Testing the effectiveness of a multi-criteria values clarification methods for patients with localized prostate cancer

The AHP method is a highly appropriate method to gain more insight into patients’ values and
treatment decisions, by structuring and breaking down the decision into smaller elements for
analysis. It encourages a process of pairwise comparisons of potential outcomes, which is needed for a patient to reach stabilized preferences. Furthermore, this VCM is able to explicitly present the calculated treatment option based on the scores that show how well or poorly each treatment option fits with the patients’ responses. This will be appropriate for patients who prefer actual treatment advice from the DA.



Currently, the effectiveness of this specific VCM, in addition to the existing DA, on the outcome
decision quality, is being evaluated in a prospective cohort study. In that study, decision quality is defined as congruence between well-informed patients’ values and the calculated and chosen treatment option. Additionally, results on disease-specific knowledge and preparation for decision making will be compared with a historical control group who only used the existing DA. Health literacy and numeracy will also be assessed to evaluate if the patients with low numeracy and/or low health literacy benefit from the VCM. Furthermore, the VCM will be further evaluated on its usage and patients are able to include additional decision attributes that are not prespecified by the working group but are relevant to them.

We hypothesize that the addition of the newly developed web-based VCM to the exisiting decision aid will improve the support offered to patients in their decision-making process (improvement of disease-specific knowledge, feeling informed, and value congruence) and their decision quality (association between knowledge and value congruence).

To evaluate our outcomes we will use questionnaires at 3 timepoints.

T0 = directly after diagnosis and after informed consent is obtained (demographics, health skills, treatment preference)

T1 = After treatment decision is made (treatment preference, decisional conflict, satisfaction, knowledge, feasibility)

T2 = 6 months after T1 (regret, treatment satisfaction, perceived treatment)

The values clarification method (VCM) based on analytic hierarchy process (AHP) is appropriate to generate more insight into the decision making process of patients. AHP is most often used in health care at the policy and health technology assessment level, but AHP is also used as decision support tool in clinical decision making(14). The first step within AHP is to define the decision problem: what are possible treatment options and which considerations and criteria should be used to judge how well the treatment options meet the patient’s goal. The selected criteria are used in pairwise comparisons to determine their relative priorities (weights) in the decision. In addition, a second set of pairwise comparisons are used to derive weights for the performance of treatment options on the different criteria. The results can then be combined to create a quantitative measure on a ratio scale that indicates how well each of treatment options can be expected to meet the overall treatment goal. The AHP has been successfully applied to a variety of complex medical decisions, but its use in prostate cancer is limited and focused on prostate cancer screening decisions (15-17)
With this method, value congruence can be calculated by measuring the extent of agreement between the preferred treatment calculated by the AHP based VCM, the preferred treatment directly assessed prior to completion of the AHP based VCM, and the final treatment received.