Gamma Knife radiosurgery for vestibular schwannoma: clinical results at long-term follow-up in a series of 379 patients

Abstract

ObjectSince the 1990s, Gamma Knife radiosurgery (GKRS) has become the first-line treatment option for small- to medium-size vestibular schwannomas (VSs), especially in patients without mass effect–related symptoms and with functional hearing. The aim of this study was to assess the safety and efficacy of GKRS, in terms of tumor control, hearing preservation, and complications, in a series of 379 consecutive patients treated for VS.MethodsOf 523 patients treated at the authors' institution for VS between 2001 and 2010, the authors included 379 who underwent GKRS as the primary treatment. These patients were not affected by Type 2 neurofibromatosis and had clinical follow-up of at least 36 months. Clinical follow-up (mean and median 75.7 and 69.5 months, respectively) was performed for all patients, whereas audiometric and quantitative radiological follow-up examinations were obtained for only 153 and 219 patients, respectively. The patients' ages ranged from 23 to 85 years (mean 59 years). The mean tumor volume was 1.94 ± 2.2 cm3 (median 1.2 cm3, range 0.013–14.3 cm3), and the median margin dose was 13 Gy (range 11–15 Gy). Parameters considered as determinants of the clinical outcome were long-term tumor control, hearing preservation, and complications. A statistical analysis was performed to correlate clinical outcomes with the radiological features of the tumor, dose-planning parameters, and patient characteristics.ResultsControl of the tumor with GKRS was achieved in 97.1% of the patients. In 82.7% of the patients, the tumor volume had decreased at the last follow-up, with a mean relative reduction of 34.1%. The rate of complications was very low, with most consisting of a transient worsening of preexisting symptoms. Patients who had vertigo, balance disorders, or facial or trigeminal impairment usually experienced a complete or at least significant symptom relief after treatment. However, no significant improvement was observed in patients previously reporting tinnitus. The overall rate of preservation of functional hearing at the long-term follow-up was 49%; in patients with hearing classified as Gardner-Robertson (GR) Class I, this value was 71% and reached 93% among cases of GR Class I hearing in patients younger than 55 years.ConclusionsGamma Knife radiosurgery is a safe and effective treatment for VS, achieving tumor control in 97.1% of cases and resulting in a very low morbidity rate. Younger GR Class I patients had a significantly higher probability of retaining functional hearing even at the 10-year follow-up; for this reason, the time between symptom onset, diagnosis, and treatment should be shortened to achieve better outcomes in functional hearing preservation.

Gamma Knife radiosurgery for glomus tumors: Long‐term results in a series of 30 patients

“…Despite a good clinical outcome, new CNs deficit have been reported even after Gamma Knife radiosurgery for glomus tumor. 44 A prescription dose ≤13 Gy showed low risk of vertigo, facial impairment, and trigeminal neuralgia after Gamma Knife radiosurgery for vestibular schwannomas, and the probability of developing trigeminal neuralgia was strictly related to the volume of brainstem exposed to a dose of 10 Gy. 32,40,41 Other less frequent reported cranial neuropathies after Gamma Knife radiosurgery are trigeminal neuralgia and facial weakness.…”

Stereotactic radiosurgery vs. fractionated radiotherapy for tumor control in vestibular schwannoma patients: a systematic review

“…The initial review could discard 997 records as not relevant to the topic or as inadequate regarding cohort size or follow-up time, and after reference cross-check 98 records were reviewed according to a systematic review protocol. After the second review round a final 19 records were found to fulfill all inclusion criteria [2, 6, 10, 15, 17, 19, 22, 24, 28, 29, 33, 36, 39, 44, 48, 50, 52, 53, 56]. No randomized studies (S1) were identified on the subject.…”

Radiation therapy for older patients with brain tumors

“…In another study of 100 patients aged 65 or older (median age 71 years) treated with FSRT (56.5 Gy), hypofractionated stereotactic RT (36.3 Gy in 5–7 fractions) or single-fraction SRS (17.6 Gy), Kaul et al [123] observed a 5-year local control of 91.1%, with no grade 2 or 3 neurological toxicity. No study have specifically addressed the outcome of RT in older patients with either secreting or nonsecreting pituitary adenomas, and acoustic neuromas; however, data reported in large retrospective studies and systematic reviews show similar local control and toxicity between young and older patients after either SRS or FSRT [124–142]. Single-fractions doses of 13–16 Gy and 20–28 Gy are usually employed for non-functioning and secreting pituitary adenomas [124, 125, 129–134], respectively, and of 12–14 Gy for acoustic neuromas [135, 137, 139–142].…”

“…No study have specifically addressed the outcome of RT in older patients with either secreting or nonsecreting pituitary adenomas, and acoustic neuromas; however, data reported in large retrospective studies and systematic reviews show similar local control and toxicity between young and older patients after either SRS or FSRT [124–142]. Single-fractions doses of 13–16 Gy and 20–28 Gy are usually employed for non-functioning and secreting pituitary adenomas [124, 125, 129–134], respectively, and of 12–14 Gy for acoustic neuromas [135, 137, 139–142]. Hypofractionated RT and FSRT using doses of 21–25 Gy in 3–5 fractions and 45–54 Gy in 25–30 daily fractions of 1.8 Gy, respectively, are frequently employed for large tumors involving the optic pathway or compressing the brainstem [126–128, 133–136, 138].…”