Rates and predictors of follow-up loss for sporadic vestibular schwannomas undergoing imaging surveillance

Introduction: Imaging surveillance is a management option for patients with small vestibular schwannomas (VS). Recent randomized trial data demonstrates similar quality-of-life outcomes between patients undergoing a “wait and scan” approach versus upfront stereotactic radiosurgery (SRS). However, imaging surveillance is dependent on patient adherence to follow-up. This study aimed to identify rates and predictors of follow-up loss for patients undergoing imaging surveillance of sporadic VS.

Methods: A single center study was conducted including all patients from 2013 – 2018 who underwent imaging surveillance of a sporadic VS. Patient demographic and clinical data were obtained retrospectively from the electronic medical record. Outcomes of interest included: 1) complete loss to follow-up unrelated to death as well as 2) inconsistent imaging surveillance for patients who did follow-up. Patients were censored at the time of first treatment, death, or last available MRI. Logistic regression analyses were conducted to evaluate factors associated with loss of follow-up.

Results: Over a 6-year study period, 289 patients underwent upfront imaging surveillance of a sporadic VS At the time of censoring, 115 patients (39.8%) received treatment, 167 (57.8%) were recommended continued follow-up, and 7 (2.4%) had died. In total, 75 patients (26%) were lost to follow-up prior to first treatment or death. For patients who were not lost to follow-up, 18.9% (31/164) demonstrated inconsistencies with imaging surveillance outside the provider recommended timeframe. Multivariate logistic regression identified out-of-state location (OR 2.8, 95%CI 1.5-5.3, p=0.0016), decreased tumor diameter (unit OR per 1 cm increase in diameter: 0.9, 95% 0.84-0.95, p=0.0006), and unemployed or disabled status (OR 3.4, 95%CI 1.1-10.5, p=0.03) to be significantly associated with being lost to follow-up.

Conclusion : Patients undergoing imaging surveillance of vestibular schwannomas within the United States are frequently lost to follow-up with about 26% of the cohort being lost to follow-up at our institution without evidence of external follow-up. Both tumor and socioeconomic factors such as patient location, tumor size, and employment status may contribute to rates of follow-up.