Long-term Treatment Response and Patient Outcomes for Vestibular Schwannoma Patients Treated with Hypofractionated Stereotactic Radiotherapy

Abstract

PurposeThe aim of this study is to evaluate long-term treatment outcome and toxicities among vestibular schwannoma (VS) patients treated with hypofractionated stereotactic radiotherapy (HSRT).Methods383 patients with unilateral VS treated with HSRT (25 Gy, five fractions) between 1995 and 2007 were retrospectively reviewed. Treatment failure was defined as requiring salvage microsurgery. Posttreatment new/progressive clinical symptoms or increases in baseline tumor volume (BTV) due to treatment effect or progression were noted. Symptom outcomes were reported as baseline and posttreatment ± improvement, respectively. Symptoms were grouped by cranial nerve (CN) VII or CNVIII. Audiometry was assessed baseline and posttreatment hearing. Patients were grouped as having greater than serviceable hearing [Gardner Robertson (GR) score 1–2] or less than non-serviceable hearing (GR score 3–5) by audiometry.ResultsMedian follow-up was 72.0 months. Nine (2.3%) experienced treatment failure. At last follow-up, 74 (19.3%) had new/progressive symptoms and were categorized as radiologic non-responders, whereas 300 (78.3%) had no tumor progression and were grouped as radiologic responders. Average pretreatment BTV for treatment failures, radiologic non-responders, and radiologic responders was 2.11, 0.44, and 1.87 cm3, respectively. Pretreatment CNVII and CNVIII symptoms were present in 9.4 and 93.4% of patients, respectively. Eight (24%) with pre-HSRT CNVII and 37 (10%) with pre-HSRT CNVIII symptoms recovered CN function post-HSRT. Thirty-five (9%) and 36 (9.4%) experienced new CNVII and CNVIII deficit, respectively, after HSRT. Of these, 20 (57%) and 18 (50%) recovered CNVII and CNVIII function, respectively, after HSRT. Evaluable audiograms were available in 199 patients. At baseline and at last follow-up, 65.8 and 36.2% had serviceable hearing, respectively. Fifty-one percent had preservation of serviceable hearing at last follow-up.ConclusionTreatment of VS with HSRT is effective with treatment success in 97.7% and an acceptable toxicity profile. Less than one-third of patients experience any new CNVII or CNVIII deficit posttreatment. Greater than 50% of patients with serviceable hearing at baseline maintained hearing function. Improved methods to differentiate treatment effect and tumor progression are needed.

Long‐term clinical outcomes of stereotactic radiosurgery and hypofractionated stereotactic radiotherapy using the CyberKnife® robotic radiosurgery system for vestibular schwannoma

“…In the current study, the median time to progression was 42 months without any treatment failure after 8 years. This is consistent with the results of long‐term studies that showed that late treatment failure is uncommon after SRS/SRT 18,29 …”

“…This is consistent with the results of long-term studies that showed that late treatment failure is uncommon after SRS/SRT. 18,29 In the current study, Koos grade III/IV was the only factor associated with disease progression. Koos grade III is defined as extrameatal tumors in contact with the brainstem, whereas Koos grade IV is an extrameatal tumor that compresses the brainstem.…”

Fractionated Proton Radiation Therapy and Hearing Preservation for Vestibular Schwannoma: Preliminary Analysis of a Prospective Phase 2 Clinical Trial

“…Finally, at a median follow-up of 4 years, hearing loss tended to plateau at 1 year, earlier than other long-term series. [42][43][44] Proton therapy may have a greater biological effect on normal tissues, which could contribute to greater hearing loss earlier than anticipated.…”

Stereotactic radiotherapy for presumed oculomotor nerve schwannoma masquerading as “ophthalmoplegic migraine”

“…The outcome reflected similar favourable rates of control (80%-90%) in vestibular schwannoma treated with hypofractionated radiotherapy. 8,9 Third, our case suggests that control of inflammation within an oculomotor nerve schwannoma may be more important than reduction of tumour size. Finally, our case highlights that inaccurate medical terminology can have adverse and long-term affects on patient care.…”