Clinical and inflammatory factors associated with the extent of resection in primary, sporadic vestibular schwannomas: A retrospective study.

Background: The extent of resection (EOR) is known to impact recurrence free survival in vestibular schwannomas (VS). Identifying predictive factors for complete resection may direct treatment decisions in the future. In recent years there is increasing evidence for the involvement of inflammatory processes in the development and growth of VS. It is currently unclear whether inflammatory changes may also play a role in the extent of resection in VS.

Methods: In this retrospective study, we analyzed clinical data, tumor extension, cystic characteristics and immunohistochemical markers for inflammation (CD68, CD163, CD3, CD8) and proliferation (MIB-1) as potential factors influencing the EOR in 1007 surgically treated primary sporadic VS. With CART-determined specific cut-offs for each inflammation marker, a common inflammatory score from 0 to 2 was determined. Univariate and multivariate analyses were performed for the EOR.

Results: Total resection was achieved in 86.5% of cases. Incomplete resection was associated with advanced age (p = 0.0002), larger tumor size (p < 0.0001) and cystic characteristics on preoperative imaging (p < 0.0001). Increased expression of CD163, CD68 and CD3 (p < 0.0001, p = 0.0015 and p = 0.0024 respectively) was associated with partial tumor resection (PR). CD8 was significant when its CART-determined cut-off was considered (p = 0.0032). A higher inflammatory score was significantly connected to partial resection (p < 0.0001). In the multivariate analysis, larger size (p < 0.0001), older age (p = 0.0051), cystic characteristics (p = 0.0005) and higher CD68 expression (p = 0.0341) were independently significant factors for partial resection.

Conclusions: Advanced age, greater tumor extension, cystic growth and higher infiltration with macrophages are independent factors for a less radical extent of resection.