Cihat Ozhasoglu

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. Large clinical experience with spinal radiosurgery to properly assess clinical experience has previously been limited. Methods. A cohort of 500 cases of spinal metastases underwent radiosurgery. Ages ranged from 18 to 85 years (mean 56). Lesion location included 73 cervical, 212 thoracic, 112 lumbar, and 103 sacral. Results. The maximum intratumoral dose ranged from 12.5 to 25 Gy (mean 20). Tumor volume ranged from 0.20 to 264 mL (mean 46). Long-term pain improvement occurred in 290 of 336 cases (86%). Long-term tumor control was demonstrated in 90% of lesions treated with radiosurgery as a primary treatment modality and in 88% of lesions treated for radiographic tumor progression. Twenty-seven of 32 cases (84%) with a progressive neurologic deficit before treatment experienced at least some clinical improvement. Conclusions. The results indicate the potential of radiosurgery in the treatment of patients with spinal metastases, especially those with solitary sites of spine involvement, to improve long-term palliation.

CyberKnife Frameless Stereotactic Radiosurgery for Spinal Lesions: Clinical Experience in 125 Cases

OBJECTIVE: 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 targe-immobilizing devices. Conventional external beam radiotherapy lacks the precision to allow delivery of large doses of radiation near radiosensitive structures such as the spinal cord. The CyberKnife (Accuray, Inc., Sunnyvale, CA) is an image-guided frameless stereotactic radiosurgery system that allows for the radiosurgical treatment of spinal lesions. This study evaluated the feasibility and effectiveness of the treatment of spinal lesions with a single-fraction radiosurgical technique using the CyberKnife. METHODS: The CyberKnife system uses the coupling of an orthogonal pair of x-ray cameras to a dynamically manipulated robot-mounted linear accelerator with six degrees of freedom that guides the therapy beam to the intended target without the use of frame-based fixation. Real-time imaging allows the tracking of patient movement. Cervical spine lesions were located and tracked relative to cranial bony landmarks lower spinal lesions were tracked relative to fiducial bone markers. In this prospective cohort evaluation of a spine radiosurgery technique, 125 spinal lesions in 115 consecutive patients were treated with a single-fraction radiosurgery technique (45 cervical, 30 thoracic, 36 lumbar, and 14 sacral). There were 17 benign tumors and 108 metastatic lesions. All dose plans were calculated on the basis of computed tomographic images acquired from 1.25-mm slices with an inverse treatment planning technique. Radiosurgical circular cones ranging in diameter from 5 to 40 mm were used. RESULTS: Tumor volume ranged from 0l3 to 232 cm 3 (mean, 27.8 cm 3 ). Seventy-eight lesions had received external beam irradiation previously. Tumor dose was maintained at 12 to 20 Cy to the 80% isodose line (mean, 14 Gy); canal volume receiving more than 8 Gy ranged from 0.0 to 1.7 cm 3 (mean, 0.2 cm 3 ). No acute radiation toxicity or new neurological deficits occurred during the follow up period (range, 9-30 mo median, 18 mo). Axial and radicular pain improved in 74 of 79 patients who were symptomatic before treatment. CONCLUSION: This is the first large prospective evaluation of this frameless imageguided spinal radiosurgery system. The Cyberknife system was found to be feasbile, safe, and effective. The major potential benetits of radiosurgical ablation of spinal lesions are short treatment time in an outpatient setting with rapid recovery and symptomatic response. This technique offers a successial therapeutic modality for the treatment of a variety of spinal lesions as a primary treatment or for lesions not amenable to open surgical techniques, in medically inoperable patients, in lesions located in previously irradiated sites or as an adjunct to surgery.

Combination kyphoplasty and spinal radiosurgery: a new treatment paradigm for pathological fractures

OBJECT Patients with symptomatic pathological compression fractures require spinal stabilization surgery for mechanical back pain control and irradiation for the underlying malignant process. The authors evaluated a treatment paradigm of closed fracture reduction and fixation involving kyphoplasty and subsequent spinal radiosurgery. METHODS Twenty-six patients (six men and 20 women, mean age 72 years) with pathological compression fractures (16 thoracic and 10 lumbar) were prospectively evaluated. Histological diagnoses included 11 lung, nine breast, four renal, one cholangiocarcioma, and one ocular melanoma. Seven lesions had received prior external-beam radiation therapy. All patients underwent kyphoplasty that involved the percutaneous transpedicular technique. Fiducial markers allowing for image guidance during CyberKnife treatment were placed, at time of the kyphoplasty, in the pedicles at adjacent levels. Patients underwent single-fraction radiosurgery (mean time after kyphoplasty 12 days) in an outpatient setting. The tumor dose was maintained at 16 to 20 Gy (mean 18 Gy) to the 80% isodose line. The treated tumor volume ranged from 12.7 to 37.1 cm3. No acute radiation-induced toxicity or new neurological deficit occurred during the follow-up period (range 11-24 months, median 16 months). Axial pain improved in 24 (92%) of 26 patients. CONCLUSIONS The combined kyphoplasty and spinal radiosurgery treatment paradigm was found to be clinically effective in patients with pathological fractures; there was no significant spinal canal compromise. In this technique two minimally invasive surgical procedures are combined to avoid the morbidity associated with open surgery while providing both immediate fracture fixation and administering a single-fraction tumoricidal radiation dose.

