Health Encyclopedia - Diseases and Conditions
Prostate Cancer
Definition of
Prostate Cancer
Article updated and reviewed by Larry A. Weinrauch, MD, Assistant Professor of Medicine, Harvard Medical School. Editorial review provided by VeriMed Healthcare Network on June 1, 2005.
The prostate is one of the male sex glands, located just below the bladder and in front of the rectum. The normal prostate is about the size of a walnut and it surrounds part of the urethra (the tube that carries urine from the bladder to the outside of the body). The prostate makes fluid that becomes part of the semen (the fluid that contains sperm). Cancer is a disease characterized by the uncontrolled growth, called a tumor, of abnormal cells. Prostate cancer is any type of malignant (cancerous) growth in the prostate.
In the U.S., prostate cancer is the most common cancer and the second leading cause of cancer deaths in men.
Causes and Risk Factors of
Prostate Cancer
The most common risk factors include:
- being over 55 years of age
- a family history of prostate cancer
- being African-American
Other possible risk factors include:
Symptoms of
Prostate Cancer
There are no symptoms in the earliest stages of prostate cancer. When symptoms do occur, they may include the following:
- the need to urinate frequently, especially at night
- needing to strain when urinating
- difficulty in starting urination or holding back urine
- the inability to urinate
- a weak or interrupted flow of urine
- painful or burning urination
- blood in the urine
- painful ejaculation
- continuing pain in the lower back, hips or upper thighs
Many of these symptoms are common to non-cancerous prostate conditions, including prostatitis (inflammation of the prostate), prostate stones, infection and BPH. It is important to have any of these symptoms checked by a doctor to find the problem.
Diagnosis of
Prostate Cancer
To find the cause of symptoms, the doctor will take a full medical history, a complete physical examination including a digital rectal examination and perform laboratory and diagnostic testing. The doctor will insert a gloved and lubricated finger into the rectum and feel the prostate to check for hard or lumpy areas. The doctor will also order a blood test, called a prostate-specific antigen (PSA) test.
Prostate-specific antigen is a protein secreted by the prostate. In men with enlargement or infection of the prostate or prostate cancer, the protein leaks into the circulatory system, thereby increasing the level of PSA in the blood. This test can be falsely elevated if drawn after the digital rectal exam, and may be affected by the medicine Proscar (taken for benign prostate enlargement. If the initial reading is elevated a repeat test is usually done in three to four months.
In order to confirm the diagnosis, the doctor will follow up an elevated PSA or positive digital rectal exam with more definitive testing. Some doctors request a transrectal ultrasonography (TRUS) be performed. In this procedure, sound waves are sent out by a probe inserted into the rectum. The waves bounce off the prostate and a computer uses the echoes to create a picture called a sonogram. TRUS helps the doctor map uneven areas of firmness in the prostate, which assists in the decision to do a biopsy.
There are two types of biopsies performed for the diagnosis of prostate cancer. The first is called a fine needle aspiration (or FNA) - a fine needle is inserted through the rectum or through the space between the scrotum and the anus, to withdraw cells from the suspicious area. The second is called a sextant biopsy - a needle is used to remove six cores of tissue from various sections of the prostate.
If prostate cancer is diagnosed, other tests, such as computerized tomography, lymph node biopsies, and bone scans, are used to determine if tumors have spread beyond the prostate.
When prostate cancer is diagnosed, the doctor will determine at what stage (phase or progression) the cancer is. The following gross staging system is used:
Stage A: Prostate cancer at this stage cannot be felt and causes no symptoms. It is only in the prostate and usually found accidentally when other prostatic surgery is performed.
Stage B: Prostate cancer at this stage is felt during a rectal examination and confirmed during a biopsy because of an elevated PSA level. Cancer is located in the prostate only.
Stage C: Cancer cells have spread outside the prostate to the tissues surrounding the prostate.
Stage D: Cancer cells have spread to lymph nodes or organs and tissues far away from the prostate.
In addition, when cells are looked at under a microscope, pathologists can determine a grade of aggressiveness of the cancer. Tumor growth is microscopically staged by the Gleason system - the tumor appearance under a microscope distinguishes its grade. The grades of tumors are from two to 10. A grade 2 tumor appears as clumped together cancer cells with well defined edges and is less likely to grow rapidly. A higher-grade tumor is dispersed with uneven edges that are prone to spread rapidly. However, after taking into account the tumor stage, the tumor grade, the man's age, and the man's overall health, some doctors would recommend other treatment methods.
Treatment of
Prostate Cancer
There are three methods of management -watchful waiting, local and systemic therapy. If the cancer is located in the prostate gland and considered slow growing, some doctors may recommend a conservative approach of "watchful waiting." During this time, the patient will receive no treatment, but the doctor will closely monitor the size and growth of the tumor and regularly test for elevated PSA levels.
Local treatments are used to remove, destroy, or control the cancer cells in a specific area. Surgery and radiation therapies are local treatments. Systemic treatments are used to destroy or control cancer cells all over the body. Hormone therapy is a systemic treatment.
