Prostate Cancer Chapter 12
Prostate cancer patients are likely to have a number of treatment options to choose from. If you have prostate cancer, you may feel pressured to make a decision quickly. But take the time to learn as much as you can about prostate cancer, your prognosis, and the treatments that are appropriate for your case. Talk to your doctor and, preferably, get a second opinion as well. Bear in mind that a surgeon may tend to recommend surgery and a radiation oncologist to recommend radiation therapy. Consider your own feelings about these treatments and their possible side effects.
Types of Prostate Cancer Treatment
Active surveillance is a relatively new approach to prostate treatment. It aims to identify men with early, low-risk prostate cancer who do not need immediate curative treatment, such as surgery, radiation, or cryotherapy. Such patients can potentially be spared the pain and side effects of aggressive treatment. Active surveillance delays curative treatment until a rapidly rising PSA rate, or other test, shows it is necessary.
Watchful waiting is a management alternative for men who are older and who have slow-growing cancers, and men who have physical conditions that don't allow them to undergo the rigors of surgery or radiation therapy. If they are without symptoms or their symptoms are mild, more radical treatment may well be unnecessary.
Watchful waiting includes regularly scheduled PSA and DRE tests to monitor the growth of the prostate cancer, as well as monitoring of symptoms. Should symptoms (such as urinary retention, kidney failure, bone metastasis, or pain) become acute, the treatment given will be palliative, such as hormone therapy, and not curative in intent. Doctors typically recommend that a patient receive a more aggressive form of treatment if he can expect to benefit from it for 10 years or more. For younger patients or those with fast-growing tumors, watchful waiting may not be an option.
Prostate surgery, termed prostatectomy, is the removal of the prostate gland. It is a curative approach and is used only if the cancer is locally confined. In a radical prostatectomy, the entire prostate gland and possibly the seminal vesicles and surrounding nerves and veins are removed. The part of the urethra that passes through the prostate's transition zone is removed as well, and its two ends reconnected.
There are three types of prostate surgery, classified by where the incision is made:
- Retropubic. The incision is made in the center of the lower abdomen and is about 3-4 inches (8-10 cm) long. Lymph nodes are commonly removed first in this type of surgery to see if cancer has spread to them. If it has, the procedure may be stopped and the prostate left in place. Nerve sparing is possible with retropubic surgery; that is, the surgeon will try not to injure the nerves in the course of the operation. This is important because nerve damage can result in impotence.
- Perineal.The incision is made in the perineum, between the anus and the testicles. Lymph nodes can't be removed in this type of surgery, but they can be removed in other ways if necessary. Nerve sparing is difficult with perineal surgery.
- Laparoscopic and robotic.A series of small incisions are made, rather than one large one. A laparoscope, a thin tube with a video camera at the end, is inserted into an incision to enable the surgeon to see inside the body, and the operation is performed using long surgical instruments. In the robotic form of this surgery, the surgeon maneuvers the instruments using robotic arms that are controlled from a separate console. Nerve sparing is possible with this approach. Advantages over retropubic surgery include less blood loss and pain, shorter hospital stays, and faster recovery time.
Radiation may be used as treatment for cancer that has not spread outside the prostate gland, or has spread only to nearby tissue. It may also be used if the cancer is not completely removed or recurs after surgery.
There are two forms of radiation therapy: external and internal (brachytherapy).
External Radiation Therapy
In external radiation therapy the goal is to irradiate a targeted area while avoiding surrounding tissues. Radiation damages a cell's DNA. If the irradiated cell divides before it can repair the damage, that cell will die. Because cancer cells divide more rapidly than healthy cells, healthy cells are better able to repair the damage done by the radiation.
Targeting a precise area is crucial to the success of radiation therapy. External prostate radiation therapy typically lasts 5-9 weeks.
There are three main different types of external radiation used for prostate therapy:
- Photon beam is the standard type of radiation therapy.
- Proton beam therapy is becoming more widely accepted.
- Neutron beam therapy is experimental.
External beam radiation is given in small doses over a long period of time. Typically, patients receive radiotherapy once a day, 5 days a week for 5-9 weeks. Receiving only a small dose of radiation every day helps to minimize the damage sustained by the healthy cells of the surrounding organs, and having weekends off helps the body to repair the damage done to it.
Internal Radiation Therapy
In internal radiation therapy, also called brachytherapy, radioactive seeds are implanted into the prostate. The implants deliver radiation in a higher dose than is used with external beams and over a longer period of time. The therapy is generally used in men with smaller or moderate-sized prostates with small and lower grade cancers.
There are two types of internal radiation therapy used to treat prostate cancer:
- Permanent low-dose radiation (LDR). In LDR, multiple radioactive seeds are left permanently inside the prostate to emit continuous low levels of radiation.
