Decision-Making for Preventive Interventions in Asymptomatic Patients

The decision to treat an incidental finding in an asymptomatic patient results from careful risk-benefit consideration and is often challenging. One of the main aspects is after how many years the group who underwent the intervention and faced the immediate treatment complications will gain a treatment benefit over the conservatively managed group, which maintains a lower but ongoing risk. We identify a common error in decision-making. We illustrate how a risk-based approach using the classical break-even point at the Kaplan-Meier curves can be misleading and advocate for using an outcome-based approach, counting the cumulative number of lost quality-adjusted life years instead. In clinical practice, we often add together the yearly risk of the natural course up to the time point where the number equals the risk of the intervention and assume that the patient will benefit from an intervention beyond this point in time. It corresponds to the crossing of the Kaplan-Meier curves. However, because treatment-related poor outcome occurs at the time of the intervention, while the poor outcome in the conservative group occurs over a given time period, the true benefit of retaining more quality-adjusted life years in the interventional group emerges at a much later time. To avoid overtreatment of patients with asymptomatic diseases, decision-making should be outcome-based with counting the cumulative loss of quality-adjusted life years, rather than risk-based, comparing the interventional risk with the ongoing yearly risk of the natural course.