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Barber SM, Teh BS, Baskin DS. Fractionated Stereotactic Radiotherapy for Pituitary Adenomas: Single-Center Experience in 75 Consecutive Patients. Neurosurgery 2017; 79:406-17. [PMID: 26657072 DOI: 10.1227/neu.0000000000001155] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Early results of postoperative fractionated stereotactic radiotherapy (FSRT) for functional and nonfunctional pituitary adenomas appear promising, but the majority of available evidence draws from small series with insufficient follow-up data to draw meaningful conclusions. OBJECTIVE To evaluate the long-term outcomes of a large series of patients undergoing FSRT for both functional and nonfunctional pituitary adenomas with the Novalis system (BrainLAB, Heimstetten, Germany). METHODS Chart data for 75 consecutive patients undergoing FSRT for a pituitary tumor (21 functional and 54 nonfunctional adenomas) at our institution between January 2004 and June 2013 were reviewed. RESULTS Radiographic progression-free survival was 100% over a mean of 47.8 months of radiographic follow-up (range, 12.0-131.2 months). Hormonal normalization was seen in 69.2% of patients with functional adenomas after FSRT, whereas 30.8% experienced partial hormonal control. Mild, grade I acute adverse effects were observed during radiotherapy treatment in 36 patients (48%), and objective, persistent worsening of vision occurred in a single patient (1.5%) after FSRT. New hormonal deficits were seen in 28.0% of patients after FSRT. Radiographic responses were inversely related to tumor volume. CONCLUSION FSRT delivers radiographic and functional outcomes similar to those seen with stereotactic radiosurgery and conventional radiotherapy with less resultant toxicity. FSRT is most beneficial for smaller tumors (those <3 cm in diameter). ABBREVIATIONS EBRT, external beam radiotherapyFSRT, fractionated stereotactic radiotherapyOR, odds ratioPTV, planning target volumeSRS, stereotactic radiosurgery.
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Affiliation(s)
- Sean M Barber
- *Houston Methodist Neurological Institute, Department of Neurological Surgery, Houston Methodist Hospital, Houston, Texas; ‡Department of Radiation Oncology, Houston Methodist Hospital, Houston, Texas; §Kenneth R. Peak Brain and Pituitary Tumor Treatment Center, Houston Methodist Hospital, Houston, Texas
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Clarke RH, Moosa S, Anzivino M, Wang Y, Floyd DH, Purow BW, Lee KS. Sustained radiosensitization of hypoxic glioma cells after oxygen pretreatment in an animal model of glioblastoma and in vitro models of tumor hypoxia. PLoS One 2014; 9:e111199. [PMID: 25350400 PMCID: PMC4211739 DOI: 10.1371/journal.pone.0111199] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/29/2014] [Indexed: 12/31/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most common and lethal form of brain cancer and these tumors are highly resistant to chemo- and radiotherapy. Radioresistance is thought to result from a paucity of molecular oxygen in hypoxic tumor regions, resulting in reduced DNA damage and enhanced cellular defense mechanisms. Efforts to counteract tumor hypoxia during radiotherapy are limited by an attendant increase in the sensitivity of healthy brain tissue to radiation. However, the presence of heightened levels of molecular oxygen during radiotherapy, while conventionally deemed critical for adjuvant oxygen therapy to sensitize hypoxic tumor tissue, might not actually be necessary. We evaluated the concept that pre-treating tumor tissue by transiently elevating tissue oxygenation prior to radiation exposure could increase the efficacy of radiotherapy, even when radiotherapy is administered after the return of tumor tissue oxygen to hypoxic baseline levels. Using nude mice bearing intracranial U87-luciferase xenografts, and in vitro models of tumor hypoxia, the efficacy of oxygen pretreatment for producing radiosensitization was tested. Oxygen-induced radiosensitization of tumor tissue was observed in GBM xenografts, as seen by suppression of tumor growth and increased survival. Additionally, rodent and human glioma cells, and human glioma stem cells, exhibited prolonged enhanced vulnerability to radiation after oxygen pretreatment in vitro, even when radiation was delivered under hypoxic conditions. Over-expression of HIF-1α reduced this radiosensitization, indicating that this effect is mediated, in part, via a change in HIF-1-dependent mechanisms. Importantly, an identical duration of transient hyperoxic exposure does not sensitize normal human astrocytes to radiation in vitro. Taken together, these results indicate that briefly pre-treating tumors with elevated levels of oxygen prior to radiotherapy may represent a means for selectively targeting radiation-resistant hypoxic cancer cells, and could serve as a safe and effective adjuvant to radiation therapy for patients with GBM.
