Aid & Information
There has been great strides made in the treatment of prostate cancer in the past few years. The future looks bright for additional treatment using drugs.
Your body produces a variety of hormones, those that are produced in higher levels in men and are called androgens. Testosterone is the most well-known androgen. These androgens are made primarily in the testicles, but the adrenal glands located on top of the kidneys will also produce a small amount. Androgens are male sex hormones that fuel the growth of prostate cells, including prostate cancer cells. The basic idea behind androgen deprivation therapy is to block the production or effects of androgens on the body, thus, to slow or stop the growth of prostate cancer cells. Most prostate cancers eventually become "castration resistant," which means that they can continue to grow even when androgen levels in the body are extremely low or undetectable. Castration resistance may occur a few months or even years after hormone therapy has been started.
These drugs lower the amount of testosterone made by the testicles. Treatment with these drugs is sometimes called chemical castration because they lower androgen levels just as well as orchiectomy (surgical removal of the testicles). LHRH analogs are injected or placed as small implants under the skin. Depending on the drug used, they are given anywhere from once a month up to once a year. The LHRH analogs available in the United States include leuprolide (Lupron®, Eligard®), goserelin (Zoladex®), triptorelin (Trelstar®), and histrelin (Vantas®). After receiving the PSA levels will go up briefly before going down. This effect is called "flare"
LHRH antagonists work like LHRH agonists, but they reduce testosterone levels more quickly and do not cause tumor flare like the LHRH agonists do. Degarelix (Firmagon®) is used to treat advanced prostate cancer. It is given as a monthly injection under the skin and quickly reduces testosterone levels.
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.
Chemotherapy has two important properties: (1) Chemotherapy is systemic. This means that it works throughout the body and does not target a specific area (such as the prostate). (2) Chemotherapy is toxic. This means that it causes rapidly dividing cells to die. Therefore, chemotherapy works throughout the body to kill cancer cells. It also works throughout the body to kill rapidly dividing normal cells as well. Skin, hair follicle, gastrointestinal tract, and bone marrow cells are all rapidly dividing normal cells and are all, therefore, affected by chemotherapy. This explains why patients lose their hair, have gastrointestinal issues (such as nausea, vomiting, and diarrhea), and sometimes have low blood counts (blood cells are made in the bone marrow) while undergoing chemotherapy.
Patients who want to pursue chemotherapy as a prostate cancer treatment should know that chemotherapy is usually only used for patients who exhibit characteristics or advanced prostate cancer bone metastasis and when hormone therapy fails to the stop the growth of prostate cancer. The more quickly prostate cancer grows, the more likely the diseases will respond to chemotherapy treatment.
Common side effects of chemotherapy depend on the type of drug used, dosage and length of treatment. For prostate cancer patients, the most frequently used chemotherapy regimen is docetaxel and prednisone. The most common side effects of this regimen are fatigue, nausea and vomiting, diarrhea, hair loss, taste changes and a decrease in blood cell counts that result in an increased risk of infections. To minimize the side effects, chemotherapy drugs are carefully monitored according to the amount and number of times they are administered by your physician. Supportive medication is also given to further help offset the side effects caused by the drugs. For instance, new drugs to prevent nausea and vomiting can minimize these side effects. Most side effects disappear once chemotherapy is stopped.
Bisphosphonate drugs, such as clodronate or zoledronate, reduce bone disease when cancer has spread to the bone. Men who are treated with antiandrogen therapy or orchiectomy are at an increased risk of bone loss. In these men, bisphosphonate drugs lessen the risk of bone fracture (breaks). The use of bisphosphonate drugs to prevent or slow the growth of bone metastases is being studied in clinical trials.
Bisphosphonates can help manage bone problems when prostate cancer has spread to the bones. If cancer spreads to your bones, it may damage and weaken them. This can cause bone pain and increase your risk of broken bones.
Your bones are made of living tissue and are constantly changing. In healthy bones, cells are always breaking down and rebuilding bone tissue - this is called the bone cycle. When prostate cancer spreads to the bone, it upsets the careful balance between the breakdown of old bone and the building of new bone. This breakdown of bone allows the cancer grow larger by taking the space once occupied by the bone. More bone breaksdown, allowing the cancer to grow, and the cycle goes on and on.
Bisphosphonates prevent the breakdown of bone and encourage bone building in places where too much bone has been broken down. This can help to relieve pain. Bisphosphonates can also be used to treat a condition called hypercalcaemia which is high levels of calcium in the blood.
Zoledronic acid (Zometa®) is the bisphosphonate usually used to treat bone pain in men with advanced prostate cancer. Most men don't have problems taking zoledronic acid, but if you do, you might be given other bisphosphonates instead.
One of the rarest and most serious side effects of bisphosphonate treatment is known as osteonecrosis of the jaw, or ONJ. The American Cancer Society puts it best: "[In OMJ], patients complain of pain and doctors find that part of the jaw bone has died." Science is currently at a loss to explain why this occurs, but since the jaw bone can become infected and teeth can fall out, patients are urged to have a dental check-up prior to beginning bisphosphonate treatment.
Side effects vary from person to person. Some of the possible side effects are listed below.
Tell your doctor or nurse if you have this. They may recommend pain-relieving drugs such as paracetamol to help manage this.
Feeling sick (nausea) and being sick (vomiting)
You may feel or be sick after having bisphosphonates. This shouldn't last for more than a few days. If it does carry on, your doctor or nurse can give you anti-sickness medicines which will help.
Loss of appetite
You may feel less hungry after having treatment. This should improve in a few days, but it is important to drink plenty and eat healthily while you are having bisphosphonates.
Some men may experience a slight increase in joint, muscle or more bone pain when taking bisphosphonates. Pain-relieving drugs can help until the pain settles down, but you can stop treatment if it continues for more than a few days.
Low blood calcium and phosphate levels
Bisphosphonates can cause the levels of minerals such as calcium and phosphate in your blood to become too low. Your doctor or nurse will check this regularly and prescribe supplements if you need them.
Bisphosphonates can change how well your kidneys work. You will have regular tests to check this. These changes may not be serious, and your kidneys will return to normal if you stop taking bisphosphonates.
Red or sore eyes (conjunctivitis)
Your eyes may feel itchy, sore or dry. Your doctor or nurse can prescribe eye drops to help with this.
Rash or itching
You may notice a rash on your skin or feel quite itchy. This can be uncomfortable but should not last for more than a few days. Tell your doctor or nurse about this so they can prescribe medicine to help.
Stomach or bowel problems
You may feel stomach pain or notice changes in your bowel habits. For example, you may have loose and watery stools (diarrhoea).Or you may find it harder to pass stools and completely empty your bowels (constipation). This should not last more than a few days.
Risk of heart problems
Bisphosphonates may slightly increase your risk of heart problems, including a fast and irregular heartbeat and stroke. Talk to your doctor about this if you are worried about it, or if you have a history of heart problems.
Jaw problems (osteonecrosis of the jaw)
Osteonecrosis of the jaw is a rare side effect. It happens when the healthy bone in the jaw becomes damaged and dies. Keeping your teeth and mouth clean may help to lower your risk of getting osteonecrosis of the jaw. Ask your dentist if you have any questions about this.
This page lists cancer drugs approved by the Food and Drug Administration (FDA) for prostate cancer. The list includes generic names and brand names. The drug names link to NCI's Cancer Drug Information summaries. There may be drugs used in prostate cancer that are not listed here.