Preoperative stereotactic radiosurgery for cerebral metastases: safe, effective, and decreases steroid dependency.

Objective: Preoperative stereotactic radiosurgery (SRS) is emerging as a viable alternative to standard postoperative SRS. Studies have suggested that preoperative SRS provides comparable tumor control and overall survival (OS) and may reduce the incidence of leptomeningeal disease (LMD) and adverse radiation effects (AREs). It is unknown, however, if preoperative SRS remains effective in cohorts including large brain metastases (> 14 cm3) or if preoperative SRS affects steroid taper/immunotherapy.

Single isocenter HyperArc treatment of multiple intracranial metastases: Targeting accuracy.

Purpose/objectives: (A) To examine the alignment accuracy of CBCT guidance for brain metastases with off centered isocenters, (B) to test dose delivery and targeting accuracy for single isocenter treatments with multiple brain metastases. We report the results of the end-to-end test for Truebeam stereotactic radiosurgery (SRS).

Materials/methods: An anthropomorphic CT head phantom was drilled with five MOSFET inserts and two PTW Pinpoint chamber inserts.

A 3D correction method for predicting the readings of a PinPoint chamber on the CyberKnife M6 machine.

The use of small fields in radiation therapy techniques has increased substantially in particular in stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). However, as field size reduces further still, the response of the detector changes more rapidly with field size, and the effects of measurement uncertainties become increasingly significant due to the lack of lateral charged particle equilibrium, spectral changes as a function of field size, detector choice, and subsequent perturbations of the charged particle fluence. This work presents a novel 3D dose volume-to-point correction method to predict the readings of a 0.

Long-Term Survivorship Following Stereotactic Radiosurgery Alone for Brain Metastases: Risk of Intracranial Failure and Implications for Surveillance and Counseling.

Background: Historically, survival for even highly select cohorts of brain metastasis patients selected for SRS alone is <2 yr; thus, limited literature on risks of recurrence exists beyond 2 yr.

Objective: To investigate the possibility that for subsets of patients the risk of intracranial failure beyond 2 yr is less than the commonly quoted 50% to 60%, wherein less frequent screening may be appropriate.

Methods: As a part of our institutional radiosurgery database, we identified 132 patients treated initially with stereotactic radiosurgery (SRS) alone (± pre-SRS surgical resection) with at least 2 yr of survival and follow-up from SRS.

Dosimetric comparison between cone/Iris-based and InCise MLC-based CyberKnife plans for single and multiple brain metastases.

We performed an evaluation of the CyberKnife InCise MLC by comparing plan qualities for single and multiple brain lesions generated using the first version of InCise MLC, fixed cone, and Iris collimators. We also investigated differences in delivery efficiency among the three collimators. Twenty-four patients with single or multiple brain mets treated previously in our clinic on a CyberKnife M6 using cone/Iris collimators were selected for this study.

A method to improve dose gradient for robotic radiosurgery.

For targets with substantial volume, collimators of relatively large size are usually selected to minimize the treatment time in robotic radiosurgery. Their large penumbrae may adversely affect the dose gradient around the target. In this study, we implement and evaluate an inner-shell planning method to increase the dose gradient and reduce dose to normal tissues.

Stereotactic Radiosurgery/Stereotactic Body Radiotherapy for Recurrent Lung Neoplasm: An Analysis of Outcomes in 100 Patients.

Background: A significant number of patients have recurrent or persistent lung cancer despite complete resection or treatment with definitive chemoradiation. Stereotactic radiosurgery (SRS)/stereotactic body radiation therapy is emerging as an important modality for the treatment of early-stage lung neoplasm; SRS may also offer an alternative treatment option for patients with recurrent lung disease. We evaluated outcomes after treatment with SRS for recurrent lung neoplasm in a large series of patients.

Postoperative stereotactic radiosurgery to the resection cavity for large brain metastases: clinical outcomes, predictors of intracranial failure, and implications for optimal patient selection.

Background: Postoperative stereotactic radiosurgery for brain metastases potentially offers similar local control rates and fewer long-term neurocognitive sequelae compared to whole brain radiation therapy, although patients remain at risk for distant brain failure (DBF).

