Cross-cultural adaptation and validation of a self-reporting tool to assess health-related quality of life for Egyptians with extremity bone sarcomas in childhood or adolescence

Validated self-reporting tools are required to evaluate the functional outcome and health-related quality of life (HRQOL) for those who had extremity bone sarcomas in their childhood or adolescence. Our study pursued cross-cultural adaptation and validation of the pediatric Toronto Extremity Salvage Score (pTESS) and Toronto Extremity Salvage Score (TESS) to assess the functional outcome for Egyptian children and adult survivors following surgeries of extremity bone sarcomas. In the modified versions of pTESS and TESS, mental domains were added to allow the evaluation of HRQOL using a specific instrument for childhood bone cancer. The internal consistency and test-retest reliability of the studied forms were assessed with Cronbach's alpha and Intra-class coefficients (ICC), respectively. For convergent validity, correlations between scores of the generic Pediatric Quality of Life Inventory (PedsQL 4.0) and pTESS /TESS scores were reported. Factor Analysis was feasible for pTESS-leg; due to the insufficient samples, only the average inter-item correlation coefficients were reported for the remaining versions. Out of 233 participants, 134 responded to pTESS-leg, 53 to TESS-leg, 36 to pTESS-arm, and only 10 to TESS-arm. All versions showed excellent internal consistency (Cronbach's alpha >0.9), good test-retest reliability (ICC >0.8), moderate to strong correlations with PedsQL, and acceptable average inter-item correlation coefficients (≥0.3). Three factors were extracted for the pTESS-leg, in which all mental items were loaded on one separate factor with factor loadings exceeding 0.4. Active chemotherapy, less than one year from primary surgery, or tibial tumors were associated with significantly inferior pTESS/TESS scores in the lower extremity group. The Egyptian pTESS and TESS are valid and reliable self-reporting tools for assessing the functional outcome following surgeries for extremity bone sarcomas. The modified pTESS and TESS versions, which include additional mental domains, enabled the assessment of the overall health status of our population. Future studies should include a larger sample size and evaluate the ability of pTESS/TESS to track progress over time.