Adjunctive Gamma Knife Surgery or Wait and Scan Policy After Optimal Resection of Large Vestibular Schwannomas: Clinical and Radiologic Outcomes.

OBJECTIVES

Patients with large vestibular schwannomas (VSs) will require surgical treatment owing to the potential consequences of long tract and cranial nerve compression. We assessed the long-term clinical and radiologic outcomes of patients harboring large VSs treated with a facial nerve (FN)-sparing technique.

METHODS

We performed a single-center retrospective cohort study of 169 consecutive large VSs treated surgically from January 2003 to May 2015. The postoperative volume of the tumor residue was assessed using thin-slice magnetic resonance imaging 6 months after surgery. Postoperatively, the patients were allocated to a wait and rescan (W&reS) or an upfront gamma knife surgery (GKS) policy.

RESULTS

At the last follow-up examination, FN function was good (House-Brackmann grade I or II) in 84% of the patients. Of the 169 patients, 11% had undergone gross total resection, 59% near total, 21% subtotal, and 9% partial resection. In the 143 patients without gross total resection, the overall median tumor residue volume was 0.39 cm3. Of these 143 patients, 66 had been allocated to the W&reS policy and 77 to upfront GKS. Overall tumor control was achieved in 83% of cases, with a mean follow-up of 62 months. Of the 27 growing residues, 17 required salvage treatment (11% failure rate). The 1-, 5-, and 7-year progression-free survival rate was 95%, 82%, and 76% in the W&reS group and 99%, 81%, and 78% in the GKS group, respectively (P = 0.57).

CONCLUSIONS

Functional nerve-sparing resection provides satisfactory FN preservation. The low probability of long-term regrowth of small remnants is an argument for a W&reS protocol. GKS is a legitimate option for salvage treatment.