Objective: To describe clinical outcomes of adjuvant stereotactic radiosurgery for large brain metastases and identify predictors of intracranial failure and their implications on optimal patient selection criteria.

Methods: We performed a retrospective review on 100 large (>3 cm) brain metastases in 99 patients managed by resection followed by postoperative stereotactic radiosurgery to a median dose of 22 Gy (range, 10-28) in 1 to 5 fractions (median, 3).

Treatment outcomes in patients treated with CyberKnife radiosurgery for vestibular schwannoma.

Objective: To evaluate tumor control, hearing, tinnitus, and balance outcomes of patients treated with CyberKnife (CK) radiosurgery for vestibular schwannoma (VS).

Study Design: Retrospective series review.

Setting: Tertiary referral center.

Target delineation in stereotactic body radiation therapy for recurrent head and neck cancer: a retrospective analysis of the impact of margins and automated PET-CT segmentation.

Background: Few guidelines exist on stereotactic body radiation therapy (SBRT) treatment planning for recurrent head and neck cancer. We assessed the impact of retrospectively adding margins/automated PET volumes to the gross tumor volume (GTV) in patients with post-SBRT recurrences.

Materials And Methods: We reviewed 89 patients with recurrent head and neck cancer treated with SBRT using no margin around the GTV.

A retrospective, deformable registration analysis of the impact of PET-CT planning on patterns of failure in stereotactic body radiation therapy for recurrent head and neck cancer.

Background: Stereotactic body radiation therapy (SBRT) has seen increasing use as a salvage strategy for selected patients with recurrent, previously-irradiated squamous cell carcinoma of the head and neck (rSCCHN). PET-CT may be advantageous for tumor delineation and evaluation of treatment failures in SBRT. We analyzed the patterns of failure following SBRT for rSCCHN and assessed the impact of PET-CT treatment planning on these patterns of failure.

Stereotactic body radiotherapy for the treatment of presacral recurrences from rectal cancers.

Purpose: Management of recurrent presacral rectal cancer is often not amenable to curative surgery. The goal of this study is to evaluate the safety and efficacy of cyberknife stereotactic body radiotherapy (SBRT) in the management of presacral recurrences.

Materials And Methods: Between April 2003 and October 2008, 14 patients with presacral tumors from rectal adenocarcinoma were SBRT treated.

Stereotactic radiosurgery to the resection cavity of brain metastases: a retrospective analysis and literature review.

Purpose: The aim of this study was to analyze results of stereotactic radiosurgery (SRS) as adjuvant therapy for resected brain metastases.

Methods: Medical records of patients treated at a single institution with SRS to the postoperative cavity of brain metastases were retrospectively reviewed. Patients who completed the prescribed SRS regimen following gross-total resection and had no previous whole brain radiotherapy were included in the study.

The impact of tumor volume and radiotherapy dose on outcome in previously irradiated recurrent squamous cell carcinoma of the head and neck treated with stereotactic body radiation therapy.

Purpose: To assess the effect of stereotactic body radiotherapy (SBRT) dose and tumor volume on outcomes in patients with recurrent, previously irradiated squamous cell carcinoma of the head and neck.

Materials And Methods: A total of 96 patients with recurrent, previously irradiated squamous cell carcinoma of the head and neck were treated with SBRT using Cyberknife and Trilogy-intensity-modulated radiosurgery. Kaplan-Meier survival analyses were used to estimate locoregional control (LRC) and overall survival rates.

Combined endoscopic endonasal surgery and fractionated stereotactic radiosurgery (fSRS) for complex cranial base tumors-early clinical outcomes.

Endoscopic endonasal surgery (EES) has been shown to be a feasible approach to cranial base tumors while reducing post-operative morbidity. Using the endoscopic endonasal approach alone or in combination with open approaches may provide advantages over conventional approaches. However, the balance between maximal resection and minimal injury to neurovascular structures frequently precludes gross total resection (GTR).

Fractionated stereotactic body radiation therapy in the treatment of previously-irradiated recurrent head and neck carcinoma: updated report of the University of Pittsburgh experience.

Objectives: The aim of this study was to assess the safety and outcome of stereotactic body radiotherapy (SBRT) in patients with recurrent previously irradiated squamous cell carcinoma of the head and neck (rSCCHN).

