What is prostate cancer?*
The prostate is a male sex gland that is about the size of a walnut. It produces a thick fluid that is a normal component of semen.
Prostate cancer is the most common cancer among men in the United States after non-melanoma skin cancer and the third leading cause of cancer-related deaths. However, because of widespread screening efforts, the majority of newly diagnosed prostate cancers are found early when they are still confined to the prostate gland, thus the number of prostate cancer-related deaths is decreasing.
How is prostate cancer detected?
Prostate cancer is usually detected with a combination of two tests: a prostate-specific antigen (PSA) test, in which the levels of a protein in the blood are assessed, and a digital rectal exam (DRE), in which the physician feels for any enlarged, irregular or firm areas on the prostate. Elevated PSA levels and/or an abnormal DRE will usually prompt the physician to perform a biopsy of the prostate.
A prostate biopsy is usually performed with local anesthesia in the physician’s office. Typically during this procedure, a transrectal ultrasound (TRUS) is used to visualize the prostate and help the physician guide the biopsy needle. The biopsy sample is then sent to a lab and assessed by a pathologist, who specializes in diagnosing diseases by examining tissue, blood and body fluids. If cancer is present in the sample, then further testing – such as a CT scan, MRI or PET-CT scan, or bone scans – may be recommended to determine the stage of cancer.
How is prostate cancer treated?
For patients with early-stage prostate cancer that is confined to the prostate itself, treatment options include surgery, external beam radiation therapy (EBRT), brachytherapy (LDR and HDR), CyberKnife® Robotic Radiosurgery
, hormonal therapy and watchful waiting. Each of these options is explained in detail below. Surgery
Prostate cancer surgery involves complete removal of the prostate and some of the adjacent tissues (radical prostatectomy). There are two types of surgery common for prostate cancer: open radical prostatectomy and laparoscopic prostatectomy. Open radical prostatectomy
There are two approaches to performing an open radical prostatectomy, a radical retropubic approach and a radical perineal approach. During a radical retropubic prostatectomy, the surgeon makes a long incision in the lower abdomen and removes the entire prostate with some surrounding tissues. Nerves in the surrounding tissues can be easily damaged during this procedure, resulting in impotence, so surgeons often use techniques to preserve the nerves around the prostate that control erections. Nerve-sparing techniques have been shown to decrease the incidence of impotence following radical prostatectomy, but there is still a high risk of impotence following surgery. The radical perineal approach involves the surgeon’s making an incision in the perineum, the skin between the testicles and the anus. Nerve-sparing techniques are more difficult in this approach.
A patient who undergoes open radical prostatectomy typically spends three to four days in the hospital and can expect to have a catheter remain in his urethra for three to four weeks to help with urination. Either surgical approach poses a significant risk of possible complications for patients, such as infection, bleeding, lengthy hospital stays, urinary side effects and impotence. In general, open prostatectomy is a highly effective modality for controlling prostate cancer, with long-term (10-15 years) overall survival ranging from as high as 97 percent. Urinary complications are common shortly after surgery, and in the long term, urinary incontinence may occur in 5-15 percent of patients and impotence has been reported to occur in 50-80 percent of patients.
Laparoscopic prostatectomy is becoming more popular because it is less invasive. During this procedure, surgeons make several small incisions in the abdomen. Instruments inserted through the small incisions are used to remove the prostate and surrounding tissues. There is little evidence that laparoscopic prostatectomy is superior to open surgery in its ability to control prostate cancer, but it does have a reduction in complications. Laparoscopic prostatectomy may be robot-assisted; in some reports of this method, complications have been reduced relative to non-robotic prostatectomy (urinary incontinence has been reported in 1-20 percent of patients, and impotence rates have ranged from 17 to 40 percent). A patient who undergoes laparoscopic prostatectomy typically is hospitalized for two to three days with a catheter in place in his urethra and has a shorter post-surgical recovery time compared to open surgery.
External beam radiation therapy
Radiation therapy is a non-invasive procedure that uses radiation to kill prostate cancer cells. Prior to treatment, CT and MRI images are taken to determine the exact location of the prostate and surrounding structures. A treatment plan is then created to deliver the radiation to the prostate and some of the surrounding tissue.
