Development and validation of a patient reported experience measure for experimental cancer medicines (PREM-ECM) and their carers (PREM-ECM-Carer)

Our aim was to develop a validated Patient Reported Experience Measure (PREM) to capture patient and carer experience during participation in experimental cancer medicine trials (ECM): called PREM-ECM.

Mixed method design, consisting of four stages. Questionnaire items were produced for both patients and carers using interviews, focus groups, and cognitive interviews with patients and carers separately. For both patient and carer PREMs, a cross-sectional questionnaire study was conducted to identify final items for inclusion using hierarchical item reduction and Rasch analysis. Questionnaire validity and reliability were assessed, including administration feasibility.

Initial interview participants suggested the need for three PREMs, two specific to patients: (i) a ‘prior’ questionnaire that captured experiences of trial introduction, screening, consenting, and early trial experience (< 6 weeks post consent); and (ii) ‘on-trial’ that captured experiences of ongoing consent and trial participation; and (iii) a PREM specific for carers. The draft 25-item ‘prior’ questionnaire was completed by 162 patients and 162 patients completed the draft 35-item ‘on-trial’ questionnaire. Hierarchical and Rasch analysis produced a 14-item ‘prior’ list and a 15-item list for ‘on-trial’. Both patient PREM’s demonstrated a good fit to the Rasch model following Bonferroni correction (X²p = 0.008). The carer 34-draft item questionnaire was completed by 102 participants. Hierarchical and Rasch analysis produced a 13-item list for PREM-ECM-Carer, with good fit to the Rasch model ( X²p = 0.62). The pilot testing demonstrated the feasibility of all the PREMs in capturing patient and caregiver experiences in routine clinical settings.

The three PREM-ECM questionnaires will be the first validated experience measures for ECM trial patients and their carers. These questionnaires may be used to assess patients’ and their carers’ experiences of ECM and enable robust comparisons across cancer trial units highlighting areas for service improvement.