Measuring female breast cancer survivors' concerns about late effects of treatment: initial development of the Concerns about Late Effects in Oncology Questionnaire (CLEO).

PURPOSE: While an increasing number of women are surviving breast cancer, survivors remain at risk of developing late effects. Late effects are long-term side effects which may emerge months to years after completing active treatment. Survivors may experience chronic worry and concern about the unpredictable and debilitating nature of late effects. This qualitative study aimed to explore the content validity of items included in the first patient-reported outcome measure (PROM) to quantify survivors' concerns about late effects: the Concerns about Late Effects in Oncology Questionnaire (CLEO).
METHOD: Items included in the CLEO were informed by a literature review and consultation with expert stakeholders. Breast cancer survivors completed "think aloud" interviews to explore the perceived acceptability, relevance, clarity, and feasibility of the CLEO. Interviews were transcribed verbatim and analyzed using framework analysis.
RESULTS: Twenty-eight participants were interviewed. Participants indicated the CLEO was acceptable, relevant to women's experiences of late effects, and easy to use and understand. Of the 55 proposed items, participants endorsed 33 items across six domains and suggested to include one additional item.
CONCLUSIONS: These findings suggest the CLEO captured concerns relevant to breast cancer survivors and provides initial validation of items for inclusion in the CLEO. The CLEO may improve communication about late effects in clinical settings and prompt future research into evidence-based interventions for survivors. Future research should assess the relevance of the CLEO items to other cancer populations. The psychometric properties of the CLEO will be evaluated in future stages of questionnaire development.