Prostate-Specific Antigen Screening for Prostate Cancer: Yes, No, or Maybe?

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This is particularly relevant to the prostate issue. Because prostate cancer screening, by definition, involves men who are asymptomatic at the time that we’re proposing it, and given that there’s clearly uncertainty regarding the overall balance between benefits and harms, it really is vital to allow the patient to be part of the decision.

This is essentially an ethical issue. Before we potentially cause harm, we should certainly have the patients agreement; we should know that they want to proceed with the intervention—in this case, prostate cancer screening. That’s the reason why informed decision making—and in this case, shared decision making—is so important.

Shared decision making implies not only that the patient is informed but also that the healthcare provider is engaged in the decision-making process by assisting the patient in making the decision whether or not to be tested for prostate cancer.

One element of this process is that the patient has the information to understand why screening is controversial. The patient should understand the potential benefits of screening, which, of course, include potentially preventing death from prostate cancer.

There are many potential harms, including harms related to the initial PSA screening with or without the DRE, which are negligible risks; however, the problems associated with biopsy are not insubstantial, primarily in terms of the infection risk and bleeding risk. One Medicare database study reported a hospitalization rate of up to 0.45% for urinary or prostate infection in men who have had a prostate biopsy.22

The problems associated with treating screen-detected prostate cancer are well known and include sexual dysfunction, urinary incontinence, bowel injury from radiation, death on the operating table, and postoperative death. Patients should be aware of these elements before they launch into the screening process.

Since this is such a value-dependent decision, physicians can play a critical role in helping patients to articulate their values and subsequently integrate these values into the screening decision. For example, is it more important to the patient to try to avert death due to prostate cancer or to avoid complications such as sexual dysfunction, urinary incontinence, or bowel injury incurred while treating a cancer that might never have harmed them?

DR. HOFFMAN: One thing that I really appreciate about the ACS guidelines is that while encouraging informed decision making, they recognize that physicians and patients often don’t have the time to adequately discuss screening. The physicians may also not have readily available information on benefits and harms; therefore, the ACS recommends using decision aids. Dr. Volk, could you describe decision aids and how we should use them? Do we know whether they’re effective?

DR. VOLK: The question really is that with all this wonderful evidence, how can we expect clinicians to have a conversation with patients about the potential harms and benefits of screening, all within the context of a very limited encounter? It just takes a lot of time, and decision aids can be quite helpful in this situation.

Decision aids are tools that help patients think about their choices. They provide patients with information about their options in a balanced way. They help people to deliberate or think about their options, pursue more information, and consider what it would be like if they decided to choose either option.

For prostate cancer screening, some very useful tools have been developed. We mentioned that the ACS developed a prostate cancer-screening decision aid after its guidelines were released, and there are other aids too. The Informed Medical Decisions Foundation has a very useful tool, and the Centers for Disease Control and Prevention has a tool as well. Thus, there are some very helpful decision aids that are available.23–25

Decision aids are developed to help move some of the educational burden off the clinician and help the patient to have a meaningful conversation about what their values and preferences are so that they can make a decision in collaboration with their health care provider that’s best for them.

A large number of randomized trials examining patient decision aids have been completed. Many are specific to prostate cancer screening, and invariably, they show that men learn a lot about the harms and benefits of screening. The tools don’t make men more anxious about cancer or making a decision, and they become more assured about the choices they make.

DR. HOFFMAN: I wanted to get everyone’s thoughts on what the future of screening is. Dr. Penson, what do you think lies ahead for prostate cancer screening?

DR. PENSON: This concept of risk-based screening is the future of prostate cancer screening. Eventually, we are probably performing too many PSA tests. We probably don’t need them on an annual basis, and we need to develop a more intelligent way to approach this topic in the men who want to undergo PSA testing. The biggest problem with screening, which we alluded to earlier, is the problem of overdiagnosis and overtreatment. We know that probably, one-third of the patients who are screened and in whom prostate cancer is detected have an overdiagnosed cancer. So, potentially, screening less often and screening only the patients who are most likely to have an increased risk for prostate cancer may reduce the overdiagnosis rate.

The other point that we really haven’t talked about—and I do think this is important for the future—is the concept of divorcing screening from treatment. We discussed about the harms of screening a little, and people tend to clump the harms of screening and treatment together.

There are harms to screening, specifically the harms of a biopsy if the screening test is positive. However, the harms of treatment (if the biopsy is positive) are avoidable by increasing the use of active surveillance as a treatment strategy. In other words, instead of taking a patient who has been diagnosed with prostate cancer, particularly a low-grade prostate cancer, and immediately operating on him or performing a radiation treatment for him, we manage him with active surveillance. There may be a real role for following those patients closely, with regard to monitoring their PSA levels, repeating biopsies over time, and effectively and actively surveying them. This reduces the complications associated with aggressive intervention and potentially improves the efficacy of screening.

