INTRODUCTION
Prostate cancer is a disease in which cancer develops in the prostate, a gland in the male reproductive system. Cancer occurs when cells of the prostate become abnormal and begin to multiply out of control. These cells may spread (metastasize) from the prostate to other parts of the body, especially the bones and lymph nodes. This cancer occurs only in men, as the prostate is exclusively of the male reproductive tract. Prostate cancer may cause pain, difficulty in urinating, erectile dysfunction and other symptoms. Prostate cancer is most often discovered by physical examination or by screening blood tests.
This year about 219,000 men will learn they have prostate cancer. It is the most frequently diagnosed cancer in American men, excluding skin cancers. One in every six men will receive a prostate cancer diagnosis at some time in their lives. Chances for successful treatment and survival are better than for many cancers. Overall, 99 percent of prostate cancer patients live at least five years after diagnosis. Ninety-two percent survive 10 years and 61 percent live 15 or more years. Even with these encouraging numbers, about 27,000 men will die of the disease this year. Prostate cancer represents the second leading cause of cancer deaths in American men.
Better detection methods enable earlier diagnosis and treatment. When caught before prostate cancer cells spread to other parts of the body, as it is for about 86 percent of men, nearly all men live at least five years. But when diagnosis is delayed until after the cancer migrates to the bone or other tissue, the five-year survival rate drops to 34 percent.
No one knows exactly why some men develop prostate cancer. Age is a prime risk factor. More than 70 percent of all patients are age 65 years or older at time of diagnosis. Prostate cancer occurs more frequently in African-American men than Caucasians and least frequently in Asian men. Having a brother or father with prostate cancer increases your chance of developing prostate cancer.
Remember statistics represent estimates based on thousands of cases. Individual risks and prognoses differ and should be discussed with your physician.
*Reference: American Cancer Society 2006, Cancer Facts and Figures
THE PROSTATE GLAND
The walnut-sized prostate is a gland in the reproductive area of a man's body. It produces some of the seminal fluid that protects and feeds sperm. This fluid is important to proper functioning of the male reproductive system. The prostate gland surrounds the upper part of the urethra, which is the tube though which urine travels from the bladder. The prostate is located below the bladder and in front of the rectum. Because of the gland's close proximity to the rectum, doctors can feel the contour of the prostate during a rectal exam.
SYMPTOMS
Prostate cancer symptoms frequently mimic those of benign prostate enlargement. Patients may experience urinary frequency, difficulty passing urine, or a slow or weak urine stream. Later on as the cancer becomes more advanced, patients may notice blood in the urine or difficulty getting an erection. Pain in the hips, spine or ribs commonly occurs if the cancer has spread to the bones. Other diseases can cause similar symptoms. Always discuss new symptoms with your doctor.
DIAGNOSIS
Depending on your age, your doctor may screen for prostate cancer. If screening tests indicate a problem, additional testing may be recommended. If you exhibit symptoms of prostate cancer or enlargement, the doctor will likely perform a physical exam, including a digital rectal exam, and order additional tests.
The diagnosis of prostate cancer can be confirmed only by a biopsy. During a biopsy, a urologist (a doctor who specializes in diseases of urinary and sex organs in men, and urinary organs in women) removes tissue samples, usually with a needle. This is generally done in the doctor's office with local anesthesia. Then a pathologist (a doctor who identifies diseases by studying tissues under a microscope) checks for cancer cells.
The most common tests performed for the detection of prostate cancer are:
PSA blood test - measures levels of PSA (prostate-specific antigen) in the blood. The prostate gland produces prostate-specific antigen, which is a small protein molecule. In men who do not have prostate cancer, this antigen is usually present at very low levels. The level of PSA may rise when a man has prostate cancer. This test has the ability to detect prostate cancer at very early stages.
Digital rectal exam - the doctor inserts a gloved finger into the rectum. Through the rectal wall, a doctor can feel the prostate and assess its texture and size.
If there is indication of prostate cancer, further tests are warranted:
TRUS (transrectal ultrasound) - a probe inserted into the rectum uses sound waves to "map" or "see" the prostate gland for possible suspicious areas.
