RESUMEN
OBJECTIVES: McGill Quality of Life Questionnaire (MQOL) is an instrument specifically designed to evaluate quality of life (QOL) in patients with advanced diseases. The primary objective of this study was to translate this questionnaire into Persian and assess its reliability and validity in Iranian patients suffering from an advanced cancer. The report also includes the correlations between patients' characteristics and their QOL scores. METHODS: MQOL was translated into Persian using a forward-backward method and administered to 62 patients with cancer at two hospitals in Tehran. Statistical analysis was performed to test reliability and validity of the questionnaire and to assess relationships between patients' characteristics and MQOL scores. RESULTS: In general, MQOL-Persian is a valid and reliable questionnaire to assess QOL in Iranian patients with advanced cancer. Test-retest reliability of the whole questionnaire is highly favorable for a questionnaire of this type (Pearson correlation = 0.87). Except for the existential subscale, all MQOL scores are internally consistent. There was no significant correlation between MQOL scores and patients' extent of knowledge about their disease. CONCLUSION: The Persian version of MQOL is, for the most part, a valid, reliable instrument in this setting. Because of cultural differences, the existential subscale may require adaptation. Further studies are needed to explore other aspects of QOL in Iranian patients with cancer.