Effect of Extent of Resection and Adjuvant Radiation on Recurrence of BRAF versus β-Catenin-Mutated Craniopharyngioma: A Single Institutional Case Series.

Objectives: The two histologic subtypes of craniopharyngiomas (CPs), papillary and adamantinomatous, harbor mutually exclusive mutations of BRAF V600E and CTNNB1, respectively. Studies suggest that subtotal resection (STR) plus adjuvant radiation therapy (XRT) may result in similar progression-free survival (PFS) as gross total resection (GTR). We hypothesized that STR ± XRT and GTR result in similar PFS for both BRAF and β-catenin-mutated CPs.

Design: Patients who were surgically treated for a primary CP between 2001 and 2023 at a single institution were included. Immunohistochemical studies were performed retrospectively using BRAF and β-catenin antibodies. Patients with missing immunohistochemistry (IHC) diagnosis were excluded. Differences in PFS for STR ± XRT and GTR groups were assessed with a log-rank test, stratified by BRAF and β-catenin IHC status.

Results: A total of 77 patients with CP were screened. IHC data were available for 50 patients; 20 had a BRAF mutation, and 30 had a β-catenin mutation. Among BRAF patients, 11 underwent GTR; 9 had STR, and 5 had adjuvant XRT. Among β-catenin patients, 14 underwent GTR; 16 had STR, and 6 had adjuvant XRT. For BRAF patients with GTR, the median PFS was not reached; for BRAF patients with STR ± XRT, the median PFS was 150 days ( p  < 0.01, log-rank test). For β-catenin patients with GTR, the median PFS was 1,813 days; for β-catenin patients with STR ± XRT, the median PFS was not reached ( p  = 0.80, log-tank test).

Conclusions: Both GTR and STR ± XRT seemed to offer similar PFS outcomes only for patients with β-catenin-mutated CP. For patients with BRAF-mutated CP, a greater extent of resection was significantly associated with prolonged PFS.