It is necessary to irradiate some of the surrounding healthy tissue during this treatment because there is a significant amount of variability in the day-to-day location of the prostate. The prostate can move inside the body from the effects of gas in the rectum and fluid in the bladder; this movement causes uncertainties in the prostate’s exact position. Each treatment session lasts several minutes. Treatments are typically delivered on an outpatient basis, five days a week, for seven to 10 weeks.
Published outcomes of prostate cancer treatment by external beam radiation therapy include long-term survival of as high as 91 percent. Patients may experience more rectal complications compared to surgery (10-20 percent of patients). Urinary toxicity has been reported in 10–15 percent of patients, and impotence has been reported in 20–64 percent of patients.
Brachytherapy is an invasive procedure that delivers radiation to the prostate from a source that is implanted within the prostate. There are two approaches to brachytherapy treatments: low dose rate (LDR) brachytherapy and high dose rate (HDR) brachytherapy.
In LDR brachytherapy, small radioactive “seeds” about the size of a grain of rice are placed in the prostate and remain there permanently. Typically, 40 to 100 seeds are placed in the prostate via a needle inserted through the skin. To relieve discomfort, the procedure is done using spinal anesthesia or general anesthesia. The procedure may require overnight hospitalization.
The seeds emit low-dose radiation to the prostate over several weeks or months, and the patient is radioactive while the radiation is being emitted by the seeds. LDR brachytherapy results in a high rate of long-term survival, ranging from 85 to 94 percent in published reports. Patients may experience low rates of urinary and rectal side effects (3-5 percent), and sexual dysfunction has been reported in 20-50 percent of patients. In very rare situations, the seeds have become dislodged from the prostate, entered the blood stream and migrated to other distant organs; however, this does not typically pose health complications.
HDR brachytherapy involves administration of high doses of radiation to the prostate over a short period of time. Typically, an HDR brachytherapy procedure involves insertion of 12 to 20 hollow needles containing catheters, which are inserted through the skin and into the prostate. Spinal anesthesia is usually given, and the procedure often requires overnight hospitalization. After the catheters are in place, a CT scan and/or an MRI is taken to confirm the exact location of the catheters, the prostate and surrounding tissues. A treatment plan is then created and a radioactive source is placed through the catheters to allow radiation to reach the prostate. The radioactive source remains at a location in the prostate for five to 15 minutes and is then removed. Often, the treatment occurs over several days and the catheters are removed after the last treatment.
Studies have shown that HDR brachytherapy results in excellent local control rates (89-98 percent in 3-6 years after treatment) with rates of urinary, rectal and sexual-function side effects that approximate those obtained with LDR brachytherapy. Nevertheless, this procedure can be painful and difficult for patients to undergo because of its invasiveness.
Radiosurgery, such as treatment with the CyberKnife Robotic Radiosurgery System, offers patients a different option for the treatment of prostate cancer. Because the prostate moves unpredictably in the body as air passes through the rectum and as the bladder empties and fills, other forms of radiation therapy can include irradiation of surrounding healthy tissue. The CyberKnife is able to overcome this challenge by continuously identifying the exact location of the prostate tumor throughout the course of the treatment, thus reducing the need to expose surrounding tissue to unnecessary irradiation. Treatments are usually painless and performed on an outpatient basis. Learn more about CyberKnife for prostate cancer treatment.
Male hormones, known as androgens, are produced normally by men; unfortunately, they help support the growth of prostate cancer cells. The goal of hormonal therapy is to decrease the amount of the specific hormones produced, in order to control the growth of the cancer cells. Hormonal therapy is usually prescribed in combination with other treatments, including external beam radiation therapy or brachytherapy, or before surgery to help shrink the size of the tumor. Side effects associated with hormonal therapy can include decreased libido, impotence, hot flashes, osteoporosis and breast tenderness.
Prostate cancer is often a slow-growing cancer. Physicians may recommend that a patient receive no immediate treatment, instead just closely monitoring the patient with periodic PSA testing and rectal exams. Some men, especially those who are older or who have other health problems, may never need prostate cancer treatments.
*Source material drawn from www.cyberknife.com. Please refer to that website for a complete listing of references used in the original information sections.
CyberKnife® is a registered trademark of Accuray Incorporated.