By Cat Troiano
According to the American Cancer Society, one out of nine men is diagnosed with prostate cancer, and it is the third leading cause of cancer-related death in men. The present survival rate, in which one out of 41 men succumb to the illness, is higher than the alarming rate of diagnosis, thanks to screening tests.
Risk Factors and Testing Guidelines
Cases of prostate cancer are often detected before any symptoms present. Men who are experiencing changes in urination habits or in reproductive function should consult with their physician, who will order a prostate-specific antigen test and a digital rectal examination at once to screen for prostate cancer. In the absence of these signs, prostate cancer screening recommendations are made based upon each patient’s age and risk factors.
• Men who are 50 years of age or older and have a remaining life expectancy of at least 10 years should undergo prostate cancer screening.
• Prostate cancer screening should begin at 45 years of age in men who have elevated risks of developing the illness.
Such risks include:
o Being African-American
o Having a father, son or brother who was diagnosed with prostate cancer before the age of 65
• Men who have a family history of two or more direct relatives who were diagnosed with prostate cancer before the age of 65 should undergo prostate cancer screening from the age of 40.
Prostate cancer is a slow-growing cancer, and thus screening is not typically advised for men who do not have an expected remaining lifespan of at least 10 years. In these cases, the men who happen to have prostate cancer will more likely die with prostate cancer rather than from prostate cancer.
What Is PSA?
The prostate is a male reproductive gland that is located underneath the bladder and in between the seminal vesicle and the rectum, and it surrounds the uppermost portion of the urethra. The prostate’s role is to produce prostate fluid, which combines with semen, and to expel semen into the urethra during ejaculation. Prostate-specific antigen (PSA) is a protein enzyme that breaks down the molecular weight of proteins in semen, rendering semen a more fluidlike form. PSA is produced by both healthy and cancerous cells of the prostate gland, and while much of it is released into semen, some is also released into the bloodstream. Men who have prostate cancer will have a significantly higher concentration of PSA in their blood.
Using PSA as a Tumor Marker
The PSA test, which is performed on a blood serum sample, is used as a tumor marker screening method. The most commonly ordered laboratory test for prostate cancer screening is the total PSA test, which provides results that represent the sum of two forms of PSA in the blood. The two forms are known as free PSA and complexed PSA. Free PSA is that which is not bound to other proteins in the blood, a presentation that is more typical from benign, or noncancerous, prostate cells. Complexed PSA, or cPSA, is that which binds with other proteins and is a more typical result from malignant prostate cells. If the total PSA test result is slightly higher than the normal reference range, then a free PSA test may be ordered to help guide physicians in the decision of whether or not to pursue the recommendation of a prostate biopsy. If the free PSA level is high, then the high total PSA level may be the result of a benign condition as opposed to prostate cancer.
The PSA Test Result
The general normal reference range for a PSA test is less than 4 ng/mL in men who are less than 60 years of age.
As long as the result is less than 2.5 ng/mL, the American Cancer Society recommends repeated screenings every two years. If the result is 2.5 ng/mL or greater, then screenings should be ordered annually. The upper normal reference range limits for PSA levels increase in men beyond 60 years of age. The reference ranges for older age groups are:
• 4.5 ng/mL or less for men aged 60 to 69
• 6.5 ng/mL or less for men aged 70 to 79
• 7.2 ng/mL or less for men aged 80 or older
A digital rectal examination (DRE) to palpate the prostate for any lumps, enlargement or other physical abnormalities is performed as part of a routine physical examination. Blood should be drawn before performing a DRE since this can temporarily elevate the PSA level in some patients.
There are other noncancerous causes of an elevated PSA result. Some of these conditions include:
• Benign prostatic hyperplasia, more commonly referred to as an enlarged prostate, is a condition in which the prostate cell production and growth accelerates. The result is a larger prostate that can compress the urethra, which can potentially cause partial or complete urinary blockage. Benign prostatic hyperplasia is part of the aging process and affects most men as they age.
• Prostatitis is an infection of the prostate which is often bacterial in nature. Unlike benign prostatic hyperplasia, prostatitis can affect men of any age, but it is more commonly diagnosed in those who are less than 50 years of age.
• Urinary catheterization or any medical procedure that can cause irritation or inflammation of the prostate and surrounding structures can lead to an elevated PSA level.
• Ejaculation within 24 hours prior to testing can cause a slight elevation in PSA, which may raise a red flag in someone whose normal PSA level has been borderline on previous screenings.
• Aging raises the normal limits of the PSA level, as noted above.
• Certain chemotherapy drugs can alter the PSA level.
If a PSA test result is higher than the accepted normal range, further diagnostic testing will be ordered to rule out cancer as the cause. Such tests typically include a trans-rectal ultrasound and prostate biopsy. If the pathology report confirms the presence of cancerous cells, the PSA test results can be used in conjunction with the histopathology results as part of the cancer staging process.
Prostate Cancer Treatment Options
Once a patient is diagnosed with prostate cancer, treatment options should be discussed with an oncologist. Some options that are available include:
• Prostatectomy, which is surgical removal of the prostate
• Brachytherapy, or internal radiation therapy, such as the implantation of radioactive seeds
• External beam radiation therapy, such as CyberKnife® radiation
• Cryotherapy, or cryoablation, in which prostate cancer cells are destroyed by freezing
• Hormone therapy to lower the body’s level of androgen, which is a male hormone that stimulates the growth of prostate cancer cells
• Chemotherapy
When discussing treatment options, factors such as age, expected lifespan, the stage of the cancer, the presence of other health conditions and patient concerns regarding potential side effects of treatment must all be considered. Once a treatment protocol has begun, PSA tests can serve to monitor the efficacy and progress of the treatment. Decreasing levels of PSA indicate that the treatment is working.
All male patients should have a prostate cancer risk assessment discussion with their primary care physicians at age 40, and PSA testing should then be ordered in accordance with screening guidelines. PSA testing should also be ordered for all male patients who present with any signs of symptoms of possible prostate problems. Four out of five cases of prostate cancer are diagnosed during the early stage, and when treatment is promptly sought, the 15-year relative survival rate is 96 percent.