Development and validation of an Emoji Sticker Scale from the Patient-Reported Outcome Common Terminology Criteria for Adverse Events for patients with breast cancer

Abstract

Abstract Purpose: Emojis are commonly used for daily communication and may be useful in assessing patient-reported outcomes (PROs) in breast cancer. The purpose of this study is to develop and validate an Emoji Sticker Scale (ESS) as a new PRO measurement. Methods: Eighteen original ESS items were developed from the PRO-CTCAE. In cohort one, the ESS validity and reliability were examined in patients with breast cancer, using a semi-structured five-question survey to investigate content validity. PROs with PRO-CTCAE and ESS were examined twice to determine criteria validity and test-retest reliability. In cohort two, the responsiveness of the scales were examined in patients treated with anthracycline, docetaxel, paclitaxel, and endocrine therapy. PROs with PRO-CTCAE and ESS were investigated two or three times, depending on the therapy. Results: Patients were enrolled from August 2019 to October 2020. In cohort one (n=70), most patients had no difficulties with the ESS, but 16 patients indicated that it was difficult to understand severities in the ESS. For criterion validity, Spearman rank correlation coefficients (rs) between PRO-CTCAE and ESS items were ≥0.41, except for “Decreased appetite.” For test-retest reliability, κ coefficients of the ESS were ≥0.41 for 16/18 items (88.9%). Response time was significantly shorter for the ESS than for PRO-CTCAE (p<0.001). In cohort two (n=106), score changes between PRO-CTCAE and ESS for relevant symptoms all had correlations with rs≥0.41. Conclusion Parts of the original ESS developed from PRO-CTCAE require updating. However, this study provides a comprehensive confirmation of the validity, reliability, and responsiveness of the ESS.