This study aims to translate the BREAST-Q into Malay and validate it in breast cancer patients undergoing surgery. The English BREAST-Q was translated to Malay using the back-translation method. A total of 144 newly diagnosed breast cancer patients were sampled conveniently between December 2015 and November 2016. Test-retest was done after two to three weeks. Data were analyzed using SPSS and AMOS software. Content experts agreed the items in the Malay BREAST-Q were measuring the constructs appropriately. Internal consistencies were good for all items in each subscale (Cronbach's alpha = 0.83-0.95). The highest inter-item correlation for each item with at least one other item in the construct ranged from 0.47 to 0.90. The lowest corrected item-total correlation values ranged from 0.47 to 0.72. The test-retest analysis showed good reproducibility (intraclass correlation coefficient = 0.71-0.98). In exploratory factor analysis, the Kaiser-Meyer-Olkin values were excellent in all four subscales (0.76, 0.92, 0.91, and 0.86). For all subscales, the number of factors extracted cumulatively explained more than 50% of the variance. The Malay BREAST-Q demonstrated good reliability, face validity, content validity, and construct validity.
Keywords: BREAST-Q; back-translation; breast cancer surgery; cross-cultural adaptation; reliability; validity.