Methods: We reviewed our experience with 85 patients who received SBRT for rSCCHN between January 2003 and May 2008. The mean dose of SBRT was 35 Gy (range: 15-44 Gy).

Stereotactic radiosurgery for the treatment of lung neoplasm: experience in 100 consecutive patients.

Background: Surgical resection is the standard of care for patients with resectable non-small cell lung cancer or selected patients with pulmonary metastases. Stereotactic radiosurgery may offer an alternative option for high-risk patients who are not surgical candidates. We report our initial experience with stereotactic radiosurgery in the treatment of lung neoplasm in 100 consecutive patients.

Stereotactic radiosurgery for the treatment of stage I non-small cell lung cancer in high-risk patients.

Objective: Surgical resection is the standard of care for patients with stage I non-small cell lung cancer. For high-risk patients, however, stereotactic radiosurgery may offer an alternative. We report our initial experience with stereotactic radiosurgery for treatment of stage I non-small cell lung cancer by a team of thoracic surgeons and radiation oncologists.

Fractionated stereotactic body radiation therapy in the treatment of primary, recurrent, and metastatic lung tumors: the role of positron emission tomography/computed tomography-based treatment planning.

Purpose: The aim of this study was to assess the outcomes of patients treated with stereotactic body radiation therapy (SBRT) in patients with primary, recurrent, or metastatic lung lesions, with a focus on positron emission tomography (PET)/computed tomography (CT)-based management.

Patients And Methods: Fifty-one patients with primary stage I non-small-cell lung cancer (NSCLC; n = 26), recurrent lung cancer after definitive treatment (n = 12), or solitary lung metastases (n = 13) were treated with SBRT between 2005 and 2007. Patients were treated with the CyberKnife Robotic Radiosurgery System with Synchrony respiratory tracking.

Radiosurgery for benign intradural spinal tumors.

Objective: The role of stereotactic radiosurgery for the treatment of intracranial benign tumors is well established. There is less experience and more controversy regarding its use for benign tumors of the spine. This study evaluated the clinical efficacy of radiosurgery as part of the treatment paradigm of selected benign tumors of the spine.

Synchrony--cyberknife respiratory compensation technology.

Studies of organs in the thorax and abdomen have shown that these organs can move as much as 40 mm due to respiratory motion. Without compensation for this motion during the course of external beam radiation therapy, the dose coverage to target may be compromised. On the other hand, if compensation of this motion is by expansion of the margin around the target, a significant volume of normal tissue may be unnecessarily irradiated.

Stereotactic radiosurgery for the treatment of lung neoplasm: initial experience.

Background: Surgical resection is the standard of care for patients with resectable non-small cell lung carcinoma (NSCLC) or limited pulmonary metastases. Stereotactic radiosurgery (SRS) may offer an alternative option for high-risk patients who are not surgical candidates. We report our initial experience with SRS in the treatment of lung neoplasm.

Intra-fraction dose delivery timing during stereotactic radiotherapy can influence the radiobiological effect.

The sequence of incremental dose delivery during a radiotherapy fraction can potentially influence the radiobiological effect. This would be most noticeable during the long fractions characteristic of hypo-fractionated stereotactic radiotherapy and radiosurgery. We demonstrate here the spatio-temporal variation of dose delivery by the CyberKnife to a lung tumor and propose strategies to reduce and/or correct for any resultant dose-time cytotoxic effects.

CyberKnife radiosurgery for spinal neoplasms.

The role of stereotactic radiosurgery for the treatment of intracranial lesions is well established. Its use for the treatment of spinal lesions has been limited by the availability of effective target immobilization and localization technologies. Conventional external beam radiotherapy lacks the precision to allow delivery of large doses of radiation near radiosensitive structures such as the spinal cord.

Radiosurgery for spinal metastases: clinical experience in 500 cases from a single institution.

Study Design: A prospective nonrandomized, longitudinal cohort study.

Objective: To evaluate the clinical outcomes of single-fraction radiosurgery as part of the management of metastatic spine tumors.

Summary Of Background Data: The role of stereotactic radiosurgery for the treatment of spinal lesions has previously been limited by the availability of effective target immobilization and target tracking devices.