Exploratory estimation of minimal clinically important deterioration in oral and swallowing function after oral cancer treatment: A prospective observational study.

OBJECTIVE

Oral cancer treatment frequently results in postoperative oral dysfunction, which may contribute to dysphagia, malnutrition, and impaired quality of life. Although objective and patient-reported oral/swallowing function measures are used in clinical practice, the minimal clinically important differences (MCIDs) corresponding to patient-perceived deterioration remain unclear. This study aimed to determine the MCIDs of objective and patient-reported oral/swallowing function measures associated with the oral health-related quality of life in patients with oral cancer.

METHODS

This study included patients treated by an oral and maxillofacial surgery team at a tertiary university hospital from September 30, 2019, to December 31, 2025, and followed up at the end of the primary treatment. A total of 146 patients were evaluated before treatment and at discharge after primary therapy. Six oral function measures and the Geriatric Oral Health Assessment Index (GOHAI) were assessed, and anchor- and distribution-based methods were used to estimate the MCIDs.

RESULTS

The total GOHAI scores decreased significantly. Multivariate analyses demonstrated that postoperative tongue pressure and EAT-10 scores were independently associated with GOHAI scores. Using a 3-point change in GOHAI as the primary anchor, estimated MCIDs were 0.5 for microorganisms, -3.05 for oral dryness, -321.6 N for occlusal force, -6.05 kPa for tongue pressure, -26.5 mg/dL for masticatory function, and 7.5 points for EAT-10. Distribution-based approaches yielded higher threshold values.

CONCLUSION

These findings provide exploratory reference thresholds for interpreting clinically meaningful changes in oral and swallowing functions after oral cancer treatment and underscore the importance of MCID-based evaluation beyond statistical significance alone.