Radiation-Induced Sarcoma in a Large Vestibular Schwannoma Following Stereotactic Radiosurgery: Case Report

Schmitt, William R.; Carlson, Matthew L.; Giannini, Caterina; Driscoll, Colin L. W.; Link, Michael J.

doi:10.1227/neu.0b013e31820780b1

Cited by 46 publications

(27 citation statements)

References 37 publications

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“…7,17,25 Finally, a small risk (< 1%) of malignant transformation or radiation-induced neoplasms is present following radiosurgery. 41,58,59 Despite data suggesting the use of radiotherapy for the treatment of VSs < 3 cm, our data show that this is not the most common modality of treatment (Fig. 1).…”

Section: Discussioncontrasting

confidence: 75%

Vestibular schwannomas in the modern era: epidemiology, treatment trends, and disparities in management

Babu

Sharma

Bagley

et al. 2013

JNS

149

158

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Object There are a variety of treatment options for the management of vestibular schwannomas (VSs), including microsurgical resection, radiotherapy, and observation. Although the choice of treatment is dependent on various patient factors, physician bias has been shown to significantly affect treatment choice for VS. In this study the authors describe the current epidemiology of VS and treatment trends in the US in the modern era. They also illustrate patient and tumor characteristics and elucidate their effect on tumor management. Methods Patients diagnosed with VS were identified through the Surveillance, Epidemiology, and End Results database, spanning the years 2004–2009. Age-adjusted incidence rates were calculated and adjusted using the 2000 US standard population. The chi-square and Student t-tests were used to evaluate differences between patient and tumor characteristics. Multivariate logistic regression was performed to determine the effects of various patient and tumor characteristics on the choice of tumor treatment. Results A total of 6225 patients with VSs treated between 2004 and 2009 were identified. The overall incidence rate was 1.2 per 100,000 population per year. The median age of patients with VS was 55 years, with the majority of patients being Caucasian (83.16%). Of all patients, 3053 (49.04%) received surgery only, with 1466 (23.55%) receiving radiotherapy alone. Both surgery and radiation were only used in 123 patients (1.98%), with 1504 patients not undergoing any treatment (24.16%). Increasing age correlated with decreased use of surgery (OR 0.95, 95% CI 0.95–0.96; p < 0.0001), whereas increasing tumor size was associated with the increased use of surgery (OR 1.04, 95% CI 1.04–1.05; p < 0.0001). Older age was associated with an increased likelihood of conservative management (OR 1.04, 95% CI 1.04–1.05; p < 0.0001). Racial disparities were also seen, with African American patients being significantly less likely to receive surgical treatment compared with Caucasians (OR 0.50, 95% CI 0.35–0.70; p < 0.0001), despite having larger tumors at diagnosis. Conclusions The incidence of vestibular schwannomas in the US is 1.2 per 100,000 population per year. Although many studies have demonstrated improved outcomes with the use of radiotherapy for small- to medium-sized VSs, surgery is still the most commonly used treatment modality for these tumors. Racial disparities also exist in the treatment of VSs, with African American patients being half as likely to receive surgery and nearly twice as likely to have their VSs managed conservatively despite presenting with larger tumors. Further studies are needed to elucidate the reasons for treatment disparities and investigate the nationwide trend of resection for the treatment of small VSs.

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Section: Discussioncontrasting

confidence: 75%

Vestibular schwannomas in the modern era: epidemiology, treatment trends, and disparities in management

Babu

Sharma

Bagley

et al. 2013

JNS

149

158

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“…6,15,20 However, there is a concern that irradiation itself might play a causative role in secondary malignancy, which is a rare but a serious complication after radiation treatment, as reported in several case reports. 1,7,20,30,34 In a large study of 440 patients treated with Gamma Knife surgery for VS and with a median follow-up period of 12.5 years, the authors reported only one case of developing malignant change. The overall malignant transformation rate was calculated to 0.3%, with an annual incidence of 0.02%.…”

