FRACTIONATED STEREOTACTIC RADIOTHERAPY FOR VESTIBULAR SCHWANNOMA: FIVE-YEAR OUTCOMES FROM A SINGLE INSTITUTION

Fractionated stereotactic RT (FSRT) with achievable cochlear dose constraints was favoured over stereotactic radiosurgery (SRS) to preserve hearing. This retrospective review studied the treatment outcome in all patients with unilateral benign VS treated with FSRT between 2015–2025 at a single centre. The primary endpoint was tumour control; secondary endpoints were serviceable hearing preservation, toxicity and pseudoprogression. Twenty‑eight patients (median age 61 y, range 30–80) were included; most tumours were Koos IV (82.1%), half had prior surgery. Median maximal diameter, GTV and PTV were 2.7 cm, 3.94 cm³ and 7.85 cm³ respectively; 78.6% received 45 G­y in 25 fractions and the remainder 41.4–43.2 Gy in 23–24 fractions. Median follow-up was 45.5 months (range 12-107). Tumour control rate was 88.6% at 2 years and median was not reached at 5 years. Baseline serviceable hearing was correlated with smaller tumours (median diameter 1.40 vs 3.00 cm, GTV 1.55 vs 6.55 cm³, both p≤0.015). Among 7 patients with baseline serviceable hearing, 2‑year serviceable‑hearing preservation rate was 42.9% (3/7), although estimates are imprecise given the small n. Patients with progression (n=3) or pseudoprogression (n=3) had larger baseline tumours than those with stable disease or partial response (3.2 vs 2.4 cm, p=0.022). Other RT‑related complications were uncommon (<10% each), all were Grade 1-2. Overall, FSRT for predominantly Koos IV VS achieved high tumour control with low pseudoprogression rates but modest hearing preservation only, hence radiosurgery or hypofractionated stereotactic radiotherapy might be reasonable alternatives for resource preservation.