| Common Prostate Cancer Questions | |
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Where is the prostate and what does it do? The prostate is one of the male sex organs. The other major sex organs in men are the testicles and the seminal vesicles. Together, these glands store and secrete the fluids that make up semen. The prostate is usually about the size of a walnut and lies just below the bladder and surrounds the upper part of the urethra. The urethra is the tube that carries urine from the bladder and semen from the sex glands out through the penis. As one of the sex glands, the prostate is affected by male sex hormones. These hormones stimulate the activity and growth of the prostate cells. The main male sex hormone is testosterone, which is produced almost entirely by the testicles. Facts about Prostate Cancer Prostate cancer is the most common cancer diagnosed in the United States with over 215,000 men diagnosed last year. It is currently the second most common cause of cancer death in men who live in the U.S. Its cause is still unknown, although some cancers are probably passed down genetically while others are likely associated with environmental or dietary factors. About 1 out of every 6 men will be diagnosed with prostate cancer during their lifetime. Even though it is extremely common, the good news is that only about 1 out of every 27 men who are diagnosed will actually die of prostate cancer. Part of the reason for this is our improved ability to detect prostate cancer early and also our ability to effectively treat it these days. Overall, prostate cancer is usually slow growing compared to other types of cancer. Prostate cancer typically begins in the outer part of the prostate gland. When confined within the prostate, it is called localized disease. However, like other malignancies, prostate cancer can metastasize or spread to the lymph nodes, bones, or other parts of the body. How is prostate cancer diagnosed? Prostate cancer rarely causes any symptoms until it has progressed to an incurable stage. Thus, the best way to diagnose prostate cancer is through screening as part of an annual physical examination with your doctor. Screening involves a digital rectal exam (finger exam) and a prostate specific antigen (PSA) blood test. The American Cancer Society currently recommends that all men age 50 and older should be screened for prostate cancer. Patients with relatives who have prostate cancer and African-American patients should begin screening earlier. If either the digital rectal exam or PSA is abnormal, a prostate biopsy is performed to see if cancer is present. What is the digital rectal exam? The digital rectal examination can detect cancer and judge whether it is confined to the prostate. Because it lies in front of the rectum, the doctor can feel the prostate by inserting a gloved, lubricated finger into the rectum. Many times, early cancers are not able to be felt by rectal examination because they are too small. What is PSA? Prostate specific antigen (PSA) is a protein produced by both normal and cancerous prostate cancer cells. When prostate cancer grows or when other prostate diseases are present, the amount of PSA detected in the blood often increases. Currently, an increased PSA level is the most common way that prostate cancer is detected. How is a prostate biopsy performed? A transrectal ultrasound of the prostate is first performed to examine the prostate. Ultrasonography allows the urologist to measure the size of the prostate and see if there are any particularly suspicious areas. The urologist also uses the ultrasound to direct a local anesthetic into the prostate area to numb the area before the biopsy. A spring-loaded needle is then placed through the ultrasound probe and then using the ultrasound to target certain areas of the prostate, about 10-14 biopsies are performed. Each biopsy removes a small core of tissue, which is then examined under the microscope to see if prostate cancer cells are present. How is prostate cancer graded? A pathologist named Gleason described the grading system for prostate cancer based on the pattern of cancer cells, now called the Gleason score. The Gleason grade reflects how aggressive the prostate cancer is likely to behave. Each area of prostate cancer is graded on a scale of 1 to 5 (with 5 being the most aggressive). The pathologist looks at all of the biopsies and then assigns a grade to the two most common patterns seen. These two grades are then added together to determine the Gleason score or Gleason sum. Therefore, the resulting Gleason score will always be a number between 2 to 10 (i.e. 3 + 4 = 7/10). These days, it is rare to see cancers that have a score of 2 to 5. Most cancers are either a 6 or higher. The higher the number, the