Management strategies for bilateral vestibular schwannomas

Treatment Analysis and Overall Survival Outcomes of Patients With Bilateral Vestibular Schwannoma

OBJECTIVES

To investigate the clinical presentation, treatment breakdown, and overall survival (OS) outcomes of patients with neurofibromatosis type 2 (NF2)-associated bilateral vestibular schwannoma (NVS).

METHODS

The 2004 to 2016 National Cancer Database was queried for patients with a diagnosis of VS. The "Laterality" code was used to stratify patients into sporadic unilateral vestibular schwannoma (UVS) and NVS.

RESULTS

Of the 33,839 patients with VS, 155 (0.46%) were coded for NVS with an average age and tumor size of 37.4 ± 20.5 years and 23.5 ± 18.2 mm. Patients underwent observation (45.3%), surgery (29.3%), and radiotherapy (20.0%), and had a 5.8% 5-year mortality rate. Compared with UVS, NVS was negatively associated with receiving surgery (40.2% versus 29.3%, p = 0.02) while watchful observation was more prevalent (30.1% versus 45.3%, p = 0.001). In NVS, undergoing surgery was associated with larger tumor size (34.5 ± 21.2 versus 17.8 ± 13.3 mm, p = 0.001) and shorter diagnosis-to-treatment time (49.1 ± 60.6 versus 87.0 ± 78.5 d, p = 0.02), radiotherapy was associated with older age (44.4 ± 18.9 versus 35.2 ± 20.6 yr, p = 0.02) and longer diagnosis-to-treatment time (85.9 ± 77.9 versus 53.9 ± 65.5 d, p = 0.04), and observation was associated with smaller tumor size (17.8 ± 15.9 versus 28.0 ± 19.2 mm, p = 0.01). Kaplan-Meier log-rank analysis demonstrated similar 10-year OS between NVS and UVS patients (p = 0.58) without factoring the earlier age of presentation. Furthermore, there were no temporal changes in presentation/management of NVS, and OS was not dependent on the received treatment (p = 0.30).

CONCLUSIONS

With younger age, larger tumors, and more conservative management, NVS's OS was not treatment-dependent and was similar to sporadic UVS, though the latter should not be interpreted as similar life expectancies due to the much earlier presentation.

Large and giant vestibular schwannomas: does cisterna magna hyperproteinorrhachia influence visual status?

BACKGROUND

Hyperproteinorrhachia associated with vestibular schwannomas (VSs) may influence visual status independent of the effect caused by raised intracranial pressure. The role of cisterna magna CSF protein levels (CMCP) in determining visual outcome in patients with large to giant vestibular schwannomas (VSs) was prospectively investigated.

METHODS

The mean CMCP levels in VSs and control group; and, levels in VSs with or without visual deterioration were compared. Spearman's rank correlation coefficient tested for relationships between CMCP level with symptom duration and tumour volume (Kawamoto's method). Vision was regarded as normal when visual acuity was >6/18; and, deteriorated when it was between 6/18 and PL negative in the worse eye. Papilloedema (n = 26)/secondary optic atrophy (n = 6) and hydrocephalus (based on Evan's ratio, mild to moderate: n = 22; none: n = 18) were also recorded. The analysis of factors predicting diminished vision was done using logistic regression analysis (p < 0.05 significant).

FINDINGS

There was a significant difference (p < 0.001) in mean CMCP levels between VS (456.3 SD 213.6 mg/dl) and control groups (96.3 SD 74.3 mg/dl). The mean CMCP levels in the VS group were also markedly higher than the ventricular mean protein levels. The CMCP levels in patients with visual diminution (<6/18 to PL negative; n = 23) was 561.4 SD 186.9 mg/dl and those without visual loss (n = 17) was 314.2 SD 160.8 mg/dl (p < 0.001). Their grade of visual diminution had a positive correlation with mean CMCP levels (p < 0.001). There was a negative correlation between total duration of symptoms and CMCP levels (p < 0.015). Logistic regression analysis using five independent factors (symptom duration, papilloedema/secondary optic atrophy, tumour volume, hydrocephalus and mean CMCP level) revealed that only CMCP level had a significant association with visual diminution.

CONCLUSION

Elevated cisternal CSF proteins may play an important role in determining visual outcome in large to giant VSs. Ventricular CSF analysis is often unable confirm the presence of VS-associated cisternal hyperproteinorrhachia. High CMCP levels may influence decision-making while instituting a permanent CSF diversion for postoperative hydrocephalus or recalcitrant pseudomeningocoele.