1,721,152 research outputs found
Technical advances in radiation therapy for brain tumors
Full text linkRadiation therapy plays a critical role in the management of brain tumors. Recent advances in radiation techniques include the use of intensity-modulated radiotherapy (IMRT), volumetric-modulated arc therapy (VMAT) and stereotactic radiosurgery (SRS). All of these techniques allow the delivery of higher radiation doses to the target volume, at the same time reducing the risk of toxicity to normal tissues as compared with conventional 3D conformal radiotherapy (3D-CRT). Proton therapy may represent a treatment alternative to photon irradiation, due to the more favorable dose distribution to the target volume. This review summarizes current developments in radiation therapy and their clinical impact on the management of patients with brain tumors
Single- Versus Multiple-Fraction Stereotactic Radiotherapy
No full textAlthough surgical excision is the treatment of choice for accessible skull base meningiomas, a significant subset of complex tumours tightly attached to or encasing neurovascular structures cannot be removed safely via surgery alone. In patients with residual or progressing disease after incomplete tumour resection, adjuvant external beam radiation therapy (RT) has traditionally been employed, with a reported local tumour control rate of up to 90% at 10 years. In recent decades, RT has evolved to encompass conformal and stereotactic techniques. The dramatic technical advances in all aspects of treatment have led to better immobilization, imaging, planning, and treatment. Advanced radio-oncology techniques include intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT), and stereotactic radiotherapy (SRT) and radiosurgery (SRS), which allow for more precise dose delivery to the tumour while limiting the amount of radiation to the sensitive brain structures, i.e. the optic pathway and the brainstem. New radiation techniques, particularly SRS, have progressively emerged as effective primary treatments for selected meningiomas of the skull base. Large series demonstrate local control rates of over 90% at 5 years following SRS, and above 80% at 10–15 years. Although virtually non-invasive, SRS carries a risk of late radiation-induced toxicity, typically cranial nerve deficits causing impaired visual acuity and ocular motility. For patients with large skull base meningiomas or tumours in close proximity to the optic pathway, fractionated SRS (2–5 fractions) has emerged as an alternative to single-fraction SRS, with the hope of reducing the long-term consequences of treatment while maintaining its effectiveness. Currently, SRT and SRS are an essential part of the modern management of skull base meningiomas recurring after surgery or in difficult-to-access locations
Tumors of the Optic Nerve and Its Sheath
No full textThe tumors of the optic nerve may arise from the nerve itself or from its sheath. Benign gliomas and meningiomas are the most frequent types, whereas other histological types are exceptional. Benign tumors cause slowly progressive visual loss and variable proptosis. The radiological diagnosis is rather easy for gliomas and meningiomas. The observation is justified in patients with preserved or stable vision. The surgery is often delayed because of the significant risk of visual worsening. Pediatric benign gliomas often respond to chemotherapy. Patients with optic nerve sheath meningiomas may be treated by stereotactic radiosurgery. However, the visual prognosis is more often poor. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023
Long term follow up of radionecrotic brain metastases assessed by serial F-DOPA PET/CT scans
No full textStereotactic radiotherapy and radiosurgery for non-functioning and secreting pituitary adenomas
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Skull Base Meningiomas
No full textSurgical excision is the treatment of choice for accessible skull base meningiomas. Nevertheless, a significant subset of complex tumors tightly attached to or encasing neurovascular structures cannot be removed safely. In such patients with residual or progressing disease after incomplete tumor resection, adjuvant external beam radiation therapy (RT) has been traditionally employed with a reported tumor local control up to 90% at 10 years. In the last decades, RT has evolved with the development of conformal and stereotactic techniques with dramatic technical advances in all aspects of treatment with better immobilization, imaging, planning, and treatment. Advanced radio-oncology techniques include intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT), and stereotactic radiotherapy (SRT) and radiosurgery (SRS) which allow for more precise dose delivery to the tumor while limiting the amount of radiation to the sensitive brain structures, i.e., the optic pathway and the brainstem. New radiation techniques, particularly SRS, have progressively emerged as an effective primary treatment of selected meningiomas of the skull base. Large series report local control rates of more than 90% at 5 years following SRS, which remain above 80% at 10–15 years. Although virtually noninvasive, SRS carries a risk of radiation-induced late toxicity, typically cranial nerve deficits causing impaired visual acuity and ocular motility. For patients with large skull base meningiomas or with tumors in close proximity to the optic pathway, fractionated SRS (2–5 fractions) has emerged as an alternative to single-fraction SRS with the hope of reducing the long-term consequences of treatment while maintaining its effectiveness. Currently, SRT and SRS are an essential part of the modern management of skull base meningiomas recurring after surgery or located at difficult accessibility
Target delineation and optimal radiosurgical dose for pituitary tumors
Full text linkStereotactic radiosurgery (SRS) delivered as either single-fraction or multi-fraction SRS (2-5 fractions) is frequently employed in patients with residual or recurrent pituitary adenoma. The most common delivery systems used for SRS include the cobalt-60 system Gamma Knife, the CyberKnife (CK) robotic radiosurgery system, or a modified conventional radiotherapy machine (linear accelerator, LINAC). Tumor control and normalization of hormone hypersecretion have been reported in 75-100 % and 25-80 % of patients, respectively. Hypopituitarism is the most commonly reported late complication of radiation treatment, whereas other toxicities occur less frequently. We have provided an overview of the recent available literature on SRS in patients with a pituitary adenoma. Critical aspects of pituitary irradiation, including target delineation and doses to organs at risk, optimal radiation dose, as well as the long-term efficacy and toxicity of SRS for either nonfunctioning or secreting pituitary adenomas are discussed. Single-fraction SRS represents an effective treatment for patients with a pituitary adenoma; however, caution should be used for lesions > 2.5-3 cm in size and/or involving the anterior optic pathway. Future studies will be necessary to optimize target doses and critical organ dose constrains in order to reduce the long-term toxicity of treatments while maintaining high efficacy.
KEYWORDS:
Acromegaly; Cushing’s disease; Fractionated stereotactic radiotherapy; Pituitary adenoma; Radiosurgery; Target delineatio
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