John, Maie A. St.

Background: Sinonasal malignancies (SNM) are rare cancers associated with poor prognosis and impaired quality of life (QOL). The 22-question Sino-Nasal Outcome Test (SNOT-22) has been used to assess QOL in patients with SNM. Objective: To determine the minimal clinically important difference (MCID) for the SNOT-22 in patients with SNM. Methods: About 264 patients with SNM were drawn from a prospective, longitudinal, multi-institutional study. SNOT-22 scores were collected at pre-treatment baseline and follow-up through 5 years post-treatment. Cronbach’s alpha was used to assess the internal consistency of the SNOT-22. Distribution-based approaches were used to estimate the MCID. Multivariable regression identified factors associated with SNOT-22 improvement exceeding the determined MCID. Results: Cronbach’s alpha was >.85. The estimated MCIDs were: 1.44 (Cohen’s effect size), 1.32 (standard error of the mean), 10.45 (1/2 of baseline standard deviation), and 3.67 (minimum detectable change). The mean MCID across methods was 4.22. Multivariable regression demonstrated higher odds of clinically meaningful improvement from baseline in patients with early-stage disease (odds ratio (OR) 3.510, P = .035), no neck irradiation (OR 11.050, P = .014), and neoadjuvant therapy (OR 16.667, P = .047). Conclusions: The SNOT-22 MCID was estimated as 4.22 in a large multi-center cohort of patients with SNM, suggesting that relatively small QOL changes are clinically relevant. When applying the MCID to the current cohort, advanced stage, treatment of neck disease, and not requiring neoadjuvant therapy were predictive of worse QOL.