Identifying at diagnosis the vestibular schwannomas at low risk of growth in a long‐term retrospective cohort

Objectives Identification at time of diagnosis of those vestibular schwannomas that will not grow. Design Retrospective cohort study of consecutive patients diagnosed with a sporadic vestibular schwannoma that were entered in the wait‐and‐scan protocol. Setting Academic referral centre. Participants The study group contained 155 patients with a sporadic vestibular schwannoma first seen in the full 8‐year period 2000–2007: continual wait‐and‐scan ( n = 89) and initial wait‐and‐scan until intervention ( n = 66). Main outcome measures Tumour growth, defined as more than 2 mm linear difference in any plane between the diagnostic MRI ‐scan and the last available scan, was related to clinical parameters at diagnosis: localisation of the tumour (solely intracanalicular versus cisternal extension), sudden sensorineural hearing loss, sensorineural hearing loss longer than 2 years and vertigo/instability. Results Hearing loss longer than 2 years and an entirely intracanalicular localisation were associated with no tumour growth by univariate and multivariate Cox analysis. Combining both factors at time of diagnosis resulted in a group with low risk of growth ( n = 36, median follow‐up of 6.2 years) with a Hazard Ratio for growth of 0.37 (95% CI , 0.19–0.69). This subgroup is about 25% of the wait‐and‐scan population. Thirty‐one percent showed growth, while in the remaining higher risk group of 119 patients 62% showed growth. For the growing schwannomas, the median time for growth becoming manifest is 1.9 years after diagnostic MRI . Conclusions In this study on vestibular schwannoma patients that start in a wait‐and‐scan protocol, about a quarter may be set apart having a low risk for growth. These patients at diagnosis combine a history of hearing loss longer than 2 years and a fully intracanalicular schwannoma. They seem to be not needed yearly MRI checks.