Single-fraction radiosurgery for the treatment of spinal breast metastases

The spine is the most common site of bony metastases in patients with osseous breast carcinoma metastases. Spine metastases are the source of significant pain and occasionally neurologic deficit in this patient population. Conventional external beam radiotherapy lacks the precision to allow delivery of large single‐fraction doses of radiation and simultaneously limit the dose to radiosensitive structures such as the spinal cord. This study evaluated the clinical efficacy of the treatment of spinal breast carcinoma metastases with a single‐fraction radiosurgical technique.

RADIOSURGERY FOR BENIGN INTRADURAL SPINAL TUMORS

OBJECTIVEThe 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. METHODSSeventy-three benign intradural extramedullary spinal tumors were treated with a radiosurgery technique and prospectively evaluated. Patient ages ranged from 18 to 85 years (mean age, 44 yr); the follow-up period was 8 to 71 months (median, 37 mo). Lesion location included 43 cervical, five thoracic, 19 lumbar, and six sacral. Tumor histology included neurofibroma (25 cases), schwannoma (35 cases), and meningioma (13 cases). Twenty-one cases were associated with neurofibromatosis Type 1, and nine patients had neurofibromatosis Type 2. Nineteen tumors (26%) had previously undergone open surgical resection, and six tumors (8%) had previously been treated with conventional external beam irradiation techniques. RESULTSSimilar radiation doses were prescribed for all three histopathologies. The maximum intratumoral dose was 1500 to 2500 cGy (mean, 2164 Gy). Tumor volume ranged from 0.3 to 93.4 cm3 (mean, 10.5 cm3; median, 4.11 cm3). Radiosurgery was used for the treatment of postsurgical radiographic progression in 18 cases; it was used as the primary treatment modality in 14 cases; it was used for treatment of radiographic tumor progression in nine cases; and it was used for the treatment of postsurgical residual tumor in two cases. Long-term pain improvement occurred in 22 out of 30 cases (73%). Long-term radiographic tumor control was demonstrated in all cases. Three patients experienced new symptoms attributed to radiation-induced spinal cord toxicity 5 to 13 months after treatment. CONCLUSIONSingle fraction radiosurgery was found to be clinically effective for the treatment of benign extramedullary spinal neoplasms. Although surgical extirpation remains the primary treatment option for most benign spinal tumors, radiosurgery was demonstrated to have short-term clinical benefits for the treatment of such lesions. The long-term efficacy of spinal radiosurgery for such tumors will be determined with longer follow-up periods. Its role in patients with neurofibromatosis will also be further defined with greater clinical experience.

Frameless stereotactic radiosurgery for recurrent head and neck carcinoma.

The aim of this study was to assess the feasibility and toxicity of stereotactic radiosurgery (CK-SRS) using the CyberKnife® Frameless Radiosurgery System (Accuray Inc., Sunnyvale, CA) in the management of recurrent squamous cell carcinoma of the head and neck region (SCCHN). Between November 2001 and February 2004, 22 patients with recurrent, previously irradiated SCCHN were treated with CK-SRS. The following endpoints were assessed post-CK-SRS: local control (LC), cause-specific survival (CSS), overall survival (OS), symptom relief, and acute and late toxicity. Kaplan-Meier survival analyses were used to estimate the LC, CSS, and OS rates. Clinical symptoms were graded as “improved,” “stable,” or “progressed” after CK-SRS. Acute and late toxicity were graded according to the National Cancer Institute Common Toxicity Criteria (CTC) scale, version 2.0. Seventeen patients were followed until their death. The median follow-up in the remaining five patients was 19 months (range 11–40 months). The median survival time for the entire cohort was 12 months from the time of CK-SRS. The 2-year LC, CSS, and OS rates were 26%, 26%, and 22%, respectively. After CK-SRS, symptoms were improved or stable in all but one patient who reported increasing pain. The treatment was well tolerated, with one case each of Grade 2 and 3 mucositis. There were no acute Grade 4 or 5 CTC toxicities. There were no late toxicities in this cohort. Frameless stereotactic radiosurgery for recurrent SCCHN is feasible and safe in the setting of high doses of prior irradiation. The majority of patients experienced palliation of disease without excess toxicity.

