Tumour response and morphological changes of acoustic neurinomas after radiosurgery

Abstract

Twenty-seven of the 1560 patients treated by radiosurgery during the period 1984-1993 had acoustic neurinomas. Four cases were excluded from this study because they had a follow-up of less than 2 years. There were 24 neurinomas treated in 23 patients as one patient had a bilateral tumour. Seven patients underwent radiosurgery for a recurrent tumour (already operated on once or twice), while it was the first treatment for 16 patients. The tumour volume ranged from 1.99 cm3 to 18.30 cm3, and the patient follow-up was from 2 to 8 years. To determine the target on CT/NMR for linear accelerator stereotactic irradiation, the Greitz-Bergström non-invasive head fixation device was used. It was again adopted for subsequent serial imaging, and for repeat radiosurgery when necessary. The total peripheral tumour dose ranged from 12 to 45 Gy. In 9 patients there was a reduction in tumour volume varying from 39 to 100%, while 14 of the neurinomas appeared stable after an average follow-up of 3 years. In one patient there was an increase in size of the tumour. Variable morphological changes were present in 66% of the neurinomas treated. Radiosurgery is indicated as an alternative to microsurgery for inoperable patients and for those who refuse surgery, for recurrent tumours, and as a post-operative complementary treatment for partially removed tumours. A gradual approach to radiosurgery, depending on tumour response, allows a greater efficacy with minimal risk. In the present series no complications were observed. Hearing was preserved at almost the same level as that prior to radiosurgery in all patients.

The efficacy of stereotactic radiosurgery in the management of Vestibular Schwannomas – a retrospective analysis

“…Any perceived volume increase is usually representative of swelling and not growth. 26,27 This was confirmed in the author's study, since for those patients demonstrating an initial volume increase, 88.9% subsequently demonstrated a reduction in TV with 68.8% having returned to the pre-treatment volume by the 12 months follow up.What is clear however is that the true significance of these changes still needs to be fully established, it may be that in the future better delineation and assessment could be made utilising Single Photon Emission Computerised Tomography (SPECT) or dynamic MR imaging in order to more fully understand aetio-pathogenesis.…”

Hearing preservation after LINAC radiosurgery and LINAC radiotherapy for vestibular schwannoma

“…In our LINAC SRT analysis, a total of 629 patients across 12 studies met our selection criteria (Supplementary Table 2) [24][25][26]28,32,[44][45][46][47][48][49][50] with an overall hearing preservation of 75.3% (Table 2). [24][25][26]28,32,[44][45][46][47][48][49][50] The average age of patients was 53.3 years (±6.8 years) with a mean follow-up period of 38.5 months (±29.7 months).…”

“…[24][25][26]28,32,[44][45][46][47][48][49][50] The average age of patients was 53.3 years (±6.8 years) with a mean follow-up period of 38.5 months (±29.7 months). The average radiation dose to the tumor margin was 36.8 Gy.…”

Stereotactic radiosurgery in the management of acoustic neuromas associated with neurofibromatosis Type 2

“…2,3,12,23,37-40,42,43,46-48 In contrast, few studies document tu-mor control rates and cranial nerve morbidity in patients who undergo radiosurgery. 9,17,25,29,34,45 To assist both patients and physicians in evaluating the risks and benefits of radiosurgery, we reviewed our experience with all NF2associated acoustic neuromas treated at our center during a 10-year interval. …”