Biopsy - provides the only definitive diagnosis for cancer. The doctor will insert small, thin needles through the rectal wall and into the prostate gland to obtain tissue samples. Ultrasound helps guide the physician. A pathologist will look at the samples under a microscope to check for cancer cells. The doctor may also remove tissue from lymph nodes near the prostate gland to check for spread of the cancer cells. This may occur during surgery to remove the prostate gland or during a special procedure if the patient chooses non-surgical treatment.
GLEASON SCORE
When doctors detect prostate cancer, they evaluate the cancer cells' aggressiveness on a scale called the Gleason score. The pathologist assigns a grade to the two most common cellular patterns on each tissue sample.
Grade 1: Cancer is well differentiated and looks quite similar to normal prostate tissue.
Grade 2: Cancer is still well differentiated but is arranged more loosely and more irregular in shape.
Grade 3: This is the most common grade of prostate cancer. Cancer is moderately differentiated, varying in size from small to large.
Grade 4: Cancer is poorly differentiated, unable to form separate units, highly irregular distorted shapes.
Grade 5: Cancer is undifferentiated and bears no resemblance to normal cells.
The combination of the two scores becomes the Gleason score, which ranges from two (2) to ten (10). The higher the score, the more aggressive the cancer and the more likely it will spread. The score may influence the recommendation for treatment.
STAGING
Staging of prostate cancer determines whether and how much the cancer has spread. Cancer staging plays an important role in treatment decisions and prognosis and is most commonly based on the TNM (Tumor, Nodes, Metastases) system.
Stage T1 - The tumor is confined to the prostate and was usually discovered after a PSA test and biopsy. The doctor cannot feel the tumor during a digital rectal exam.
Stage T2 - The tumor can be detected by the digital rectal exam or ultrasound. But it remains confined to the prostate gland.
Stage T3 - The cancer has spread to tissue next to the prostate gland or the seminal vesicles.
Stage T4 - The cancer has spread to tissue or organs near the prostate such as the bladder area, rectum or wall of the pelvis.
Stage N+ - The prostate cancer has spread to the pelvic lymph nodes.
Stage M+ - The prostate cancer has spread to other lymph nodes, organs or bone.
Once you have been diagnosed with prostate cancer, the doctor may order additional tests to determine if the cancer has spread outside of the prostate. These tests may include:
ProstaScint® Scan - ProstaScint is an imaging agent that can help locate and identify previously diagnosed prostate cancer that has spread to other areas within the body, such as the lymph nodes, adjacent tissue and bones. ProstaScint is a monoclonal (single clone) antibody that is combined with a small amount of radioactive material. As ProstaScint circulates throughout the body, it attaches to an antigen called PSMA (prostate specific membrane antigen), which is located on prostate cancer cells. Pictures are then taken with a special camera used in the nuclear medicine department. Click here for the ProstaScint Patient Instruction Guide.
Bone scan - may be ordered to assess whether cancer has spread to the bones. The patient receives an injection of a radioactive substance that localizes in areas of abnormal bone activity. If the scan detects a "hot spot" the doctor may biopsy the area to check for cancer cells.
CT scan (computed tomography) - is a non-invasive procedure that uses X-rays to create cross-sectional images of the body. Doctors may order it to look for enlarged lymph nodes in the pelvis or indications of cancer growing in other areas outside the pelvis. The test may include ingestion of a contrast agent to help outline internal structures.
MRI scan (magnetic resonance imaging) - uses radiowaves and magnets to provide detailed images. An MRI may indicate cancer has spread to the bladder, seminal vesicles or other nearby tissue.
TREATMENT OPTIONS
After diagnosing and staging, your doctor will discuss the most appropriate course of treatment for you. Treatment options vary depending on whether the cancer is localized or has spread, as well as your age, overall health and concerns about side effects. The most common types of treatment for prostate cancer are:
Surgery - removal of the prostate gland and surrounding tissue. Nerve-sparing operations aim to preserve nerve function needed to obtain an erection. This approach may be an option if the cancer has not spread to the nerves.
External beam radiation therapy - high doses of X-rays and particles such as electrons are used to kill cancer cells. The rays are directed at the cancer from a source outside the body. Treatment at a cancer center typically occurs five days per week for seven or eight weeks.
Brachytherapy or internal radiation therapy - small radioactive pellets are implanted into the prostate gland. Placing the "seeds" into the tumor maximizes the dose of radiation used to kill the cancer cells while minimizing the dose to the surrounding normal tissues, nerves and blood vessels.
