Translation, Cross-Cultural Adaptation, Reliability and Construct Validity of the FACT- EGFRI-18 Quality of Life Instrument from English into Portuguese

Introduction: Adverse epidermal growth factor receptor (EGFR) dermatological events affect many patients and can impair the patient’s quality of life (QoL), leading to dose reduction or discontinuation of therapy. Objective: To carry out the translation, cross-cultural adaptation, reliability and validity of the Functional Evaluation of Cancer Therapy - Epidermal Growth Factor Receptor Inhibitor 18 (FACT-EGFRI-18) to be utilized in Portuguese. Method: Study to evaluate the cross-cultural adaptation, reliability and construct validation of the FACT-EGFRI-18 translated into Portuguese. To evaluate cross-cultural adaptation, semantic analysis was performed by ten patients and content analysis by experts. Reliability was assessed by internal consistency analysis using Cronbach’s alpha coefficient. Construct validity was determined by the correlation between the translated FACT-EGFRI-18 and the Dermatology Life Quality Index (DLQI) answered by 30 participants with cancer undergoing treatment with EGFR. A descriptive analysis of the study population was performed and Cronbach’s alpha coefficient was calculated to determine the internal consistency of the Portuguese version of the FACTEGFRI- 18 and Pearson’s demonstration coefficient was applied to determine the transparency between the questionnaires. ANOVA test was performed to compare the mean FACT-EGFRI-18 score according to demographic variables. Results: The semantic evaluation showed that all the participants understood the items of the translated questionnaire, which revealed strong internal consistency (Cronbach’s alpha = 0.89) and validity (Pearson's correlation = 0.66). Conclusion: The FACT-EGFRI-18 was easily understood by the patients and the results support its reliability and validity.