Abstract
BACKGROUND: With earlier prostate cancer (PCa) diagnosis and increased survivorship, post-treatment quality of life (QoL) has become increasingly important. The Expanded Prostate Cancer Index Composite (EPIC) is a widely adopted QoL instrument for PCa. We aimed to create a Punjabi version of EPIC to further research in the Punjabi-speaking population. METHODS: A prototype of the Punjabi version of EPIC was created by forward-backward translations and revision. After concluding the cultural adaptation phase by interviewing 15 participants, a pilot version was created. Validation of the pilot version was performed by having 72 participants complete the Punjabi EPIC and another commonly used QoL instrument, the EORTC QLQ-c30, twice within a 4-week period. Test retest reliability (Pearson's correlations and difference distribution) and internal consistency (Cronbach's alpha) were measured using SAS version 9.4. RESULTS: Modifications were needed for the prototype Punjabi version after forward-backward translations. Cultural adaptation has highlighted a few issues including syntax and terminology. Test-retest reliability of the Urinary, Bowel, Sexual and Hormone domains were 0.88, 0.91, 0.91, and 0.95, respectively, and subscale correlations ranged from 0.75 to 0.93. Internal consistency for domains and subscales was good except for Sexual Domain. Performance of EPIC is comparable, and in some cases, slightly better than validated Punjabi version of EORTC QLQ-C30. CONCLUSIONS: The EPIC questionnaire was successfully translated into Punjabi and was culturally adapted. The resultant Punjabi version has high reliability and validity and will be an important tool for QoL research in the Punjabi population. EPIC was successfully translated, culturally adapted, and validated with high reliability and validity into Punjabi. It will be a valuable QoL tool for physicians in clinical and research settings, and for patients in decision-making.