Prostate Cancer Treatment: Chemotherapy, Bone-Targeted and Immune Therapy

When do doctors use chemotherapy for prostate cancer?

Image of a man receiving chemotherapy drugs intravenously.
Image of a man receiving chemotherapy drugs intravenously.

Doctors may introduce chemotherapy and immune therapy if other measures fail to cure a case of prostate cancer. However, unlike with other forms of cancer, chemotherapy isn’t the first choice for early prostate cancer.

For example, prostate cancer can sometimes be halted by removing the prostate or using drugs to tamp down male hormone production. But if surgical or medical castration prove ineffectual at controlling the prostate cancer, doctors may start chemotherapy and/or immunotherapy.

Bone-targeted therapy helps a patient’s bone mass survive the chemotherapy assault and may help prevent prostate cancer metastasis to bone, the place where prostate cancers typically spread first.

The prostate is the gland in the male pelvis that wraps around the urethra and produces the fluid portion of semen. Men cannot produce offspring without a functioning prostate, and prostate cancer or some of its many types of treatments may cause impotence or incontinence.

What is chemotherapy for prostate cancer?

Chemotherapy or "chemo" for prostate cancer involves the use of medications, either in pill form or by injection into the veins, which can kill or at least slow the growth of metastatic prostate cancer cells. It does not presently have a role in the treatment of early stage prostate cancer except as part of clinical trials/research studies. The use of chemotherapy in metastatic prostate cancer is presently not a potentially curative treatment, but it can relieve symptoms of prostate cancer, and can prolong life. It is usually used in the setting of CRPC, castration- (medical or surgical) resistant prostate cancer.

Chemotherapy drugs work in many different ways. These drugs may damage the DNA of the cancer cells or disrupt the cells ability to divide (mitosis). These effects can cause cells to die. Not all prostate cancer cells may be sensitive to these drugs, but some may be. A tumor (a mass of cancer cells) will shrink if more cells are killed and removed than continue to grow and divide. As many normal tissues in the body also undergo the same patterns of growth and mitosis, these drugs have numerous side effects due to their effects on normal tissues.

Active chemotherapy drugs for the treatment of prostate cancer today include:

Although traditionally recommended for men with castrate-resistant prostate cancer, the NCCN recommended the use of docetaxel in combination with ADT and EBRT in men with high- and very-high-risk localized prostate cancer.

When these types of drugs are given to patients with prostate cancer they can help reduce pain and shrink tumors. Patients who respond to these drugs often live longer than those who do not respond.

What is immunotherapy/vaccine therapy for prostate cancer?

The immune system works by trying to very specifically target infections or to attack and kill cells which are either cancerous or are not our own. The immune system attempts to eliminate these invading problems using antibodies and cells called T-lymphocytes; in cases of cancer the immune system still struggles to control the problem for many reasons. The cancer seems often to either depress or overwhelm the immune system. Immune therapies (immunotherapy) attempt to boost the capability of our immune system.

Provenge (Sipuleucel-T) is a form of immunotherapy, a vaccine therapy, used to treat prostate cancer that has metastasized. It is appropriate in patients whose cancer is no longer responding to hormonal therapy but who are asymptomatic or minimally symptomatic. These patients may be showing a rise in PSA level after previous hormonal treatment has kept the PSA down for a long time.

Provenge therapy involves taking some of your own blood cells and growing them outside the body in the presence of a substance that is specific for prostate cancer. The cells are then given back to you by infusing them into the bloodstream. These cells can attack prostate cancer cells, and can help program other blood cells to do the same. Such treatment causes few side effects, including mild to moderate chills, fever, and headache, and can prolong survival by several months.

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What is bone-targeted therapy for prostate cancer?

Bone health is an essential component of prostate cancer treatment. Both the disease itself, as well as the treatment of the disease with androgen deprivation therapy, can have a significant impact on bone health. Several bone-targeted therapies have been approved.

Bisphosphonates

The bisphosphonates are a group of drugs used to treat several conditions people can get including osteopenia and osteoporosis. They also can lower elevated blood levels of calcium in people with cancer. They work by affecting cells in the bones called osteoclasts, which work to remove bone. These drugs encourage the death of the osteoclasts.

In prostate cancer they impact the course of skeletal-related events including reducing pain in the bones, and delaying the progression of bone metastases associated problems including the appearance of fractures (breaks in bones). While the bisphosphonates can affect the growth of prostate cells in the laboratory, they are presently not considered a targeted or direct-acting drug like a chemotherapy or hormonal treatment. They have also not been shown to prevent the appearance of bone metastases in prostate cancer patients. Nonetheless, they are an important part of the treatment of prostate cancer patients with bone metastases.

The most potent of the bisphosphonates is called zoledronic acid (Zometa). It is given intravenously. Its side effects are primarily reactions to the drug infusion. The dose of Zometa may need to be adjusted if the patient's blood tests show signs of deterioration in the function of the patient's kidneys. In addition, its use can predispose patients to serious dental conditions including what is called osteonecrosis of the jaw, which can result in breakdown of the bone of the jaw after dental extractions. It is advised that you see your dentist and have needed dental procedures performed prior to the start of a bisphosphonate.

Monoclonal antibody therapy

Denosumab (Xgeva) is a monoclonal antibody agent that inhibits the work of osteoclasts in a manner different from bisphosphonates. The medication inhibits a protein that tells the osteoclasts to remove bone. This drug is useful as a treatment for all of the conditions for which bisphosphonates are used. Given as an injection under the skin at intervals, it has a better side effect profile than the bisphosphonates. It does not require dose adjustments if kidney function deteriorates. It can still cause osteonecrosis of the jaw to occur. It is considered an important new drug in the treatment of bone metastases in prostate cancer patients. In some studies, it appears to be more effective than Zometa in delaying the initial onset of skeletal-related events in patients with bone metastases.

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Medically Reviewed on 1/9/2020
References
Ahlering, T., et al. "Unintended consequences of decreased PSA-based prostate cancer screening." World J Urol 37.3 March 2019: 489-496.

American Cancer Society (ACS). <http://www.cancer.org/cancer/prostatecancer/index>.

American Urological Association. "Clinically Localized Prostate Cancer: AUA/ASTRO/SUO Guideline." 2017. <http://www.auanet.org/guidelines/clinically-localized-prostate-cancer-new-(aua/astro/suo-guideline-2017)>.

Byrd, E.S., et al. AJCC Cancer Staging Manual, 7th Ed. New York, NY: Springer, 2009.

The James Buchanan Brady Urological Institute. Johns Hopkins Medicine.

Lu-Yao, G.L., P.C. Albertson, D.F. Moore, et al. "Fifteen-year outcomes following conservative management among men aged 65 years or older with localized prostate cancer." Eur Urol 68.5 (2015): 805-811.

Mottet, Nicolas, et al. "Updated Guidelines for Metastatic Hormone-Sensitive Prostate Cancer: Abiraterone Acetate Combined With Castration Is Another Standard." European Urology 73 (2018): 316-321.

National Comprehensive Cancer Network

"Prostate Cancer." Memorial Sloan Kettering Cancer Center.
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