Background: The minimal clinically important difference (MCID) is defined as the smallest difference in quality of life (QOL) that patients perceive as beneficial and that mandates a change in management. We aimed to determine the MCID among patients with oral cavity and oropharyngeal cancer and to identify domains that are significantly affected during treatment.
Methods: The cohort consisted of 1,011 patients analyzed by a metaanalysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. MCID values for the University of Washington Quality of Life Questionnaire (UW-QOLQ) and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC C-30) and Head and Neck-35 questionnaires were calculated by using the distribution-based method.
Results: The mean MCID for Global QOL was 13.07 points for the UW-QOLQ and 9.43 in the EORTC C-30 questionnaire. High consistency in the MCID values was found between the two questionnaires examined. Heat map analysis indicated a clinically significant improvement in head and neck-associated domains and in domains associated with general cancer treatment 1 year or more after treatment relative to 3 months after treatment (p < 0.001 and p = 0.016, respectively). In contrast, improvement in general and functional domains was not evident 1 year or more after treatment (p = 0.69).
Conclusions: This study suggests benchmark values for MCID and variation in QOL scores of oral and oropharyngeal cancer patients after treatment. Improvement in head and neck- and general cancer-associated domains may not be translated into a general and functional improvement during the first year of recovery.