DR. HOFFMAN: Dr. Volk, you have actually worked on a decision aid for prostate cancer treatment. Can you discuss the challenges of convincing men to select active surveillance?

DR. VOLK: I have done some work with the Eisenberg Center and the AHRQ on a web-based decision aid for prostate cancer treatment.26 We released this decision aid before the results of the Prostate Cancer Intervention Versus Observation Trial (PIVOT) were published, but we were certainly aware of the main findings from that important study.27

It takes some rethinking about prostate cancer. For example, a challenging idea for patients is that there is a spectrum of risk: some cancers can have a lesser chance of progressing than others. What we’ve done with our decision aid tool is try to emphasize that patients should understand this spectrum of risk and talk with their healthcare provider about their options, including the option of careful monitoring of their cancer, if the risk is really low.

Active surveillance is more than watchful waiting—it is carefully monitoring the cancer for progression. Thus, it is a challenge to communicate the idea of a spectrum of risk and how this is related to treatment or management decision making. Active surveillance involves carefully monitoring, and if there is progression, there is still time to act.

DR. HOFFMAN: Finally, Dr. Wolf, do you have any other thoughts on the future of prostate cancer screening?

DR. WOLF: I have concerns about it, just because there is now such a divergence of national recommendations. When you have competing recommendations, which is the situation we are now in, physicians understandably don’t know what to do and they tend to continue whatever they were doing before. We don’t want physicians to be conducting blanket screening without informed decision making; on the other hand, we may lose opportunities to target screening for men who might want it and benefit from it but won’t be offered screening based on the USPSTF recommendation.

I think that the USPSTF made an important error in giving prostate cancer screening a “D” recommendation. My feeling is that the evidence would best support a “C” recommendation, meaning that men should not be routinely screened but instead should be informed of the risks and benefits and allowed to decide for themselves.

I also agree with the others in that active surveillance should be part of what is offered if a low- or moderate-grade prostate cancer is detected. That approach is used much more readily in Europe and may partly explain why the Goteborg European trial demonstrated such a low “number needed to treat” (12 men with screen-detected prostate cancer treated to avert one cancer death over 14 years of follow-up).21 This number is much lower than that in the European study overall and compares favorably with other cancer screens such as mammography and even colorectal cancer screening.

DR. HOFFMAN: Thank you, everyone. I really appreciate your participation and very insightful comments.

UPDATE

The AUA recently updated their position on PSA screening.20 The previous AUA recommendations were based upon expert opinion and the consensus process, while the new guidelines are evidence-based developed using a process based upon the Institute of Medicine's recommendations on guideline development. In short, the AUA guidelines now recommend informed decision making for PSA screening for men aged 55-69 years at average risk for the disease. In this setting, men should be informed of the risks and benefits of screening and should undergo screening if they feel it is in their best interests after this discussion. In men over age 70 years at average risk or those with less than a 10-year life expectancy, the guidelines recommend against routine screening, although they do acknowledge that there may be a role for informed decision making in particularly healthy men over the age of 70 years. Perhaps, the most controversial element of the new AUA guidelines is the fact that they do not recommend routine screening in men aged 40-54 years at average risk for prostate cancer. This is somewhat different from explicitly recommending against screening. The panel felt that because there was currently no evidence showing a significant benefit to screening in this age group, while there were some documented harms associated with screening, it could not endorse routine population-wide screening. However, the panel did note some evidence showing a relationship between elevated PSA levels in men in their 40s and increased risk of prostate cancer metastases and death later in life. Because of this, the panel felt that “the absence of evidence does not mean an evidence of absence” and stopped short of explicitly recommending against screening in this younger age group. It is important to remember that the AUA guidelines only apply to men at average risk and that men at an increased risk of disease (strong family history and African-American race) are encouraged to discuss screening with their provider and make an informed decision regarding testing, regardless of their age.

The American College of Physicians (ACP) also recently issued a guidance statement based on their review of screening guidelines developed by other organizations.28 The ACP also supported shared decision making for men between the ages of 50 and 69 years, advising clinicians to inform these men about “the limited potential benefits and substantial harms of [PSA] screening for prostate cancer.” They also recommended against PSA testing for average-risk men under the age of 50 years or over the age of 69 years and for men with a life expectancy less than 10 years. With these new publications, there is now a consensus among professional organizations against routine screening. Instead, men between the ages of 50 and 69 years should be supported in making informed decisions that reflect their preferences.

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