Challenging the concept that late recurrence and death from tumor are common after fractionated radiotherapy for benign meningioma

2019 ◽  
Vol 137 ◽  
pp. 55-60 ◽  
Author(s):  
Lillie O'steen ◽  
Robert J. Amdur ◽  
Christopher G. Morris ◽  
William M. Mendenhall
Keyword(s):  
Late Recurrence ◽  
Benign Meningioma ◽  
Fractionated Radiotherapy

Stroke rate after external fractionated radiotherapy for benign meningioma

2021 ◽  
Author(s):  
Dimitri Vanmarcke ◽  
Johan Menten ◽  
Gilles Defraene ◽  
Frank Van Calenbergh ◽  
Steven De Vleeschouwer ◽  
...  
Keyword(s):  
Stroke Rate ◽  
Benign Meningioma ◽  
Fractionated Radiotherapy

Dose fractionation in stereotactic radiotherapy for parasellar meningiomas: radiobiological considerations of efficacy and optic nerve tolerance

2004 ◽  
pp. 390-395 ◽  
Author(s):  
Dennis C. Shrieve ◽  
Lisa Hazard ◽  
Kenneth Boucher ◽  
Randy L. Jensen
Keyword(s):  
Single Dose ◽  
Optic Nerve ◽  
Optic Neuropathy ◽  
Dose Fractionation ◽  
Benign Meningioma ◽  
Content Type ◽  
Fractionated Radiotherapy ◽  
Statistical Estimates ◽  
Fine Print

Object. Benign meningiomas have been shown to be equally well controlled with single-dose radiosurgery (15 Gy) and fractionated doses of 54 Gy in 30 fractions after adequate follow up. For a subset of patients with meningioma, the optic apparatus is dose limiting when considering single-dose stereotactic radiosurgery, with tolerance estimated to be 8 to 10 Gy. Recently, hypofractionated regimens have been used to treat benign meningiomas with a small number of fractions. An analysis of the expected efficacy of hypofractionation compared with the estimated optic tolerance to fractionated radiotherapy was undertaken. Methods. Using the assumption that 15 Gy in one fraction and 54 Gy in 30 fractions are isoeffective for control of benign meningioma, an α/β for meningioma is calculated to be 3.28 Gy. Invoking a 10% error for these doses (15 Gy ± 10% is equivalent to 54 Gy ± 10%) results in upper and lower limits of the estimate for α/β of 3.85 Gy and 2.7 Gy. Using these estimates, isoeffect curves for control of meningioma were constructed for fraction numbers of one to 45. Best estimates of optic nerve/chiasm tolerance to single doses of radiation are 8 to 10 Gy, with the reported incidence of optic neuropathy increasing significantly at higher doses. This is consistent with the optic ret model, which also predicts for optic tolerance following fractionated radiotherapy. Comparison of optic tolerance and estimates of efficacious doses at fraction numbers between one and 30 were made. Statistical estimates of patient numbers and duration of follow up required to rule out optic neuropathy following radiotherapy were made. Single doses of radiation required to treat benign meningioma optimally (13.5–16.5 Gy) clearly exceed the estimated and reported clinical tolerance of the optic nerves and chiasm. The application of equivalent biological doses in a small number of fractions continues to exceed optic tolerance until at least 25 fractions are applied. Conclusions. The use of small numbers of fractions to treat patients with meningioma when portions of optic nerve or chiasm receive full dose may result in undertreatment of the tumor and/or exceeding optic nerve tolerance. In such cases standard fractionation is recommended. Ruling out a low, yet unacceptable, risk of optic neuropathy may require the close study of many patients with long-term follow-up evaluation.

Dose fractionation in stereotactic radiotherapy for parasellar meningiomas: radiobiological considerations of efficacy and optic nerve tolerance

2004 ◽  
Vol 101 (Supplement3) ◽  
pp. 390-395 ◽  
Author(s):  
Dennis C. Shrieve ◽  
Lisa Hazard ◽  
Kenneth Boucher ◽  
Randy L. Jensen
Keyword(s):  
Single Dose ◽  
Optic Nerve ◽  
Optic Neuropathy ◽  
Dose Fractionation ◽  
Benign Meningioma ◽  
Content Type ◽  
Fractionated Radiotherapy ◽  
Statistical Estimates ◽  
Fine Print

Object. Benign meningiomas have been shown to be equally well controlled with single-dose radiosurgery (15 Gy) and fractionated doses of 54 Gy in 30 fractions after adequate follow up. For a subset of patients with meningioma, the optic apparatus is dose limiting when considering single-dose stereotactic radiosurgery, with tolerance estimated to be 8 to 10 Gy. Recently, hypofractionated regimens have been used to treat benign meningiomas with a small number of fractions. An analysis of the expected efficacy of hypofractionation compared with the estimated optic tolerance to fractionated radiotherapy was undertaken. Methods. Using the assumption that 15 Gy in one fraction and 54 Gy in 30 fractions are isoeffective for control of benign meningioma, an α/β for meningioma is calculated to be 3.28 Gy. Invoking a 10% error for these doses (15 Gy ± 10% is equivalent to 54 Gy ± 10%) results in upper and lower limits of the estimate for α/β of 3.85 Gy and 2.7 Gy. Using these estimates, isoeffect curves for control of meningioma were constructed for fraction numbers of one to 45. Best estimates of optic nerve/chiasm tolerance to single doses of radiation are 8 to 10 Gy, with the reported incidence of optic neuropathy increasing significantly at higher doses. This is consistent with the optic ret model, which also predicts for optic tolerance following fractionated radiotherapy. Comparison of optic tolerance and estimates of efficacious doses at fraction numbers between one and 30 were made. Statistical estimates of patient numbers and duration of follow up required to rule out optic neuropathy following radiotherapy were made. Single doses of radiation required to treat benign meningioma optimally (13.5–16.5 Gy) clearly exceed the estimated and reported clinical tolerance of the optic nerves and chiasm. The application of equivalent biological doses in a small number of fractions continues to exceed optic tolerance until at least 25 fractions are applied. Conclusions. The use of small numbers of fractions to treat patients with meningioma when portions of optic nerve or chiasm receive full dose may result in undertreatment of the tumor and/or exceeding optic nerve tolerance. In such cases standard fractionation is recommended. Ruling out a low, yet unacceptable, risk of optic neuropathy may require the close study of many patients with long-term follow-up evaluation.

Late recurrence of anal fissure after conservative therapy with botulinum toxin

2001 ◽  
Vol 120 (5) ◽  
pp. A398-A398
Author(s):  
M MINGUEZ ◽  
A ESPI ◽  
V SANCHIZ ◽  
I PASCUAL ◽  
E GARCIAGRANERO ◽  
...  
Keyword(s):  
Botulinum Toxin ◽  
Anal Fissure ◽  
Conservative Therapy ◽  
Late Recurrence

Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 90-92 ◽  
Author(s):  
Mark E. Linskey
Keyword(s):  
Gamma Knife ◽  
Stereotactic Radiotherapy ◽  
Three Dimensional ◽  
Late Recurrence ◽  
Vestibular Schwannomas ◽  
Tumor Control ◽  
Complication Rates ◽  
Content Type ◽  
Single Fraction ◽  
Fine Print

✓ By definition, the term “radiosurgery” refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed “stereotactic radiotherapy.” There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image—targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS “halo effect.” It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the expense of potential late recurrence. The answer to minimizing complications while maintaining maximum tumor control is improved conformality of radiosurgery dose planning and not resorting to homeopathic radiosurgery doses or hypofractionation radiotherapy schemes.

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