Long-Term Tumor Control Rates Following Gamma Knife Radiosurgery for Acoustic Neuroma

Tucker, Douglass W.; Gogia, Angad S.; Donoho, Daniel A.; Yim, Benjamin; Yu, Cheng; Fredrickson, Vance L; Chang, Eric L.; Freidman, Rick A.; Zada, Gabriel; Giannotta, Steven L.

doi:10.1016/j.wneu.2018.11.009

Cited by 17 publications

(11 citation statements)

References 25 publications

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“…As above, that close imaging and clinical assessment is required, it is also important to carefully consult with patients as to give neither false alarms nor false reassurance. There is a difference between post-SRS growth, which is well recognised and reported [7][8][9][10][11][12]15] and delayed regrowth following good response that is described here. This is not the usual VS behaviour; it can cause initial concerns to the treating doctor and the patient and will need to be recognised and thoroughly explained to the patient.…”

Section: Clinical Implications and Long-term Imagingmentioning

confidence: 60%

“…We do recognise that the post-SRS growing patterns have been well examined in the literature [7][8][9][10][11][12]15], showing that post-SRS growth is not uncommon and not, usually, of major concern. Indeed, previous study has shown 14% of VS showing enlargement following SRS [15], with most of these schwannomas not needing any further treatment; such initial growth has been linked to post-SRS inflammation/ oedema [7][8][9][10][11]. However, here we show good initial response and delayed re-growth, which introduces a completely different concept.…”

Section: Main Findingsmentioning

confidence: 96%

“…The primary diagnostic imaging tool is Magnetic Resonance Imaging (MRI), and is also used in the surveillance of small VS [2,3]. In larger or growing VS, microsurgical resection or Stereotactic Radiosurgery (SRS), delivering high-dose radiation to a precise location, may be required [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Long-term growth patterns of vestibular schwannomas after stereotactic radiotherapy: delayed re-growth

Conlan

Kontorinis

2022

Eur Arch Otorhinolaryngol

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Purpose To determine the long-term outcomes of patients with vestibular schwannomas (VS) after stereotactic radiosurgery (SRS) who experience delayed tumour regrowth. Methods We carried out a retrospective case series in tertiary university settings. We included patients with VS with initial response to SRS and delayed regrowth, assessing a database of 735 patients with VS and 159 patients who had SRS as sole treatment. Following SRS, all patients had clinical follow-up and serial magnetic resonance imaging (MRI). We documented the post-SRS clinical assessment, pre- and post-SRS VS size as per MRI in predetermined time periods, response to treatment and rate of (re-) growth and the final outcome in each case. Results We identified six patients with good initial response but delayed VS regrowth at a faster rate than pre-SRS. The mean growth rate for these VS was 0.347 mm/month (range 0.04–0.78 mm/month) prior to treatment; the mean growth rate at the time of delayed re-growth was 0.48 mm/month (range 0.17–0.75 mm/month); this did not reach the level of statistical significance (p = 0.08). This regrowth occurred at a mean time of 42 months (range 36–66 months) post-SRS and stopped 22 months (mean, range 12–36 months) post regrowth detection in all cases. Conclusions Given that delayed post-SRS VS regrowth can occur in approximately 4% of the treated cases, it is important to continue close clinical and radiological follow-up. Despite this abnormal behaviour, VS do stop growing again; still, patients should be made aware of the possibility of this uncommon VS behaviour following SRS.

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Section: Clinical Implications and Long-term Imagingmentioning

confidence: 60%

Section: Main Findingsmentioning

confidence: 96%

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Long-term growth patterns of vestibular schwannomas after stereotactic radiotherapy: delayed re-growth

Conlan

Kontorinis

2022

Eur Arch Otorhinolaryngol

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“…Since increased usage of magnetic resonance imaging led to earlier diagnosis, more patients are now asymptomatic, and watchful observation is often the choice. When it comes to SRS, the tumor control rate is comparable to conventional microsurgery 21 . It was able to maintain serviceable hearing at four years in 72.2% of the total patient in a study 22 .…”

Section: Discussionmentioning

confidence: 98%

Machine learning approach for prediction of hearing preservation in vestibular schwannoma surgery