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. A dose of 60 Gy was delivered in 3 fractions. All patients had CT or PET/CT performed at approximately 3-month intervals after treatment. RESULTS The median follow-up was 12 months. Local control at median follow-up was 85% in patients with stage I NSCLC, 92% in patients with recurrent lung cancer, and 62% in the patients with solitary lung metastasis. Analysis of the 28 patients with pre- and post-treatment PET/CT scans demonstrated that those with stable disease (n = 4) had a mean standardized uptake value (SUV) decrease of 28%, partial responders (n = 11) had a decrease of 48%, and patients with a complete response (n = 11) had a decrease of 94%. Patients with progressive disease (n = 2) had an SUV decrease of only 0.4%. Only 2 patients (7%) who had reduced fluorodeoxyglucose avidity later progressed locally. No correlations were found between pretreatment SUV and tumor response, disease progression, or survival. Overall 1-year survival rates were 81%, 67%, and 85% among the patients with primary NSCLC, recurrent lung cancer, and solitary lung metastases, respectively. CONCLUSION Stereotactic body radiation therapy with CyberKnife is an effective treatment for patients with medically inoperable recurrent or metastatic lung cancer. Positron emission tomography/CT is valuable in staging, planning, and evaluating treatment response and might predict long-term outcome.

Evaluation of CyberKnife Frameless Real-Time Image-Guided Stereotactic Radiosurgery for Spinal Lesions

Background: This study evaluated the CyberKnife frameless image-guided radiosurgery system for the treatment of spinal lesions. Methods: This system utilizes the coupling of an orthogonal pair of X-ray cameras to a dynamically manipulated robot-mounted linear accelerator that guides the therapy beam to the intended target without the use of frame-based fixation. Cervical spine lesions are located and tracked relative to skull bony landmarks; lower spinal lesions are tracked relative to fiducial markers. 125 spinal lesions in 115 consecutive patients were treated with a single-fraction radiosurgery technique. Results: Tumor volume ranged from 0.3 to 232 ml (mean 27.8 ml). Tumor radiation dose was maintained at 12–20 Gy to the 80% isodose line (mean 14 Gy); the spinal cord or canal volume receiving greater than 8 Gy ranged from 0.0 to 1.7 ml (mean 0.2 ml). No acute radiation toxicity or new neurological deficits occurred during the follow-up period (3–24 months). Conclusions: The CyberKnife system was found to be feasible, safe and effective. The major potential benefits of radiosurgical ablation of spinal lesions are short treatment time in an outpatient setting with rapid recovery and good response.

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. Response was evaluated using positron emission tomography/computed tomography or computed tomography and detailed physical examination. Results:The median follow-up for all patients was 14 months (2–39 months). The median dose of prior radiation was 68.4 Gy (32–170 Gy). Patients were divided into 4 SBRT dose groups: I (15–28 Gy/n = 29), II (30–36 Gy/n = 22), III (40 Gy/n = 18), and IV (44–50 Gy/n = 27). The median gross tumor volume (GTV) was 24.3 cm3 (2.5–162 cm3). For GTV ≤25 cm3 (n = 50), complete response rates were 27.8%/30%/45.5%/45.5%, and for GTV >25 cm3 (n = 46), complete response rates were 20%/25%/42.8%/50% for SBRT groups I–IV, respectively. The 1-/2-/3-year LRC rates for doses 40 to 50 Gy were 69.4%/57.8%/41.1%, respectively, whereas for 15 to 36 Gy, they were 51.9%/31.7%/15.9%, respectively (P = 0.02). The overall 1- and 2-year overall survival rates were 58.9% and 28.4%, respectively. Treatment was well tolerated with no grade 4/5 toxicities. Conclusions:Dose escalation up to 50 Gy in 5 fractions is feasible with SBRT for recurrent head and neck squamous cell carcinoma. Higher SBRT doses were associated with significantly higher LRC rates. Large tumor volume required higher SBRT doses to achieve optimal response rates compared with smaller tumor volume.

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. In hypofractionated regimens, the issue of respiratory compensation becomes an important factor and is critical in single-fraction extracranial radiosurgery applications. CyberKnife is an image-guided radiosurgery system that consists of a 6-MV LINAC mounted to a robotic arm coupled through a control loop to a digital diagnostic x-ray imaging system. The robotic arm can point the beam anywhere in space with 6 degrees of freedom, without being constrained to a conventional isocenter. The CyberKnife has been recently upgraded with a real-time respiratory tracking and compensation system called Synchrony. Using external markers in conjunction with diagnostic x-ray images, Synchrony helps guide the robotic arm to move the radiation beam in real time such that the beam always remains aligned with the target. With the aid of Synchrony, the tumor motion can be tracked in three-dimensional space, and the motion-induced dosimetric change to target can be minimized with a limited margin. The working principles, advantages, limitations, and our clinical experience with this new technology will be discussed.