing blood from a patient and then isolating the immune cells from the patient’s own blood. Those immune cells are exposed to specific markers that are found on prostate cancer cells.
The immune cells are then given back to the patient intravenously. Three treatments are administered at two-week intervals in the clinic. Most patients experience some mild flu-like symptoms (fever, headache, chills and the like) during the first 24 hours after the infusions. Severe side effects, though, are rare.
Prostate cancer cells typically depend on the presence of testosterone to be able to thrive. Standard hormone therapy takes advantage of this by stopping the body’s testosterone production.
Advanced prostate cancer develops when the prostate cancer cells learn to produce their own testosterone. Two of the new drugs for treating advanced prostate cancer are designed to stop the mutated prostate cancer cells from producing their own testosterone, causing a slowing of their growth and often a significant regression. These drugs, abiraterone (Zytiga) and enzalutamide (Xtandi), are oral medications. Side effects generally include some fatigue and weakness.
The single most common site of distant spread by prostate cancer (metastases) is the skeleton. Bone metastases can lead to pain and fractures. Radium-223 (Xofigo) is a radioactive element that localizes to prostate-cancer metastases in the bones. It is administered intravenously once a month for a total of six infusions. Prostate cancer that has spread to organs other than the skeleton cannot be treated with this therapy. The majority of patients who undergo this treatment experience significant improvement in pain rates. Most patients do not experience side effects with radium-223, though it can cause significant reduction in blood counts.
Chemotherapy can also be used to treat advanced prostate cancer. Docetaxel is the most commonly used chemotherapy drug for prostate cancer. Cabazitaxel is also used for treating prostate cancer. Both drugs are most commonly utilized only after treatment with some or all of the other advanced prostate cancer treatments, though there is now evidence that some patients may benefit from chemotherapy if metastases are present at the time they are diagnosed. Common side effects include fatigue, nausea and vomiting, low blood counts and loss of appetite.
Advancements over the past decade have led to many options for the treatment of this previously untreatable cancer. The speed with which advancements are being made as well as the number of therapies available has led to the development of specialized advanced prostate cancer clinics, which help doctors and patients work together to both prolong patients’ lives and improve their quality of life, too.
Dr. Todd Waldmann is a founding partner and current president of Idaho Urologic Institute. He is a board-certified urologist and urologic robotic surgeon. He also is a member of the American Urologic Association, the Ada County Medical Society and the Idaho Medical Association. Waldmann is a diplomate of the American Board of Urology. Learn more about Idaho Urologic Institute at idurology.com.