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.

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.

Surgical management of meningiomas involving the optic nerve sheath

2004 ◽  
Vol 101 (6) ◽  
pp. 951-959 ◽  
Author(s):  
Uta Schick ◽  
Uwe Dott ◽  
Werner Hassler
Keyword(s):  
Optic Nerve ◽  
Postoperative Radiotherapy ◽  
Visual Outcome ◽  
Tumor Location ◽  
Optic Nerve Sheath ◽  
Optic Canal ◽  
Content Type ◽  
Nerve Sheath ◽  
Fine Print

Object. The management of optic nerve sheath meningiomas (ONSMs) remains controversial but includes surgery, radiotherapy, and plain observation. Surgery is often thought to result in postoperative blindness. The authors report on a large series of patients surgically treated for ONSM, with an emphasis on the visual outcome. Methods. Seventy-three patients with ONSMs who had undergone surgery between 1991 and 2002 were retrospectively analyzed. The standard surgical approach consisted of pterional craniotomy, intradural (54 patients) or extradural (10 patients) unroofing of the optic canal, or a combined procedure (seven patients). Thirty-two tumors demonstrated extension through the optic canal. Twenty-nine tumors reached the chiasm or contralateral side. Patients with intraorbital flat tumors should undergo radiotherapy instead of surgery. Those with a large intraorbital mass and no useful vision should undergo surgery. Tumors extending intracranially through the optic canal are amenable to decompression of the optic canal and resection of the intracranial portion. The follow-up period was a mean 45.4 months (range 6–144 months). Ten patients underwent postoperative radiotherapy. Visual acuity was not significantly influenced by surgery but did become worse with a longer duration of preoperative symptoms and a longer follow-up period. A tumor location in the optic canal was another negative factor. Radiotherapy preserved vision in five of 10 cases. Conclusions. The loss of vision in patients with ONSM is only a matter of time. In patients with good vision the role of radiotherapy becomes more important. Surgery is recommended for intracranial tumors to prevent contralateral extension.

Temporary ventricular drainage and emergency radiotherapy in the management of hydrocephalus associated with germinoma

2002 ◽  
Vol 96 (6) ◽  
pp. 1020-1022 ◽  
Author(s):  
John M. Buatti ◽  
William A. Friedman
Keyword(s):  
Obstructive Hydrocephalus ◽  
External Ventricular Drainage ◽  
Tumor Control ◽  
Ventricular Drainage ◽  
Content Type ◽  
Fractionated Radiotherapy ◽  
Novel Strategy ◽  
Emergency Radiotherapy ◽  
Fine Print

Object. The authors used an alternative strategy to avoid shunt placement for hydrocephalus associated with germinoma, and the ensuing complications. Methods. Between 1998 and 2000, five patients presenting with germinomas of the pineal area and symptomatic obstructive hydrocephalus were treated with a novel strategy. On arrival, they underwent ventriculostomy placement and one of several surgical procedures to obtain tissue for diagnosis. Within several days of the initial diagnosis, stereotactically guided fractionated radiotherapy was started. All patients experienced rapid tumor shrinkage and resolution of hydrocephalus, allowing discontinuation of external ventricular drainage without the need for permanent shunting of cerebrospinal fluid. To date, follow up reveals 100% radiographically and clinically confirmed tumor control. Conclusions. Prompt resolution of hydrocephalus and absence of complications make this a potentially valuable therapy for control of germinomas and their symptoms.

Post-decompression optic neuropathy

1985 ◽  
Vol 63 (2) ◽  
pp. 196-199 ◽  
Author(s):  
Roy W. Beck ◽  
Harry S. Greenberg
Keyword(s):  
Optic Nerve ◽  
Visual Field ◽  
Optic Neuropathy ◽  
Fiber Bundle ◽  
Visual Field Loss ◽  
Intracranial Tumors ◽  
Visual Recovery ◽  
Content Type ◽  
Decompressive Craniotomy ◽  
Fine Print

✓ Blindness resulting from a decompressive craniotomy is uncommon. Five patients with intracranial tumors and papilledema who developed a bilateral optic neuropathy during an apparently uncomplicated craniotomy are presented. Symptoms of visual field loss were minimal preoperatively in four. Visual recovery in general was poor. The nerve fiber bundle pattern of visual field loss in these cases implicates the optic disc as the site of damage in this disorder. It is postulated that hypoperfusion to the prelaminar portion of the optic nerve is the underlying cause.