- Temporary high-dose radiation (HDR). HDR uses a single radioactive seed inserted into the prostate through a catheter. The placement of the seed varies according to the location of the cancer. The patient undergoes two or three treatments during the course of an overnight hospital stay. The seed is not left in place.
The male sex hormone, testosterone, fuels the growth and spread of prostate cancer. Hormone therapy seeks to stop the body from producing testosterone or to prevent the hormone from interacting with the prostate. In men with advanced prostate cancer, hormone therapy can both shrink the tumor and slow its growth. Hormone therapy may also be used to treat early-stage cancers or to shrink large tumors so that they can be removed by surgery or killed by radiation more easily. It can be used in combination with radiation therapy or surgery to delay the growth of any cancers that remain after treatment.
There are four main ways to administer hormone therapy for prostate cancer:
- Surgical: Orchiectomy is the surgical removal of the testicles, which produce testosterone.
- Chemical: LHRG agonists and LHRH antagonists block the messenger process in the brain that drives testosterone production in the testicles.
- Estrogen is mistaken by the hypothalamus for testosterone, which then stops production of a hormone that stimulates testosterone production. It is rarely used because it has been shown to cause cardiovascular problems.
- Anti-androgens prevent testosterone from interacting with the prostate gland.
- Combined androgen blockade uses both castration and anti-androgens to remove testosterone and block the prostate's ability to receive it.
Unfortunately, after several years prostate cancers may begin to thrive without testosterone, and hormone therapy becomes less effective. To prevent this from happening, intermittent therapy may be given. In it, hormone-therapy drugs are stopped when the patient's PSA numbers drop to a low level and stay there. The drugs are resumed if the PSA level rises again.
Chemotherapy for prostate cancer is generally used when hormone therapy has stopped being effective or when the patient has advanced cancer that has metastasized. It is not intended to cure the cancer, but can extend, and improve the quality of, life for many patients. The severe side effects of chemotherapy make it an inappropriate choice for early prostate cancers.
Chemotherapy is often used if the cancer has metastasized to the bone, because it can greatly relieve the patient's pain. It is also sometimes used in conjunction with radiation therapy for advanced cases to alleviate pain.
Recently, with the advent of new and more effective chemotherapy drugs, some doctors have started patients who are receiving hormone therapy on chemotherapy, before the hormone therapy ends. This seems, in some cases, to have slowed the progress of the cancer.
Some chemotherapy drugs are taken orally, others intravenously. Two or more drugs are sometimes taken simultaneously. Some of the drugs that are prescribed for prostate cancer are:
- Mitozantrone, an antineoplastic (antitumor) antibiotic often used with the steroid prednisone for painful bone metastasis o Vinblastine, an antineoplastic that disrupts cell division and is derived from the Madagascar periwinkle
- Doxorubicin, an antineoplastic antibiotic derived from the bacterium Streptomyces peuceticus
- Paclitaxel, a member of the taxane group, works by locking the microtubules of cells and causing the cell to crumble during division
- Docetaxel, like paclitaxel, is extracted from the bark of the rare Pacific Yew tree
Cryotherapy, also known as cryosurgery or cryoablation, is a relatively new form of minimally invasive surgery that destroys the prostate, and any cancer cells in it, by freezing them. It is only used to treat cancer that is still confined to the prostate. Because the results of cryotherapy haven't been studied over the long term, cryotherapy isn't used as often as radiation therapy for treatment of new cancers. It has, however, been found to be effective in treating cancer that is resistant to radiation treatment and so has recurred. Cryotherapy works by subjecting cells to subzero (-40 degrees Celsius) temperatures. Guided by ultrasound, the doctor inserts thin probes into the prostate through the perineum. Cold gases are then passed through the probes, creating ice balls in the prostate.
Side Effects of Prostate Cancer Therapy
Surgical risks are the same as those for any major surgery, including problems due to anesthesia, heart attack, stroke, blood clots in the legs, infection, and bleeding. Side effects include incontinence (lack of control in urination), impotence (inability to get an erection), sterility, lymphedema (swelling where lymph nodes have been removed), and shortening of penis.
Radiation Therapy: External
Bowel problems, bladder problems, incontinence, impotence, fatigue, and lymphedema.
Impotence, reduced sexual desire, hot flashes, breast tenderness and growth of breast tissue, loss of muscle mass, weight gain, constipation, diarrhea, headache, loss of appetite, trouble sleeping, osteoporosis, anemia, decreased mental acuity, fatigue, increased cholesterol, depression, increased risk of high blood pressure, diabetes, and heart attacks.
Loss of appetite, diarrhea, nausea, vomiting, loss of appetite, hair loss, mouth sores, increased risk of infection, bleeding and bruising after minor cuts or injuries, fatigue, headache, confusion, depression, ringing in the ears, vision problems, neuropathy.
Swelling in the genital area, blood in the urine, bowel problems, bladder problems, incontinence, impotence.
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