Objective: To translate and validate the 'Sinhala' language version of the European Organization for Research and Treatment of Cancer head-and-neck cancer-specific health-related quality-of-life questionnaire module, the QLQ-H&N35, for use in Sri Lanka.
Methods: Psychometric testing assessed the hypothesized scale structure, scale reliability, construct validity and acceptability of the translated version of the QLQ-H&N35 in a consecutive series of 196 newly diagnosed head-and-neck cancer patients, recruited from tertiary-care oncology treatment centres in Sri Lanka.
Results: Compliance was high (97.5%), although nearly 40% of patients required assistance with completion of the questionnaire. Twenty-four sexually inactive patients declined to answer one or both items of the sexuality scale. Multi-trait scaling confirmed the overall scale structure, with good item-convergent (100%) and -discriminant (93.8%) validity, and scaling success (86.8%) rates. Cronbach's alpha coefficients exceeded 0.70 for all scales, except problems with sexuality (0.60) and problems with senses (0.61), which also evidenced a lower scaling success rate (50%). Confirmation of construct validity included satisfactory results for inter-scale correlations and known-groups comparisons for most scales; most correlations were statistically significant (p<0.01), with conceptually related scales showing relatively higher correlation. Most scale scores were able to discriminate clearly between pre- and current treatment patients.
Conclusions: Results of the study provide strong support for the psychometric robustness of the 'Sinhala' version of the QLQ-H&N35. It may be advisable to interpret the two items assessing sensory problems separately, and to elicit information on sexuality from only those who are sexually active.