Applying Conjoint Analysis Methodology to Oncology Symptom Science
A major barrier to conducting clinical research trials is recruitment and retention. Simply put, if we are unable to recruit patients to clinical trials testing new treatments for various diseases, then we will not be able to truly determine whether the new treatments actually work to prevent or treat disease. One strategy to potentially increase recruitment and retention of patients to clinical trials is to design trials that contain characteristics that are appealing to the population of interest.
How can we do that?
In market research, companies employ conjoint analysis methodology to understand customer preferences for different features of various products or concepts. In a conjoint analysis, participants are asked to select various characteristics (attributes) and associated values (levels) from several experimentally designed scenarios. The main outputs of a conjoint analysis experiment are how much respondents preferred each level (part-worth utility score) and how much the attributes influenced their selection of particular products or concepts (relative importance). With these data, companies can answer the question of which products or services respondents value the most and what factors drove respondents’ decisions.
The same logic can be applied to clinical trials, which often contain several design components.
Barriers related to the recruitment and retention of study participants are also present in the field of oncology symptom science.
As an example, chemotherapy-induced peripheral neuropathy occurs in up to almost 70% of people receiving neurotoxic chemotherapy (e.g., chemotherapies common to the treatment of breast, colorectal, and gynecological cancers) and is characterized by numbness, tingling, and pain in the hands and feet. There are no known ways to prevent chemotherapy-induced peripheral neuropathy. Recruitment to chemotherapy-induced peripheral neuropathy prevention clinical trials is challenging because it is difficult to identify and enroll patients between the time of diagnosis and the time of chemotherapy initiation.
To begin to understand how patients may come to decisions surrounding chemotherapy-induced peripheral neuropathy prevention clinical trial participation, we conducted a mixed methods study to determine participant preferences for chemotherapy-induced peripheral neuropathy prevention clinical trial factors.
We interviewed 20 adults who were beginning chemotherapy known to cause chemotherapy-induced peripheral neuropathy to obtain their feedback on attributes and associated levels of common design components of chemotherapy-induced peripheral neuropathy prevention clinical trials.
After several rounds of interviews, the final attributes that would be entered into an adaptive-choice-based conjoint analysis included, 1) type of new treatment for neuropathy, 2) length of study visits, 3) how to complete surveys for the study, 4) type of clinical tests for the study, 5) timing of follow-up study visits after the completion of chemotherapy, 6) when to begin the new treatment for neuropathy, 7) and reimbursement for study participation. After the interviews, an additional 88 patients beginning chemotherapy known to cause chemotherapy—induced peripheral neuropathy completed an adaptive choice-based conjoint analysis survey (Sawtooth Software, Inc; Provo, UT) that incorporated the finalized attributes and associated levels. During the survey, participants were presented with repeated tournament tasks, which consisted of three different clinical trial scenarios with varying attributes and associated levels. Participants selected the trial they most wanted to participate in and the tournament tasks continued until a final “winning” clinical trial was identified. Part-worth utility scores were assigned to each level using Hierarchical Bayes Estimation and relative importance scores were calculated for each attribute.
Study results revealed that the attributes that were most important to participants included the type of treatment and length of study visits.
The winning chemotherapy-induced peripheral neuropathy prevention clinical trial included factors such as, 1) non-medicine treatment, 2) beginning the new treatment for neuropathy after experiencing CIPN, 3) email surveys, 4) assessments that include surveys and clinical exams of arms and legs, 5) under 30 minute study visits, 6) $50 per week reimbursement, and 7) 1-month post chemotherapy follow up study visits.
To our knowledge, this study was among the first to implement conjoint analysis methodology for oncology symptom science clinical trials. Our results reveal several clinical trial factors that investigators may attempt to integrate into future chemotherapy-induced peripheral neuropathy prevention clinical trials to determine if such factors increase participant recruitment and retention. Investigators may apply conjoint analysis methodology to better understand how patients’ come to a decision surrounding clinical trial participation in other diseases and symptoms.