Long-term follow up of progesterone receptor status in benign meningioma: a prognostic indicator of recurrence?

2000 ◽  
Vol 92 (3) ◽  
pp. 401-405 ◽  
Author(s):  
Paul E. Fewings ◽  
Robert D. E. Battersby ◽  
Walter R. Timperley
Keyword(s):  
Progesterone Receptor ◽  
Benign Tumors ◽  
Progesterone Receptor Status ◽  
Benign Meningioma ◽  
Content Type ◽  
Receptor Status ◽  
Chi Square Analysis ◽  
Fine Print

Object. A long-term prospective analysis of patients with benign meningioma was undertaken to determine whether progesterone receptor (PR) status of the excised tumor has any influence on recurrence.Methods. Between 1983 and 1985, a total of 62 meningiomas in 53 patients (age range 19–79 years, mean age 55.6 years) were studied for clinical, histological, and pathological characteristics, including hormone receptor status and DNA features. Progesterone receptor status was quantified by cryostat section assay, and then factors affecting recurrence were analyzed. During 1997 all case records were reviewed to determine whether tumor had recurred in any patient, and PR status was correlated with tumor recurrence.Of the 62 tumors, 60 were benign, and of the benign tumors 29 (48%) were PR positive. Patients harboring 14 of the 60 benign tumors were lost to follow up. Of the 46 tumors included in the final analysis, 13 were recurrent (all within 5 years) and 33 were nonrecurrent. Of the 33 nonrecurrent tumors, 14 had not recurred 5 to 10 years postresection and 19 had not recurred after more than 10 years. Chi-square analysis of the results did not show an association between recurrence and patient's sex, extent of resection, histological subtype, or tumor site but did show an association between recurrence and PR negativity (p = 0.013).Conclusions. The results indicate that benign meningiomas that are PR positive are less likely to recur, a finding that has prognostic and therapeutic implications.

Efficacy of gamma knife radiosurgery for nonfunctioning pituitary adenomas: a quantitative follow up with magnetic resonance imaging—based volumetric analysis

2002 ◽  
Vol 97 ◽  
pp. 429-432 ◽  
Author(s):  
Berndt Wowra ◽  
Walter Stummer
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pituitary Adenomas ◽  
Gamma Knife Radiosurgery ◽  
Volumetric Analysis ◽  
Resonance Imaging ◽  
Content Type ◽  
Fractionated Radiotherapy ◽  
Fine Print

Object. The authors assessed the efficacy of gamma knife radiosurgery (GKS) for nonfunctioning pituitary adenomas (NPAs) by sequential quantitative determinations of tumor volume and neurological and endocrinological follow-up examinations. Methods. Through May of 2000, 45 patients with NPA were treated by GKS. Complete neurological and endocrinological follow-up information was obtained. In 30 patients (67%), follow-up examinations included stereotactic magnetic resonance imaging involving the GammaPlan software for sequential measurements of the NPA volume. These patients constitute the basis of this study. Sequential volume measurements after GKS were compared with initial tumor volumes at the date of GKS to quantify the therapeutic result. All data were stored prospectively in a computerized database. The median dose to the tumor margin was 16 Gy (range 11–20 Gy). The mean prescription isodose was 55% (range 45–75%). All except one patient (97%) underwent surgery for NPA before GKS. Fractionated radiotherapy was not administered. Median follow up after GKS was 55 months (range 28–86 months). The actuarial long-term recurrence-free survival was 93% with respect to a single GKS and 100% if a repeated GKS was included. Neurological side effects were not detected. The actuarial risk of radiosurgery-induced pituitary damage was calculated to be 14% after 6 years. The volumetric analysis revealed a temporary swelling of the NPA in four patients, followed by shrinkage of the lesion. This is the first time this has been observed in pituitary adenomas. Conclusions. Postoperative GKS for residual or recurrent small fragments of NPAs is effective and safe. With regard to the issues of radioprotection and therapeutic morbidity, it seems superior to fractionated radiotherapy. Quantification of tumor reduction is a valuable tool for documenting a therapeutic response and for identifying tumor recurrence. As part of a radiosurgical standard protocol, the follow-up examination for NPAs should include tumor volumetric analysis.