Local treatments
Surgery
TURP (transurethral resection of the prostate): is a procedure in which the cancer is cut from the prostate using a tool with a small wire loop on the end that is placed into the prostate through the urethra. This operation is sometimes done to relieve symptoms caused by the tumor before other treatment, or in men who cannot have a radial prostatectomy because of age or other medical problems.
Radical prostatectomy: the removal of the prostate and some of the tissue around it. There are three approaches: (i) perineal prostatectomy, which is done by cutting into the space between the scrotum and the anus and removing the prostate, (ii) suprapubic or retropubic prostatectomy, which is done by cutting into the lower abdomen and removing the prostate, and (iii) more recently, some surgeons have become adept at removing the prostate through a laparascope. The doctor may take out the lymph nodes in the pelvis (a pelvic lymph node dissection) to see if they contain cancer. Radical prostatectomy has become more acceptable with the development of a nerve-sparing technique. The "nerve-sparing" technique is a radical prostatectomy that removes the prostate but leaves one or both of the nerve bundles on either side of the prostate intact so the patient has a chance of potency after surgery. Not everyone qualifies for nerve-sparing surgery, and it should be done only when it seems likely that the cancer does not lie close to the nerve bundles.
Radiation Therapy
External beam therapy is the use of high-energy x-rays to kill cancer cells and shrink tumors. Using a machine called a linear accelerator, radiation is passed through the diseased tissue by means of x-rays.
Seed implantation therapy is the placement of radioisotopes directly into the cancerous prostate, where they emit low-level radiation for about a year. With the help of a transrectal ultrasound and a computerized CT scan, doctors are able to view the precise size and shape of the prostate on a video monitor and guide needles containing the seeds with pinpoint accuracy into the cancerous part of the gland. Two different isotopes are used in prostate implants; Iodine-125 is generally used to treat slow-growing tumors, while palladium-103 is used for faster-growing cancers.
A variant on seed implantation is called high-dose-rate radiation. In this technique, a highly radioactive seed is attached to a wire that is momentarily inserted into the man's prostate through a number of hollow tubes.
There has been recent interest in the use of other minimally invasive techniques to treat prostate cancer and these include cryotherpy and focused ultrasound. Randomized trials are now underway utilizing these treatments to determine if they are effective.
Systemic treatments
Hormone therapy is the use of hormones to stop cancer cells from growing. One form of hormone therapy is called an orchiectomy (the surgical procedure for removal of one or both testes). After removing the testicles, the main source of male hormones is gone. Without these hormones, the growth of the prostate cells slows. In another form of hormone therapy, men are given estrogen, a female hormone, or luteinizing hormone-releasing hormone (LHRH), a laboratory made hormone. Both these drugs stop the testicles from producing testosterone. There is now data to demonstrate that as little as six months of hormonal therapy confers a survival benefit for those undergoing radiation therapy.
Chemotherapy is often used successfully in patients who are not responding to hormonal therapy resulting in better survival rates. Some novel immunotherapies (therapies that stimulate the immune system again abnormal cells) are also now in trials and include anticancer vaccines.
Staging Treatments
The fact that there are many different treatments for patients with prostate cancer often concerns patients. Physicians and surgeons are excited to have more tools to fight the disease then doctors of years ago. They have learned that in patients who are older, with less aggressive cancers with cells only in the prostate, “watchful waiting” has less risk than any aggressive measure.
Fortunately, early detection and technology have evolved to the point that an increasing number of men have more than one treatment option. Stage A cancers are sometimes found at the time of prostate removal for apparently benign disease. In such cases, since the gland has been removed, the cancer is only microscopic, or not considered aggressive by the pathologist, and further therapy may not be indicated. Other stage A cancers may warrant surgery, external or internal radiation, or consideration for trials of newer, sometimes experimental therapies (such as use of heat and cold, or focused ultrasound to destroy the tumor).
For men with Stage B or C cancers, surgery or radiation are available; different options can be discussed depending upon the patient’s age and other medical or surgical problems. These local therapies have similar risks of urinary incontinence (leakage), impotence (inadequate erectile function), or problems with ejaculation. Radiation avoids the risks of anesthesia, but may result in more colorectal problems. Hormonal therapy will often be offered for its survival benefit especially in patients choosing radiation therapy.
For men with Stage D cancer, hormonal therapy will generally be offered initially with each of the other types of therapy brought into play as they are needed.
What Questions To Ask Your Doctor About
Prostate Cancer
What tests are going to be done for an accurate diagnosis?
Has the cancer spread to any other areas?
What stage of prostate cancer is it?
What type of treatment do you recommend?
What are the risks from the medicines, from radiation, and from surgery?
If the medication (as in chemotherapy) is prescribed, what are the side effects?
What is the survival rate with or without therapy?
Would there be a benefit from taking part in a clinical trial?
What effects will this condition have on sexual activity? On urinary continence?
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