Prostate Cancer Screening: Let Patients Decide
Am Fam Physician. 2008 Dec 15;78(12):1338.
This issue includes a well-done review of the controversy about prostate cancer screening.1 Wilbur concludes that current guidelines recommend shared decision making through an individualized, targeted, patient-centered discussion. Updated guidelines from the U.S. Preventive Services Task Force (USPSTF)2 and supporting data3 are consistent, concluding that there is insufficient evidence to assess the benefits versus harms of screening in men younger than 75 years. However, the USPSTF recommends against screening men 75 years or older.2
No good-quality randomized trial of screening has been done, and only one randomized trial on surgical treatment of prostate cancer exists.4 This trial included a small number of men with screening-detected cancers, and many had T2 (palpable) cancers. The biologic behavior of T2 cancers is likely quite different from cancers detected by prostate-specific antigen testing. Overall, disease-specific mortality decreased from 14.9 to 9.6 percent, and all-cause mortality decreased from 32 to 27 percent at 10 years. However, subgroup analysis showed no reduction in death from prostate cancer for patients who were 65 years or older at enrollment.
Without good evidence on the net benefit or harm of prostate cancer screening in young men, the decision of whether to screen this age group will reflect the values of the decision makers. For a disease as prevalent and important as prostate cancer, it should be the patient's values, not those of the physician or guideline panels, that are incorporated into the decision. These points may be discussed to help patients with this decision:
Prostate cancer is prevalent. If everyone in the age range in which screening is commonly recommended received a biopsy, prostate cancer could be detected in as many as 25 percent. In contrast, the lifetime risk of death from prostate cancer is only about 3 percent, and most of these deaths occur after 75 years of age.5
Using a conventional cutoff of greater than 4 ng per mL (4 mcg per L) for an abnormal PSA test result, initial screening detects cancer in 3 to 5 percent of men.6
Treatment of prostate cancer is not benign. As many as one in 200 men will die from complications of treatment.7,8 The majority will have sexual dysfunction, and a small but meaningful minority will have urinary incontinence.9
For some, detection and treatment will likely prolong their lives. For others, detection will cause adverse effects from unnecessary treatment of a disease that would not have become symptomatic. Science does not allow us to estimate how many men are in each group.
I would conclude a shared decision making discussion by describing two men, and asking the patient which of these men he can identify with most: (1) men who would say, “Look, I feel well. Unless you are certain you can do me more good than harm, leave me alone;” (2) men who would say, “I'm afraid of cancer. If I have a cancer, I want to know and do something about it. I understand that there are risks.”
Men who value a “first, do no harm” approach should not be screened, whereas those who prioritize detection and treatment in the context of uncertainty should be screened. There is no bad decision, but it should be a shared decision, not made only by a physician or guideline panels. Hopefully, forthcoming studies will better inform discussions about prostate cancer screening.
1. Wilbur J. Prostate cancer screening: the continuing controversy. Am Fam Physician. 2008;78(12):1377–1384.
2. Screening for prostate cancer:. U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2008;149(3):185–191.
3. Lin K, Lipsitz R, Miller T, Janakiraman S. Benefits and harms of prostate-specific antigen screening for prostate cancer: an evidence update for the U.S. Preventive Services Task Force. Ann Intern Med. 2008;149(3):192–199.
4. Bill-Axelson A, Holmberg L, Ruutu M, et al. Radical prostatectomy versus watchful waiting in early prostate cancer. N Engl J Med. 2005;352(19):1977–1984.
5. National Cancer Institute. Surveillance Epidemiology and End Results. SEER cancer statistics review, 1975–2005. http://seer.cancer.gov.csr/. Accessed September 10, 2008.
6. Catalona WJ, Smith DS, Ratliff TL, et al. Measurement of prostate-specific antigen in serum as a screening test for prostate cancer [published correction appears in N Engl J Med. 1991;325(18):1324]. N Engl J Med. 1991;324(17):1156–1161.
7. Mark DH. Mortality of patients after radical prostatectomy. J Urol. 1994;152(3):896–898.
8. Zincke H, Bergstralh EJ, Blute ML, et al. Radical prostatectomy for clinically localized prostate cancer. J Clin Oncol. 1994;12(11):2254–2263.
9. Stanford JL, Feng Z, Hamilton AS, et al. Urinary and sexual function after radical prostatectomy for clinically localized prostate cancer: The Prostate Cancer Outcomes Study. JAMA. 2000;283(3):354–360.
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