Why aren’t decision aids for prostate cancer screening working?

June 28th, 2019

Making decisions around prostate cancer screening can be difficult, because prostate cancer can be life-threatening, but in many other cases, prostate cancers never become harmful and patients are subjected to unnecessary treatment that affects their quality of life. Taking a PSA (Prostate-specific antigen) test to screen for prostate cancer has been shown to save few lives, while putting many more at risk of false positives and overtreatment.

However, patients have different values when it comes to cancer screening; some may prefer to do everything possible to learn their risk of prostate cancer, while others may consider the potential complications of overtreatment as more important. This is why the US Preventive Services Task Force recommends not routinely screening men for prostate cancer, but instead having a discussion about the benefits and harms of screening first. 

Often, clinicians use decision aids to inform patients about the benefits and risks of treatment and gauge patient preferences. Using decision aids in discussions with patients should theoretically affect patients’ screening decisions for the better. However, in a new study in JAMA Internal Medicine, researchers found that decision aids are having no effect on whether or not patients decide to get screened.

Does this mean we should stop using decision aids for prostate cancer screening conversations? Not necessarily, write Dr. Laura Scherer and Dr. Grace Lin in an accompanying commentary. Decision aids vary widely in their messaging, communication method, and where the tools were implemented. For example, a 1-page flyer mailed to patients that explains the benefits and harms of PSA tests is not the same as a video and coaching session offered to patients in the clinic.

Another significant difference between decision aids is the use of images and data to explain the potential harms and benefits. Some decision aids list the harms and benefits of PSA testing, but do not explain how likelihood of being helped or harmed, making it seem equally likely that screening will lead to saving one’s life as it will lead to overtreatment. In reality, it is much more likely that patients will be overtreated than they will catch an aggressive cancer, as this decision aid clearly shows.

Additionally, decision aids are likely not as influential to patients’ screening decisions as are the opinions of clinicians discussing screening. While information offered in decision aids can be helpful, the most important piece of information is often the answer a clinician gives to the question, What would you do in my situation? “Physician recommendations can be highly persuasive, potentially overriding patients’ informed preferences,” write Scherer and Lin.

Another reason decision aids for prostate cancer screening may not be working is because they are small measures compared to the massive amount of pro-screening information people are exposed to in the media. When “screening saves lives” is the predominant message from health care institutions, it may take more than one conversation to convey the potential harms of screening.