Gamma knife surgery for treatment of residual nonfunctioning pituitary adenomas after surgical debulking

2004 ◽  
Vol 100 (3) ◽  
pp. 438-444 ◽  
Author(s):  
Marco Losa ◽  
Micol Valle ◽  
Pietro Mortini ◽  
Alberto Franzin ◽  
Camillo Ferrari da Passano ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Lower Risk ◽  
Tumor Volume ◽  
Sella Turcica ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Fractionated Radiotherapy ◽  
Surgical Debulking ◽  
Fine Print

Object. Radiation therapy diminishes the risk of recurrence of incompletely removed nonfunctioning pituitary adenoma (NPA). The authors evaluated the efficacy and safety of gamma knife surgery (GKS) in patients with residual NPA following surgical debulking of the tumor. Methods. Fifty-four patients, 26 men and 28 women, ranging in age from 29 to 72 years underwent gamma knife treatment. Baseline and follow-up studies involved magnetic resonance imaging, hormone evaluation, and neuroophthalmological examination 6 and 12 months after GKS and at yearly intervals thereafter. The mean follow up after GKS was 41.1 ± 3.1 months. Two of 52 patients undergoing follow up had a recurrence 40 and 49 months after GKS. In both of these patients the treated lesion had reduced in size, but a new lesion appeared in the contralateral side of the sella turcica. The recurrence-free interval at 5 years was 88.2% (95% confidence interval 72.6–100%). Tumor volume decreased from a baseline value of 2.3 ± 0.2 to 1.7 ± 0.2 cm3 at the last follow up (p < 0.001). Twenty-two patients (42.3%) had a 20% or greater reduction in tumor volume. The administered radiation dose had been significantly higher in patients who experienced tumor reduction. Visual function and motility did not deteriorate in any patient. New cases of hypogonadism, hypothyroidism, and hypoadrenalism occurred in 12.5, 8.6, and 2.3%, respectively, of assessable patients at risk. Conclusions. Gamma knife surgery was effective in controlling the growth of residual NPA after previously performed maximal surgical debulking. The major advantage of GKS compared with fractionated radiotherapy seems to be a lower risk of side effects, especially a lower risk of hypopituitarism.

Evaluation of gamma thalamotomy for parkinsonian and other tremors: survival of neurons adjacent to the thalamic lesion after gamma thalamotomy

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 120-127 ◽  
Author(s):  
Chihiro Ohye ◽  
Tohru Shibazaki ◽  
Junji Ishihara ◽  
Jie Zhang
Keyword(s):  
Tissue Reaction ◽  
Vascular Lesions ◽  
Thalamic Lesion ◽  
Mr Images ◽  
Unsatisfactory Result ◽  
Content Type ◽  
Rhythmic Discharge ◽  
Latent Interval ◽  
Fine Print

Object. The effects of gamma thalamotomy for parkinsonian and other kinds of tremor were evaluated. Methods. Thirty-six thalamotomies were performed in 31 patients by using a 4-mm collimator. The maximum dose was 150 Gy in the initial six cases, which was reduced to 130 Gy thereafter. The longest follow-up period was 6 years. The target was determined on T2-weighted and proton magnetic resonance (MR) images. The point chosen was in the lateral-most part of the thalamic ventralis intermedius nucleus. This is in keeping with open thalamotomy as practiced at the authors' institution. In 15 cases, gamma thalamotomy was the first surgical procedure. In other cases, previous therapeutic or vascular lesions were visible to facilitate targeting. Two types of tissue reaction were onserved on MR imaging: a simple oval shape and a complex irregular shape. Neither of these changes affected the clinical course. In the majority of cases, the tremor subsided after a latent interval of approximately 1 year after irradiation. The earliest response was demonstrated at 3 months. In five cases the tremor remained. In four of these cases, a second radiation session was administered. One of these four patients as well as another patient with an unsatisfactory result underwent open thalamotomy with microrecording. In both cases, depth recording adjacent to the necrotic area revealed normal neuronal activity, including the rhythmic discharge of tremor. Minor coagulation was performed and resulted in immediate and complete arrest of the remaining tremor. Conclusions. Gamma thalamotomy for Parkinson's disease seems to be an alternative useful method in selected cases.