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Affiliation(s)
- Ryon H. Clarke
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States of America
- School of Medicine, University of Virginia Health System, Charlottesville, VA, United States of America
| | - Shayan Moosa
- School of Medicine, University of Virginia Health System, Charlottesville, VA, United States of America
| | - Matthew Anzivino
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States of America
- School of Medicine, University of Virginia Health System, Charlottesville, VA, United States of America
| | - Yi Wang
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States of America
- School of Medicine, University of Virginia Health System, Charlottesville, VA, United States of America
| | - Desiree Hunt Floyd
- School of Medicine, University of Virginia Health System, Charlottesville, VA, United States of America
- Division of Neuro-Oncology, Departments of Neurology, Microbiology, and Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA, United States of America
| | - Benjamin W. Purow
- School of Medicine, University of Virginia Health System, Charlottesville, VA, United States of America
- Division of Neuro-Oncology, Departments of Neurology, Microbiology, and Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA, United States of America
| | - Kevin S. Lee
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States of America
- School of Medicine, University of Virginia Health System, Charlottesville, VA, United States of America
- Department of Neurological Surgery, University of Virginia, Charlottesville, VA, United States of America
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Jensen RL, Wendland MM, Chern SS, Shrieve DC. Novalis intensity-modulated radiosurgery: methods for pretreatment planning. Neurosurgery 2008; 62:A2-9; discussion A9-10. [PMID: 18580777 DOI: 10.1227/01.neu.0000325931.26531.45] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE The Novalis stereotactic radiotherapy system (BrainLAB, Heimstetten, Germany) allows for precise treatment of cranial base tumors with single-fraction radiosurgery. In some cases, however, proximity of the optic nerve and chiasm is a concern. In these cases, intensity-modulated stereotactic radiosurgery (IMRS) can be used to limit the dose to these structures. IMRS planning can be labor intensive, which poses a problem when it is performed on the day of treatment. We describe our methods and results of preprocedure planning for IMRS for patients with lesions in the cavernous sinus or parasellar regions in whom the dose to the optic nerve or chiasm might exceed our acceptable tolerance dose (8 Gy). METHODS Patients whose lesions were more than 4 mm from the optic nerve and chiasm on standard magnetic resonance imaging scans but who were questionable candidates for radiosurgery because of concerns of dose to the optic nerve or chiasm were considered for IMRS. Preprocedure imaging (computed tomography and magnetic resonance imaging) was fused and analyzed using the BrainLAB BrainScan 5.3 treatment planning system. Dynamic conformal arc plans for stereotactic radiosurgery and IMRS were evaluated. Doses to the planning target volume and optic apparatus were assessed by dose-volume histograms and conformality index calculated to characterize the quality of the different plans. When IMRS was used, the preplan allowed for a rapid recalculation on the treatment day, minimizing the time patients were in the head frame before treatment. RESULTS We describe three patients with recurrent pituitary tumors and three with meningiomas. Doses were 1500 to 2000 cGy prescribed to the 80 to 96% isodose line delivered by eight to 22 fields. Tumor volumes ranged from 2.70 to 8.82 cm (mean, 5.7 cm). In five of the six patients, the dynamic conformal arc plan precluded delivery of therapeutic dose without exceeding optic nerve tolerance. On the basis of 95% coverage of target volume, maximum prescription doses of 7.7 to 20.64 Gy were possible with the dynamic conformal arc plans without exceeding 8 Gy to the optic apparatus. IMRS allowed maximum doses of 20 to 31 Gy using the same optic apparatus dose restriction. No complications have occurred, and all tumors have remained stable since treatment (mean follow-up period, 30 mo). CONCLUSION We believe this pretreatment technique streamlines the process for IMRS, allowing for better patient comfort and efficient physician time use.
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Affiliation(s)
- Randy L Jensen
- Department of Neurosurgery, The Huntsman Cancer Institute, University of Utah Health Sciences Center, Salt Lake City, Utah, USA.
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Jagannathan J, Sherman JH, Mehta GU, Chin LS. Radiobiology of brain metastasis: applications in stereotactic radiosurgery. Neurosurg Focus 2007; 22:E4. [PMID: 17608357 DOI: 10.3171/foc.2007.22.3.5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Stereotactic radiosurgery is a neurosurgical modality in which a target lesion can be irradiated while sparing normal brain tissue. In some respects, brain metastasis is well suited for radiosurgery, as metastatic lesions tend to be small and well circumscribed and displace (but do not infiltrate) normal brain tissue, facilitating the delivery of radiation. Advances in stereotactic radiosurgical planning, such as blocking patterns and beam shaping, have allowed further targeting of discrete lesions while minimizing the effect of radiation toxicity on the central nervous system. In this paper the authors review the radiobiology of brain metastases and stereotactic radiosurgical approaches that can be used to treat these tumors safely.
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Affiliation(s)
- Jay Jagannathan
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia 22908, USA.
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