Cha

Shin

Kim

et al. 2020

Sci Rep

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in vestibular schwannoma patients with functional hearing status, surgical resection while preserving the hearing is feasible. Hearing levels, tumor size, and location of the tumor have been known to be candidates of predictors. We used a machine learning approach to predict hearing outcomes in vestibular schwannoma patients who underwent hearing preservation surgery: middle cranial fossa, or retrosigmoid approach. After reviewing the medical records of 52 patients with a pathologically confirmed vestibular schwannoma, we included 50 patient's records in the study. Hearing preservation was regarded as positive if the postoperative hearing was within serviceable hearing (50/50 rule). The categorical variable included the surgical approach, and the continuous variable covered audiometric and vestibular function tests, and the largest diameter of the tumor. Four different algorithms were lined up for comparison of accuracy: support vector machine(SVM), gradient boosting machine(GBM), deep neural network(DNN), and diffuse random forest(DRF). The average accuracy of predicting hearing preservation ranged from 62% (SVM) to 90% (DNN). The current study is the first to incorporate machine learning methodology into a prediction of successful hearing preservation surgery. Although a larger population may be needed for better generalization, this study could aid the surgeon's decision to perform a hearing preservation approach for vestibular schwannoma surgery.Vestibular schwannomas (VSs), or acoustic neuromas are benign tumors arising from the cochleovestibular nerve, which grows slowly 1 . It accounts for 6-8% of all intracranial tumors and is the most common cerebellopontine angle tumor 2 . Recently, with the help of better access to magnetic resonance imaging, the incidence has been increased, and the tumor size at the time of diagnosis has decreased 3,4 . With more early detection rates, more patients are asymptomatic when diagnosed. In these patients, the following management options may all be feasible: watchful waiting, surgery, or stereotactic radiosurgery(SRS). However, there are no clear guidelines or consensus on the optimal management of small VSs, and the optimal treatment is still under debate 5,6 . Treatment options differ individually and are dependent upon the physician's experience, the size and growth rate of the tumor, age, patient's preference, and hearing status. If the tumor is too big, or hearing is below serviceable hearing, hearing preservation is not essential in treatment 7 . Nevertheless, in small to medium-sized tumors with serviceable hearing, hearing preservation surgeries can be offered. Currently, middle cranial fossa approach(MCFA) and retrosigmoid approach(RSA) are the two most commonly used approaches to remove VSs.The selection between the two approaches depends on the size and location of the tumor, and the surgeon's preference, as each procedure has its strengths in exposing regions of the internal auditory canal or cerebellopontine angle. The preservation rate of MCFA and RSA varies...

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“…For gamma knife, a control rate of 98% after a median follow-up period of 5.8 years was reported ( 25 ). For the “watch-and-wait” strategy, a meta-analysis demonstrated in median 43% of schwannoma progressions in a similar follow-up period of 3.2 years ( 26 ).…”

Section: Discussionmentioning

confidence: 99%

Effectiveness and Toxicity of Fractionated Proton Beam Radiotherapy for Cranial Nerve Schwannoma Unsuitable for Stereotactic Radiosurgery

et al. 2021

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PurposeIn this benign tumor entity, preservation of cranial nerve function is of special importance. Due to its advantageous physical properties, proton beam radiotherapy (PRT) is a promising approach that spares healthy tissue. Could PRT go along with satisfactory preservation rates for cranial nerve function without compromising tumor control in patients with cranial nerve schwannoma unsuitable for stereotactic radiosurgery?MethodsWe analyzed 45 patients with cranial nerve schwannomas who underwent PRT between 2012 and 2020 at our institution. Response assessment was performed by MRI according to RECIST 1.1, and toxicity was graded following CTCAE 5.0.ResultsThe most common schwannoma origin was the vestibulocochlear nerve with 82.2%, followed by the trigeminal nerve with 8.9% and the glossopharyngeal nerve as well as the vagal nerve, both with each 4.4%. At radiotherapy start, 58% of cranial nerve schwannomas were progressive and 95.6% were symptomatic. Patients were treated with a median total dose of 54 Gy RBE in 1.8 Gy RBE per fraction. MRI during the median follow-up period of 42 months (IQR 26–61) revealed stable disease in 93.3% of the patients and partial regression in 6.7%. There was no case of progressive disease. New or worsening cranial nerve dysfunction was found in 20.0% of all patients, but always graded as CTCAE °I-II. In seven cases (16%), radiation-induced contrast enhancements (RICE) were detected after a median time of 14 months (range 2–26 months). RICE were asymptomatic (71%) or transient symptomatic (CTCAE °II; 29%). No CTCAE °III/IV toxicities were observed. Lesions regressed during the follow-up period in three of the seven cases, and no lesion progressed during the follow-up period.ConclusionThese data demonstrate excellent effectiveness with 100% local control in a median follow-up period of 3.6 years with a promising cranial nerve functional protection rate of 80%. RICE occurred in 16% of the patients after PRT and were not or only mildly symptomatic.

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Long-Term Tumor Control Rates Following Gamma Knife Radiosurgery for Acoustic Neuroma

Cited by 17 publications

References 25 publications

Long-term growth patterns of vestibular schwannomas after stereotactic radiotherapy: delayed re-growth

Long-term growth patterns of vestibular schwannomas after stereotactic radiotherapy: delayed re-growth

Machine learning approach for prediction of hearing preservation in vestibular schwannoma surgery

Effectiveness and Toxicity of Fractionated Proton Beam Radiotherapy for Cranial Nerve Schwannoma Unsuitable for Stereotactic Radiosurgery

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