To determine the magnitude of clinically significant differences in domain scores for a quality-of-life questionnaire specific to head and neck cancer; and to demonstrate a clinically relevant method of presenting head and neck cancer–specific quality-of-life data using cutoff scores and clinical anchors.Design
Anchor-based and distribution-based techniques for determining clinically significant differences in health-related quality-of-life scores were used.Setting
University-based tertiary care hospital.Patients
A total of 421 patients with head and neck cancer enrolled in a longitudinal outcomes project.Main Outcome Measures
The Head and Neck Cancer Inventory; clinical anchor health status in the domains of speech, eating, and social disruption; and distribution-based clinically significant score differences.Results
Clinical anchor health states representing incremental levels of dysfunction were significantly correlated with domain scores for eating, speech, and social disruption. The anchor-based clinically important difference magnitudes were consistent with the values obtained using distribution-based techniques. For mean domain scores (minimum, 0; maximum, 100), differences of approximately 4, 10, and 14 or greater represented small, intermediate, and large clinically significant differences, respectively. Stratifying mean domain scores into low (0–30), intermediate (31–69), and high (70–100) categories allowed presentation of the health-related quality-of-life data in a clinically relevant format.Conclusions
This study provides benchmarks for small, intermediate, and large clinically significant changes in scores and demonstrates the presentation of health-related quality-of-life data in a clinically useful format.