more aggressive the prostate cancer will usually behave. How do you stage prostate cancer? Stage refers to whether the cancer is confined or appears to have spread outside the prostate. There are several tests that may be useful in determining tumor stage. Not all of these tests are needed in all men. In fact, most men with early cancers have such a low chance of having cancer elsewhere in the body that none of these tests are warranted. CT Scan – Computed tomography (CT scan) is an x-ray procedure that gives images of the body. It can help to detect lymph nodes in the pelvis that are enlarged because of cancer. This test is usually used for intermediate or high-risk patients only. MRI – Magnetic resonance imaging (MRI) is similar to a CT scan except that it uses magnetic fields instead of x-rays to create internal pictures of your body. While standard MRI has limited additional usefulness for prostate imaging, a new MRI technology called endorectal coil MRI is sometimes useful for determining whether cancer is extending outside the prostate near the nerves that control erections. Bone scan – This test is performed when there is suspicion that cancer has spread to the bone. A small amount of radioactive tracer material is injected into the bloodstream and, a few hours later, a scanner is used to pinpoint areas where the tracer material collects. When this tracer material collects in the bone, it is concerning for spread of cancer into the bone. Lymph node dissection – The lymph nodes are usually the first location where prostate cancer spreads once it leaves the prostate. Using information such as your PSA level, digital rectal exam results, and Gleason score, your urologist can estimate the risk that cancer has spread to the lymph nodes. If there is a very low risk that the cancer has spread, a lymph node dissection is not typically performed. If there is a higher chance of lymph node spread, they are sometimes sampled in the operating room to more accurately stage an individual patient’s cancer. Clinical Stage Clinical tumor stage refers to whether or not the tumor can be palpated or felt on exam and whether it may have spread outside the prostate. The tumor-node-metastasis system (TNM) is used to designate the clinical stage. AJCC 6th edition (2002) Evaluation of the (primary) tumor ('T') • TX: cannot evaluate the primary tumor • T0: no evidence of tumor • T1: tumor present, but not detectable clinically or with imaging • T1a: tumor incidentally found in < 5% of prostate tissue resected (for other reasons) • T1b: tumor incidentally found in > 5% of prostate tissue resected (for other reasons) • T1c: tumor found in a needle biopsy performed due to an elevated serum PSA • T2: tumor can be felt (palpated) on examination, but has not spread outside the prostate • T2a: tumor palpated in half or less than half of one of the prostate gland’s two lobes • T2b: tumor palpated in more than half of one lobe of the prostate • T2c: tumor palpated in both lobes of the prostate • T3: tumor palpated on examination and appears to have spread through the prostatic capsule • T3a: tumor spread through the capsule on one or both sides of the prostate • T3b: tumor has invaded one or both seminal vesicles • T4: tumor has invaded other nearby structures/organs Evaluation of the regional lymph nodes ('N') • NX: cannot evaluate the regional lymph nodes • N0: there has been no spread to the regional lymph nodes • N1: there has been spread to the regional lymph nodes Evaluation of distant metastasis ('M') • MX: cannot evaluate distant metastasis • M0: there is no distant metastasis • M1: there is distant metastasis • M1a: the cancer has spread to lymph nodes beyond the regional ones • M1b: the cancer has spread to bone • M1c: the cancer has spread to other sites (regardless of bony involvement) Do I have low risk, intermediate risk, or high risk prostate cancer? Prostate cancers can be classified based on the clinical stage, PSA level, and Gleason grade into risk categories. This is important for deciding what treatments may be most appropriate. Low Risk: clinical stage T1c or T2a, serum PSA of <10 ng/ml, AND biopsy Gleason score of 6 or less. Men with low-risk prostate cancer have about an 85% or better chance of being cancer-free in 10 years with either surgery or radiation. Intermediate Risk: clinical stage T2b, serum PSA 10-20 ng/ml OR biopsy Gleason score of 7. Men with intermediate risk prostate cancer have about a 50% chance of being cancer-free in 10 years after treatment. High Risk: clinical stage T2c or higher, serum PSA >20 ng/ml OR biopsy Gleason score of 8 or higher. Men with high-risk prostate cancer have about a 33% chance of being cancer-free in 10 years after treatment. |
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