[Cultural adaptation and psychometric validation of the health-related quality of life questionnaire EORTC QLQ STO-22 for patients with gastric cancer in Peru].

OBJECTIVE: To validate the health-related quality of life questionnaire EORTC QLQ STO-22 for patients with gastric cancer in Peru, evaluating cultural and psychometric characteristics. MATERIALS AND METHODS: The first phase consisted in measure the content and appearance validity. In the second phase, the questionnaire was applied to patients diagnosed with gastric cancer and the internal consistency, test-retest reliability, convergent validity, discriminant validity and criterion validity was determined. RESULTS: After performing the content and appearance validity the questions/items 31 and 39 were changed. The global Cronbach's I± was 0.90 and I± coefficients greater than 0.7 in the multi-item subscales was obtained. The test-retest reliability showed an overall correlation of 0.924. When analyzing the convergent and discriminant validity, the values of Pearson's "r" were higher between an item and its own subscale, than the same item with other multi-item sub-scales. The criterion validity of the EORTC QLQ STO-22 compared with the EORTC QLQ C-30 showed a positive correlation of 0.727 with items evaluating symptomatology, and a negative correlation of -0.587 when comparing with functional status items, both statistically significant. CONCLUSION: The modified questionnaire EORTC QLQ STO-22 meets the reliability and validity criteria for assessing the quality of life in patients with gastric cancer in Peru.