Personal risk factors for prostate cancer, such as your age, general health, race and family history, may not be enough to determine whether you should be screened.
In fact, many men who have undergone screening for prostate cancer wish they had considered other issues in addition to these risk factors, such as potential dilemmas that their screening results may have presented.
Having a clear picture of the dilemmas and uncertainties that prostate cancer screening results can bring—in addition to assessing your risk factors—is the best way to ensure that you make screening decisions you'll feel comfortable with down the road.
Uncertainty #1: Early-Stage Treatment Doesn't Always Improve Outcome
Unlike many cancers, there is a big difference between prostate cancer incidence and mortality. Having the disease is not a death sentence. Many men who have prostate cancer do not die from it, even when it is left untreated, because their particular cancer is slow growing. Not only are many slow growing, but also they often don't cause any symptoms at all during a man's lifetime and are unlikely to be a cause of death or disability.
However, some prostate cancers grow more quickly, and it is difficult to tell in the early stages which cancers pose a threat and whether early treatment is desirable. So even if the prostate cancer screening process works and a cancer is detected, it may not be clear in all cases whether treatment will cause more good than harm. A number of men opting for treatment will be cured. However, other men may find themselves dealing with the side effects of surgery and radiation for a cancer that would never have bothered them had it gone undetected.
Consider this: By the age of 80, half of all men will have some cancer cells in their prostate, but only 1 in 30 will die from it.
Uncertainty #2: Don't Expect Proof-Positive Results
In the absence of prostate cancer symptoms, two main tests are currently used to detect prostate cancer: a digital rectal exam (DRE) and a blood test to detect a substance made by the prostate called prostate specific antigen (PSA).
The DRE is a long-established test used by physicians, but wide variations exist in how physicians interpret the findings. And false negatives are common. In fact, an overview of studies on screening suggests that DRE alone detects less than 60 percent of prevalent prostate cancers. About 25 percent of men who were diagnosed with metastatic prostate cancer had a normal DRE.
Bottom line: If DRE does not detect a cancer, it does not always mean that cancer is not there.
PSA testing detects more tumors than does DRE, and it detects them earlier. However, a PSA level of 4 or below doesn't always mean that you're cancer-free. Various factors may cause a drop in PSA levels even if you have prostate cancer. Herbal supplements such as saw palmetto and medications such as finasteride can reduce your PSA level.
Many men with an abnormal PSA may go through needless worry and medical procedures to find out they don't have cancer.
Using both DRE and PSA screening for prostate cancer appears to detect more cancers than using either method alone, and most experts recommend that men who want to be screened for prostate cancer have both tests.
Uncertainty #3: Don't Assume Positive Means Positive
The PSA test for prostate cancer is a tricky combination of high sensitivity, meaning it does a good job of finding a cancer if there is one, and low specificity, meaning a substantial number of high PSA readings will be due to some other condition and not due to cancer at all. Nevertheless, the higher the PSA, the more likely the presence of prostate cancer.
On the other hand, because PSA can rise for all kinds of reasons, this type of screening for prostate cancer produces a high percentage of false positives, which can lead to unnecessary, costly and invasive tests, such as biopsies, as well as unnecessary personal distress.
An elevated PSA level may be caused by benign prostate enlargement (prostatitis); inflammation or infection of the prostate gland; and age, race and/or physical or sexual activity. More than 70 percent of men with a PSA level between 4 and 10 don't have prostate cancer.
Because there is a considerable amount of uncertainty surrounding PSA values, efforts have been made to find more specific ways to measure PSA levels. Following your PSA levels over time to determine how fast they go up; scaling the results based on your age; comparing the size and weight of your prostate gland to your PSA level; and assessing the balance of the two different forms of PSA that circulate in your blood may bring more indicative results. Although these modifications to PSA testing have attempted to improve the test's predictive power, there is not enough evidence to show that any of these variations improve the accuracy of screening, with the possible exception of PSA velocity.
Prostate cancer screening tests that look for other biological markers are currently in development but are not yet commercially available. Scientists believe they are on track for finding a gene, or genes, that can indicate increased prostate cancer risk for some men—and have new evidence that a particular gene variant can indicate reduced risk for others. This puts researchers one step closer to being able to predict disease risk in individual men.
Dilemma #1: Screening May Lead to More Screening
Although a positive screening result may not mean cancer is present, in general, positive results or elevated PSA levels cannot be ignored. But since PSA levels vary from one test to another, you may want to have the test repeated. Following a positive result, your healthcare provider will likely recommend follow-up tests and investigations, such as a prostate biopsy, in order to reach a diagnosis. A biopsy is the only test that can show whether cancer cells are present.
Although a biopsy is done quickly, it can be uncomfortable, so talk with your doctor beforehand about a local anesthetic.
Dilemma #2: Prostate Cancer Screening May Lead to Treatment
Although relatively safe, having a biopsy is a significant event because if the results are positive, you'll need to make some difficult decisions regarding treatment.
The prostate is located just beneath the bladder, close to the nerves that are important for erections and that surround the urinary outlet tube. Because of this, most treatments for prostate cancer—such as removal of part or all of the prostate (radical prostatectomy) or radiation therapy to shrink or kill the cancer—can affect potency and continence.
Compared with watchful waiting, these aggressive treatments have not been shown to reduce morbidity or mortality for localized prostate cancer.
Therefore, if the cancer is small and localized and is low grade (not aggressive), you may want to opt for watchful waiting. Men who are undecided about treatment, are over 80 years old, or have a serious illness often take this route.
Dilemma #3: Early Detection Does Not Ensure a Cure
Although prostate cancer screening aims to detect cancer at a very early stage, prostate cancer is not a homogeneous disease.
Every man's cancer is different, and some cancers are more biologically aggressive than others. Aggressive cancers, found most often in young men, grow and metastasize rapidly and are very likely to have spread to other parts of the body by the time they are detected via PSA testing.
Digital rectal exams can only detect tumors that are relatively large and often too advanced to be curable. In one study, 20 percent of prostate cancers detected via DRE had spread beyond the prostate at the time of diagnosis.
Prostate screening also carries a high risk of overdiagnosis. That means many men are diagnosed with prostate cancers that never would have threatened their health.
Factoring all this in, there is a lot of controversy about whether the value of early diagnosis of prostate cancer is sufficient to outweigh the risks that are associated with disease treatment, such as erectile dysfunction, incontinence, anxiety, morbidity and mortality.
Make an Informed Decision with Your Doctor
Considering the research results to date, the U.S. Preventive Services Task Force recommends that men age 55 to 69 have an informed discussion with their doctors about whether they should get screened. Not all men are appropriate candidates for prostate cancer screening. Some who undergo screening will benefit from it, some will not and some may be harmed by it.
Given this variation, when considering prostate cancer screening, it's important that you work with your healthcare provider and take into account the benefits and risks of diagnostic procedures and treatment, as well as your individual risk profile and your personal preferences.