Section: Discussionmentioning

confidence: 99%

“…Several case reports lack a histological diagnosis of the primary tumor prior to irradiation. 15,30 It might be due to the fact that the primary diagnosis is often presumptive, based on the imaging characteristics of the tumor only, and SRS or SRT is performed as a primary treatment without any histological investigation. This can increase the risk of an erroneous diagnosis of the irradiation-induced malignant transformation of the tumor.…”

Section: Discussionmentioning

confidence: 99%

“…13,28 The short latency period in these cases could indicate that a malignant component already existed prior to irradiation, and might be aggravated by it, as radiation-induced malignancy usually develops over a longer period of time. 1,7,22,30 However, there is no consensus on the minimum latency period between radiation exposure and tumor development, and further work is necessary to establish a reference latency interval for radiation-induced tumors. Finally, in some case reports, patients with malignant VS have underlying NF2, a genetic condition known to be associated with a higher risk of malignant tumors, especially after radiation treatment, 2,32 and which contests Cahan's Criterion 4.…”

Section: Discussionmentioning

confidence: 99%

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Late malignant transformation of vestibular schwannoma in the absence of irradiation: case report

Bashir¹,

Poulsgaard²,

Broholm

et al. 2016

JNS

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abbreviatioNs MPNST = malignant peripheral nerve sheath tumor; NF2 = neurofibromatosis Type 2; SRS = stereotactic radiosurgery; SRT = stereotactic radiotherapy; VS = vestibular schwannoma. Late malignant transformation of vestibular schwannoma (VS) following irradiation has previously been reported 29 times in the literature. Here, the authors report the first late malignant transformation of VS unrelated to neurofibromatosis or radiation exposure. After undergoing a near-total excision of a histologically benign VS, the patient developed malignant regrowth of the tumor remnant 42 months after the primary excision. This case challenges the dogmatic belief of absolute causality between radiation exposure and late malignant transformation of VS, and has important implications regarding future counseling and consent for the treatment of patients with VS.

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“…The incidence is unknown and may be related to endothelial injury and changes in blood-brain barrier and acceleration of atherosclerosis [63]. While rates of radiation-induced malignant transformation are very rare, there are at least 33 cases of malignant tumors following STR for VS [42,45,52,[64][65][66][67][68][69] with nearly half of these cases occurring in NF2 patients [45,67,69]. The most commonly reported form of malignancy has been peripheral nerve sheath tumors; however, sarcomas, malignant meningiomas, and glioblastomas have been reported.…”

Section: Complicationsmentioning

confidence: 99%

Vestibular Schwannomas: Surgical and Nonsurgical Management

2015

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Management options of vestibular schwannomas continue to evolve as surgical, radiation, and radiologic imaging techniques and technology change and improve over time. Currently, three options for these tumors exist and include primary surgical extirpation, stereotactic radiation, and observation with serial imaging. Skull base surgeons are charged with providing the patient with a comprehensive discussion of each option based on the inherit risks and benefits of each option to craft a management plan based on numerous factors that include age, tumor location, and size, hearing level at presentation and any medical comorbidities that may influence functional outcomes and quality of life. The purpose of this article was to review the surgical and non-surgical approaches to tumor management highlighting the risks and benefits and ongoing controversies between modalities regarding optimal functional outcomes. A particular emphasis is placed on hearing preservation and facial nerve function after treatment.

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Radiation-Induced Sarcoma in a Large Vestibular Schwannoma Following Stereotactic Radiosurgery: Case Report

Cited by 46 publications

References 37 publications

Vestibular schwannomas in the modern era: epidemiology, treatment trends, and disparities in management

Vestibular schwannomas in the modern era: epidemiology, treatment trends, and disparities in management

Late malignant transformation of vestibular schwannoma in the absence of irradiation: case report

Vestibular Schwannomas: Surgical and Nonsurgical Management

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