Assessment of the α/ß ratios for arteriovenous malformations, meningiomas, acoustic neuromas, and the optic chiasma

Vernimmen, Frederik; Slabbert, Jacobus

doi:10.3109/09553001003667982

Cited by 61 publications

(36 citation statements)

References 70 publications

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“…19 The single-fraction high-dose technique, according to radiobiological experience, is the best option for treating slow-growing lesions that respond late to radiation therapy. 25,42 These lesions should respond to a single, high-dose radiation better than to a conventionally fractionated dosage (50-55 Gy in 25-30 fractions). Like bone and nervous tissue, arteriovenous malformations, meningiomas, and neuromas are late responders, and their a/b ratio is generally considered low, where coefficient a represents a lethal single-impact injury and coefficient b a lethal injury due to accumulation of sublethal doses.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, the current standard therapeutic dose (12-13 Gy) may be too high and not well tolerated by healthy surrounding nervous structures, with potential adverse radiation effects, without effecting rapid volume reduction. 3,42 Multisession stereotactic radiosurgery (SRS) 1,5,6,13,17 performed using the CyberKnife (Accuray Inc.) in 2-5 fractions has been the main therapeutic choice at our institution since January 2003 for patients harboring VSs. The present study will contribute to the debate on the therapeutic strategies for VSs, by showing disease outcomes following multisession SRS in a series of patients with lesions larger than 8 cm ).…”

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confidence: 99%

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Multisession stereotactic radiosurgery for large vestibular schwannomas

Casentini

Fornezza

Perini

et al. 2015

JNS

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OBJECT Microsurgery is not the only option for larger vestibular schwannomas (VSs); recent reviews have confirmed the feasibility and efficacy of radiosurgery for larger VSs. This study illustrates the outcomes of a series of large VSs after multisession stereotactic radiosurgery (SRS). METHODS A series of 33 VSs larger than 8 cm3 (range 8–24 cm3, mean 11 cm3, median 9.4 cm3) were treated using the CyberKnife from 2003 to 2011 with the multisession SRS technique in 2–5 fractions (14–19.5 Gy). Five patients had undergone surgical removal and 5 had ventriculoperitoneal shunts. Nine patients were eligible for but refused surgery. Twelve patients were older than 70 years and 5 were younger than 40 years. Two female patients had neurofibromatosis. RESULTS The follow-up period ranged from 12 to 111 months (median 48 months); radiological growth control was achieved in 94% of cases: 19 tumors (58%) displayed no size variation or reduction in tumor diameter; 12 (36%), after a transient enlargement, presented with arrested growth or shrinkage. Seven patients had a volume reduction of more than 50%. Two patients (6%) needed debulking and 2 were treated with ventriculoperitoneal shunts. Actuarial progressionfree survival rates at 1 year and 5 years were 97% and 83%, respectively. Hearing was retained in 7 of the 8 patients with serviceable baseline hearing. Adverse events were limited to 1 case each of vertigo, tongue paresthesia, and trigeminal neuralgia. CONCLUSIONS The good control rate obtained with multisession SRS deepens the controversy of the radiobiology of VSs and may extend the indication of radiation therapy (fractionated or SRS) for large VSs to include patients without symptoms of mass effect. The limited number of cases and short follow-up period do not provide sufficient support for widespread application of multisession SRS in young patients. Further studies with multisession SRS are warranted.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Multisession stereotactic radiosurgery for large vestibular schwannomas

Casentini

Fornezza

Perini

et al. 2015

JNS

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“…31 The BED of a typical 3D conformal RT protocol for human meningioma (27 fractions of 2 Gy for a total dose of 54 Gy given in 6 weeks) was a Gy 3 value of 90 Gy. 32 The BED of our regimen (33 Gy given in 5 days) was 105.6 Gy (17% higher).…”

Section: Follow-up:-mentioning

confidence: 76%

“…26,32,33 The Monte Carlo statistic calculation algorithm allowed a better dose calculation at different tissue interfaces, where higher punctual doses (D max ) could be generated. Moreover, doses to the OARs were lower than the constraints, showing the possibility of further dose escalation to the PTV.…”

Section: Follow-up:-mentioning

confidence: 99%

Stereotactic Volume Modulated Arc Radiotherapy Protocol for Canine Intracranial Meningioma.

Dolera¹,

Malfassi²,

Carrara³

et al. 2017

IJAR

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Objective: to assess High Dose Hypofractionated Volume Modulated Arc Radiotherapy (HDH-VMAT) feasibility and clinical efficacy in canine meningiomas. Design: a prospective study was conducted on thirty-three patients with a presumptive diagnosis of encephalic meningiomas assumed from Magnetic Resonance Imaging (MRI) findings. Methods: all dogs, whose neurological status was scored through the use of an innovative evaluation scale (Romanengo Veterinary Neurological Scale -RVNS), received HDH-VMAT by a Linear Accelerator (LINAC) equipped with an external beam modulator micro-multileaf collimator and an XVI Cone Beam Computed Tomography system (CBCT). The prescribed mean dose was 33 Gy delivered in 5 fractions. The treatment feasibility was tested through planned and delivered dose agreement checks. Regular clinical examinations were performed during and after irradiation time with regard to mentation, deambulation, cranial nerve dysfunction and seizures. Serial MRI exams were done 60 days after irradiation and after 4, 6, 12, 18, 24 months. Volumetric disease reduction criteria implemented with clinical neurological systematic evaluation were adopted to assess the course and to categorize patients' response. Results: complete and partial responses were observed on the whole in 65,5% of alive patients 24 months after irradiation. Two-year overall and disease-specific survival rates were 74.3% and 97.4%, respectively, and the putative radiotoxic effects were found to be few and slight. Conclusions: HDH-VMAT is a valid therapeutic option for encephalic canine meningioma. Volumetric MRI evaluation together with the hereby proposed RVNS should be considered for the evaluation of the post-treatment response.Copy Right, IJAR, 2017,. All rights reserved.

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“…Normal tissue has an / in the range of 2-3 Gy (19). This small difference between the /ß values of normal surrounding tissue versus the target tissue theoretically allows for an increase in the differential radiation effect on both these tissues by increasing the number of fractions, this is called therapeutic gain (21,22,23,27). Most of this gain is achieved by going from 1 fraction to about 7-9 fractions and than flattens off going to 25-30 fractions.…”

Section: Radiobiologymentioning

confidence: 99%

Radiation Therapy in the Management of Meningiomas

Vernimmen¹

2012

Meningiomas - Management and Surgery

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Assessment of the α/ß ratios for arteriovenous malformations, meningiomas, acoustic neuromas, and the optic chiasma

Cited by 61 publications

References 70 publications

Multisession stereotactic radiosurgery for large vestibular schwannomas

Multisession stereotactic radiosurgery for large vestibular schwannomas

Stereotactic Volume Modulated Arc Radiotherapy Protocol for Canine Intracranial Meningioma.

Radiation Therapy in the Management of Meningiomas

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