Taylor and colleagues present findings of, to our knowledge, the largest clinical trial of a PSA decision aid to date. They randomized 1893 men to receive a print-based decision aid, a web-based decision aid, or no decision aid (usual care) and observed them for 13 months. They found that men who viewed either the print or web-based decision aid demonstrated modestly higher knowledge scores regarding prostate cancer and had less decisional conflict 1 month following the intervention. Importantly, they also found that these effects persisted at 13 months, suggesting that men retained the knowledge gained by viewing the decision aids and internalized a reduced sense of conflict from viewing them. The investigators also found that improved decisional satisfaction persisted at 13 months among recipients of the print decision aid but not among recipients of the web-based version. The rate of prostate cancer screening among all participants over the 13 months remained virtually unchanged (at 59%), and neither the print nor the web based decision aid had any effect on screening rates compared with usual care. [...]
This study also points to important challenges in defining and achieving high-quality decision-making processes for prostate cancer screening. The intervention groups demonstrated modest increases (2.5 points on an 18-point scale) in prostate cancer knowledge.
The lack of a difference across study arms in prostate cancer screening rate surprises me. Perhaps, as Reuland and Pignone suggest, the increase in knowledge by intervention groups was insufficient to overcome “overcome prior misunderstandings regarding potential benefits and harms from screening.”