Active Surveillance - this approach may be recommended if prostate cancer is not aggressive, is not causing any symptoms and is contained to the prostate gland. Because some prostate cancers can be slow growing, older men who have the disease may not need immediate treatment.
Cryotherapy - this treatment uses very cold gases to freeze and destroy prostate tissue. The doctor administers the therapy through needles and monitors the effects on images provided by transrectal ultrasound.
Hormone therapy - Most prostate cancers depend on male hormones, such as testosterone, to grow. Hormone therapy can shrink or slow the growth of prostate cancer. It is often used if prostate cancer recurs. It may also be ordered for men receiving radiation therapy. There are two types of hormone therapy. Drugs can decrease production of testosterone. Surgery to remove the testicles eliminates the main source of testosterone production.
Chemotherapy - uses anticancer drugs to kill cancer cells. These drugs may be ordered if prostate cancer has spread beyond the gland and hormone therapy does not work.
Immunotherapy - uses the body's immune system to fight cancer. This treatment stimulates or restores the ability of the immune system to fight infection and disease. It is also known as biological therapy, biotherapy or biological response modifier (BRM) therapy. Immunotherapy is still considered experimental.
Skeletal Targeted Radiopharmaceuticals - In cases of advanced disease, prostate cancer that has spread to the bones can result in significant pain. This pain is usually initially responsive to analgesic (pain killing) medications, however, as symptoms intensify sometimes other methods are required to treat the pain. One such method involves the injection of radioisotopes that seek out and bind to areas of the bone affected by cancer. These radioisotopes then provide a very high dose of radiation to the region, which can result in the relief of painful symptoms.
PROSTATE CANCER RECURRENCE
Recurrence occurs when cancer cells not eliminated during the initial treatment begin growing again. These cells usually are not visible to the eye or on imaging studies. They may have already migrated to other parts of the body. With time, the cells grow and cancer returns.
Patients whose original tumor was large or its cells aggressive are at greater risk of recurrence. Cancer cells found in the lymph nodes or other tissue at time of diagnosis also increase the chance of the cancer returning.
After initial treatment, prostate-specific antigen (PSA) levels should decline and remain at a low level. PSA levels generally become almost undetectable once the prostate has been removed, or are detectable but stable following radiation therapy. Your doctor will regularly check your PSA level.
A rising PSA level often gives the first indication that prostate cancer has returned. PSA levels can go up without causing any symptoms depending on how much and how quickly the PSA rises. Doctors often refer to a rising PSA, without other evidence of disease, as biochemical failure.
When prostate cancer comes back, it may grow in tissue adjacent to the prostate, such as the seminal vesicles or muscles that control urination. The disease also may appear in the lymph nodes or at distant sites, most typically the bone. This is called metastasis.
The doctor will perform a physical exam and order tests to locate where the prostate cancer cells are growing. Then he or she will recommend treatment to control the cancer and manage any symptoms that may develop.
The most common tests performed for assessing if the cancer has spread after PSA starts rising are:
ProstaScint® Scan - ProstaScint is an imaging agent that can help locate and identify previously diagnosed prostate cancer that has spread to other areas within the body, such as the lymph nodes. ProstaScint is a monoclonal antibody that is combined with a small amount of radioactive material. As ProstaScint circulates throughout the body, it attaches to an antigen called PSMA, which is located on prostate cancer cells. Pictures are then taken with a special camera used in the nuclear medicine department. Click here for the ProstaScint Patient Instruction Guide.
Bone scan - may be ordered to assess whether cancer has spread to the bones. The patient receives an injection of a radioactive substance that localizes in areas of abnormal bone activity. If the scan detects a "hot spot" it may indicate cancer has spread to the bone.
CT scan (computed tomography) - is a non-invasive procedure that uses X-rays to create cross-sectional images of the body. Doctors may order it to look for enlarged lymph nodes in the pelvis or indications of cancer growing in other areas outside the pelvis. The test may include administration of a contrast agent to help outline internal structures.
MRI scan (magnetic resonance imaging) - uses radiowaves and magnets to provide detailed images. An MRI may indicate cancer has spread to the bladder, seminal vesicles or other nearby tissue.
