A good screening test is relatively inexpensive and noninvasive. In addition, effective treatment should be available if the disease being screened for is confirmed. Lastly, detecting the disease before a patient becomes symptomatic must be more beneficial than detection after the patient experiences signs or symptoms.
The latter point is often debated in prostate cancer screening, which is done by obtaining a serum prostate specific antigen (PSA) and performing a digital rectal exam (DRE). Some studies have found no mortality benefit with prostate cancer screening. Another study found an absolute risk reduction of 0.71 per 1000 men which translates to over 1400 men needing to be screened to prevent one prostate cancer death.
Even more confusing than the data are the guidelines. The American Urological Association and the American Cancer Society recommends annual PSA testing and digital rectal exams starting at 50 years old in men with normal risk of prostate cancer. The U.S. Preventive Services Task Force (USPSTF), however, states the evidence is insufficient to fully support or completely do away with prostate cancer screening, making it up to the doctor to discuss the pros and cons with patients.
Ultimately, it is our job as physicians to help patients make sense of all the controversy so they can make an informed decision about undergoing screening. Liberatore et al summarized several studies that found that patients decided not to have PSA testing after watching informational videos. Showing every patient a video, however, is not always practical in the clinical setting. Physicians often have about 5 minutes or less to discuss prostate screening with patients. Below are some points to highlight to patients in the limited amount of time we have to counsel and help them make a decision about prostate cancer screening.
- Why is prostate cancer screening done and what does it entail?
We screen with a rectal exam to see if the prostate is irregular and/or enlarged and a simple blood test that detects a protein produced by the prostate that may identify prostate cancer in its early stages.
- Who gets the test?
Prostate cancer screening typically begins at age 50 for men with normal risk. African-American men or men with a family history can be screened earlier.
- What if the exam or blood test is positive?
If the exam or blood test is positive, it doesn’t immediately mean that you have prostate cancer. Benign prostatic hyperplasia (BPH) is a non-cancerous condition that can cause elevated prostate protein or an enlarged prostate. If the blood test is positive, often it is repeated for confirmation and if it is still high, a prostate biopsy is recommended and performed by a urologist.
- What if the biopsy shows cancer?
If the biopsy results show cancer, treatment options include surgery, radiation treatment, and/or medication. These treatments, however, come with risks such as sexual or urinary dysfunction.
- Should I undergo screening?
Many men have prostate cancer that is never detected and never causes harm. These are low risk cancers. Also, some studies have shown that, as a group, patients who are screened and then treated for detected prostate cancers do not have reduce deaths from prostate cancer when compared to patients who did not receive screening. Then again, we cannot 100% guarantee that low risk cancers will never progress to more aggressive cancer. So, if you do undergo testing and cancer is detected and treated you are faced with risks from treatment yet we may have prevented a low-risk cancer from progressing. If you do not undergo the screening, it is possible, yet this is a low possibility, that a low risk cancer can progress to more aggressive forms. It is unlikely, however, that we would have changed your risk of death from prostate cancer if you were screened and treated.
Some patients will be able to make a decision from the above information. Some, however, defer the decision to you—their doctor. In my mere experience as an intern, when I am asked to make the decision for my patient, I ask them if there is something I can elaborate further from our above discussion. If they are still ambivalent, I order a PSA, especially if a patient has a family history. My reasoning behind ordering the test is as follows: if in the event that the PSA does come back positive (>4 ng/ml), the patient does not necessarily have to undergo treatment or even a biopsy if the level is borderline. He can have an ongoing conversation, similar to the above, regarding the risks and benefits of treatment with you or a urologist. He may choose active surveillance, an option for patients with low risk cancers or patients who do not wish to have treatment if their results are abnormal. Active surveillance consists of PSAs and DREs every 6 months and/or a biopsy every 1-2 years. Thus, even with a diagnosis or suspicion of prostate cancer, patients still have the option to have treatment or not. The battle against overdiagnosis and overtreatment of prostate cancer can be fought by counseling our patients about the risks and benefits of screening and treatment.
In summary, the benefit of prostate cancer screening is indeed controversial. Until more data is available or guidelines become more unanimous, the best we can do is ensure that patients are making well informed choices about screening.
Caprice Cadacio is a medical resident who blogs at Clinical Correlations, where this post originally appeared.
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