Gamma knife radiosurgery as a single treatment modality for large cerebral arteriovenous malformations

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 113-119 ◽  
Author(s):  
D. Hung-Chi Pan ◽  
Wan-Yuo Guo ◽  
Wen-Yuh Chung ◽  
Cheng-Ying Shiau ◽  
Yue-Cune Chang ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Radiation Treatment ◽  
Gamma Knife Radiosurgery ◽  
Consecutive Series ◽  
Content Type ◽  
Obliteration Rate ◽  
Complete Obliteration ◽  
Fine Print

Object. A consecutive series of 240 patients with arteriovenous malformations (AVMs) treated by gamma knife radiosurgery (GKS) between March 1993 and March 1999 was evaluated to assess the efficacy and safety of radiosurgery for cerebral AVMs larger than 10 cm3 in volume. Methods. Seventy-six patients (32%) had AVM nidus volumes of more than 10 cm3. During radiosurgery, targeting and delineation of AVM nidi were based on integrated stereotactic magnetic resonance (MR) imaging and x-ray angiography. The radiation treatment was performed using multiple small isocenters to improve conformity of the treatment volume. The mean dose inside the nidus was kept between 20 Gy and 24 Gy. The margin dose ranged between 15 to 18 Gy placed at the 55 to 60% isodose centers. Follow up ranged from 12 to 73 months. There was complete obliteration in 24 patients with an AVM volume of more than 10 cm3 and in 91 patients with an AVM volume of less than 10 cm3. The latency for complete obliteration in larger-volume AVMs was significantly longer. In Kaplan—Meier analysis, the complete obliteration rate in 40 months was 77% in AVMs with volumes between 10 to 15 cm3, as compared with 25% for AVMs with a volume of more than 15 cm3. In the latter, the obliteration rate had increased to 58% at 50 months. The follow-up MR images revealed that large-volume AVMs had higher incidences of postradiosurgical edema, petechiae, and hemorrhage. The bleeding rate before cure was 9.2% (seven of 76) for AVMs with a volume exceeding 10 cm3, and 1.8% (three of 164) for AVMs with a volume less than 10 cm3. Although focal edema was more frequently found in large AVMs, most of the cases were reversible. Permanent neurological complications were found in 3.9% (three of 76) of the patients with an AVM volume of more than 10 cm3, 3.8% (three of 80) of those with AVM volume of 3 to 10 cm3, and 2.4% (two of 84) of those with an AVM volume less than 3 cm3. These differences in complications rate were not significant. Conclusions. Recent improvement of radiosurgery in conjunction with stereotactic MR targeting and multiplanar dose planning has permitted the treatment of larger AVMs. It is suggested that gamma knife radiosurgery is effective for treating AVMs as large as 30 cm3 in volume with an acceptable risk.

Factors related to complete occlusion of arteriovenous malformations after gamma knife radiosurgery

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 96-101 ◽  
Author(s):  
Jong Hee Chang ◽  
Jin Woo Chang ◽  
Yong Gou Park ◽  
Sang Sup Chung
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
Maximum Diameter ◽  
Content Type ◽  
Complete Occlusion ◽  
Factors Associated ◽  
Martin Grade ◽  
Fine Print

Object. The authors sought to evaluate the effects of gamma knife radiosurgery (GKS) on cerebral arteriovenous malformations (AVMs) and the factors associated with complete occlusion. Methods. A total of 301 radiosurgical procedures for 277 cerebral AVMs were performed between December 1988 and December 1999. Two hundred seventy-eight lesions in 254 patients who were treated with GKS from May 1992 to December 1999 were analyzed. Several clinical and radiological parameters were evaluated. Conclusions. The total obliteration rate for the cases with an adequate radiological follow up of more than 2 years was 78.9%. In multivariate analysis, maximum diameter, angiographically delineated shape of the AVM nidus, and the number of draining veins significantly influenced the result of radiosurgery. In addition, margin radiation dose, Spetzler—Martin grade, and the flow pattern of the AVM nidus also had some influence on the outcome. In addition to the size, topography, and radiosurgical parameters of AVMs, it would seem to be necessary to consider the angioarchitectural and hemodynamic aspects to select proper candidates for radiosurgery.

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