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Prostate Cancer
What is it?
The prostate is a walnut-sized gland found only in men. It is located just below the bladder and in front of the rectum where it can be felt during a rectal examination. The prostate gland produces some of the fluid that carries sperm. The urethra, the tube that carries urine and semen out of the body through the penis, runs through the prostate. The prostate gland may be a source of many health problems for men, including prostate cancer. Prostate cancer is often devastating to men, not only because of the effect on their health, but also because the treatments can result in sexual dysfunction and bladder control problems.
For American men, prostate cancer is the most common cancer and the second-leading cause of cancer death. The National Cancer Institute states that there have been nearly 220,000 new cases of prostate cancer reported as of November 2007, and 27,050 men have died. One out of every six men will be diagnosed with prostate cancer sometime during his life, and one of every 34 men with the disease will die as a result of the spread of prostate cancer cells to other parts of the body.
One test doctors can perform to help determine if an individual is at risk for prostate cancer is a prostate specific antigen (PSA) test. PSA is a protein made by the prostate that is elevated in patients with prostate diseases. The PSA test is regarded as superior to a rectal examination because early-stage prostate cancer (see the classification system discussed below) cannot be detected by a rectal exam.
An elevated PSA can indicate a small, early-stage prostate cancer, but it can also indicate the presence of benign prostatic hyperplasia (BPH)?an unharmful condition where the prostate is enlarged. Therefore, it is important to understand that an elevated PSA does not necessarily indicate cancer. Despite this, the PSA test is a very important, highly recommended screening. The American Cancer Society recommends an annual PSA test for all men beginning at age 50 and for younger men who are at high risk for prostate cancer (see "What are the Risk Factors?").
If a test indicates an elevated PSA or a doctor has other reasons to suspect prostate cancer, a prostate ultrasound may be conducted. In this procedure, a probe is placed in the rectum and sound waves are emitted. The sound waves are converted into pictures that allow doctors to determine if cancer or enlargements of the prostate are present. If a possible cancer is seen on the ultrasound, an ultrasound-guided biopsy may be performed. In this procedure, ultrasound is used to guide a needle into the prostate to remove a sample of tissue, which is then examined under a microscope to determine if cancerous cells are present.
The American Urologic System classifies prostate cancer into the following progressive stages:
- Stage A or Stage I (earliest stage): The cancer cannot be felt during a rectal exam. The cancer cells are contained within the prostate and have not spread to surrounding lymph nodes.
- Stage B or Stage II: The cancer cells are still contained within the prostate and have not spread to surrounding lymph nodes. The cancer can be felt during a rectal exam or found when a biopsy is performed.
- Stage C or Stage III: The cancer has spread to nearby tissues.
- Stage D or Stage IV (most serious stage): The cancer has spread to lymph nodes or to other parts of the body (known as "metastasis").
Prostate cancer can also be classified by the Gleason grading system, by which a number of 1 to 10 is assigned based on how closely the arrangement of cells in the cancerous tissue resembles normal prostate tissue. If the cancerous tissue resembles normal prostate tissue, a grade of 1 is assigned. Grades 2 to 4 indicate intermediate features, meaning the cancer has not spread throughout the prostate. If the cancer appears to be spread haphazardly throughout the prostate, a grade of 5 or 6 is assigned. Grades from 7 to 10 are considered severe and indicate a poorer prognosis.
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What is it?
