Single-fraction Stereotactic Body Research Articles

Dose-Escalation Study of Single-Fraction Stereotactic Body Radiotherapy for Liver Malignancies

We performed a Phase I dose-escalation study to explore the feasibility and safety of treating primary and metastatic liver tumors with single-fraction stereotactic body radiotherapy (SBRT). Between February 2004 and February 2008, 26 patients were treated for 40 identifiable lesions. Nineteen patients had hepatic metastases, 5 had intrahepatic cholangiocarcinomas, and 2 had recurrent hepatocellular carcinomas. The prescribed radiation dose was escalated from 18 to 30 Gy at 4-Gy increments with a planned maximum dose of 30 Gy. Cumulative incidence functions accounted for competing risks to estimate local failure (LF) incidence over time under the competing risk of death. All patients tolerated the single-fraction SBRT well without developing a dose-limiting toxicity. Nine acute Grade 1 toxicities, one acute Grade 2 toxicity, and two late Grade 2 gastrointestinal toxicities were observed. After a median of 17 months follow-up (range, 2-55 months), the cumulative risk of LF at 12 months was 23%. Fifteen patients have died: 11 treated for liver metastases and 4 with primary liver tumors died. The median survival was 28.6 months, and the 2-year actuarial overall survival was 50.4%. It is feasible and safe to deliver single-fraction, high-dose SBRT to primary or metastatic liver malignancies measuring ≤5 cm. Moreover, single-fraction SBRT for liver lesions demonstrated promising local tumor control with minimal acute and long-term toxicity. Single-fraction SBRT appears to be a viable nonsurgical option, but further studies are warranted to evaluate both control rates and impact on quality of life.

Low rate of thoracic toxicity in palliative paraspinal single fraction stereotactic body radiation therapy

Background There has been an increase in the utilization of single-fraction stereotactic body radiation therapy (SBRT) to treat thoracic structures, but there have been few reports describing toxicity outcomes with this treatment.

Low rate of thoracic toxicity in palliative paraspinal single-fraction stereotactic body radiation therapy

Background There has been an increase in the utilization of single-fraction stereotactic body radiation therapy (SBRT) to treat thoracic structures, but there have been few reports describing toxicity outcomes with this treatment. Methods We evaluated 119 sites (114 patients) with no prior history of thoracic radiation were treated from 10/1/2003 to 10/27/2008 with single-fraction SBRT to thoracic structures. The median dose to the gross tumor volume was 2400 cGy (range 1800–2400 cGy), as was the median dose to the planning target volume (range 1600–2400 cGy). A detailed review of thoracic toxicities was performed to include pneumonitis or Grade 2 or higher esophageal and bronchial toxicity. In addition, we retrospectively contoured the esophagus and bronchus of 48 patients treated in 2004–2005, prior to the establishment of dose constraints to determine the range of doses that these structures received. Results Of the contoured patients, the median dose to the hottest 1 cc (D1cc) of the esophagus was 1250 cGy (range 158–2572 cGy). The median bronchial D1cc was 1101 cGy (range 260–2211 cGy). At a median follow-up of 11.6 months, there were seven Grade 2 or higher esophageal toxicities, including one Grade 3 and one Grade 4 toxicities. There were two bronchial toxicities, one Grade 2 and one Grade 3. There were no cases of pneumonitis. Conclusions High-dose single-fraction SBRT is well tolerated to the thoracic region, with most patients tolerating high doses to central structures without significant toxicity.

A Prospective, Phase II Study Demonstrating the Potential Value and Limitation of Radiosurgery for Spine Metastases

To evaluate toxicity, efficacy, feasibility, and target volume dosimetry of single-fraction stereotactic body radiotherapy or radiosurgery for spine tumors. Twenty-five patients were treated on a prospective phase II protocol of single-fraction stereotactic body radiotherapy or radiosurgery for tumors near the spinal cord (N = 21). Patients received 15 Gy, given a spinal cord limit of 12 Gy to 0.1 mL for patients with no prior spine radiotherapy (N = 9), and 5 Gy to 0.5 mL for patients with prior spine radiotherapy (N = 12). The primary endpoint was toxicity. The secondary endpoint was efficacy measured with a pain scale, 2 neurologic function scales, and magnetic resonance scans. Minor endpoints were feasibility and dose coverage. Acute toxicity was grade 1 to 2 dysphagia or nausea. There were no late toxicities. Three patients experienced radiographic evidence of vertebral body compression in field; 2 were asymptomatic and 1 was managed with vertebroplasty. One patient progressed at the radiosurgery site (local control, 95%); 43% experienced pain relief. Most patients died or developed progressive systemic disease soon after radiosurgery. One-year progression-free survival was 5% with 60% of patients dead by 1 year. Patients with the site of radiosurgery as their only site of disease also did poorly: 2-year progression-free survival ≈ 10% with half dead of cancer within 2 years. There were no problems planning and delivering spine radiosurgery with a 60-minute treatment slot. In patients with and without prior radiotherapy, we achieved our target-coverage goal in 91% and 95%, respectively. Radiosurgery is an excellent option for patients with symptomatic spine metastases in previously irradiated areas. In patients without previous irradiation, the biology of metastatic cancer limits spine radiosurgery's ability to improve outcome.

Phase II Trial of Single Fraction Stereotactic Body Radiotherapy Delivered by Trilogy Linear Accelerator for the Treatment of Locally Advanced Adenocarcinoma of the Pancreas

Phase II Trial of Single Fraction Stereotactic Body Radiotherapy Delivered by Trilogy Linear Accelerator for the Treatment of Locally Advanced Adenocarcinoma of the Pancreas

Comparison of Kilovoltage Cone-Beam Computed Tomography With Megavoltage Projection Pairs for Paraspinal Radiosurgery Patient Alignment and Position Verification

Implanted gold markers and megavoltage (MV) portal imaging are commonly used for setup verification of paraspinal tumors treated with high-dose, single-fraction radiotherapy. We investigated whether the use of kilovoltage cone-beam computed tomography (CBCT) imaging eliminates the need for marker implantation. Patients with paraspinal disease who were eligible for single-fraction stereotactic body radiotherapy were accrued to an institutional review board-approved protocol. Each of 16 patients underwent implantation of fiducial markers near the target. The markers were visible on the MV images. Three MV image pairs were acquired for each patient (initial, verification, and final) and were registered to the reference images. Every MV pair was complemented by a CBCT scan. CBCT image registration was performed automatically by maximizing the mutual information using a region of interest that excluded the markers. The corrections, as determined from the MV images, were compared with these from CBCT and were used for actual patient setup. The mean and standard deviation of the absolute values of the differences between the CBCT and MV corrections were 1.0 +/- 0.7, 1.0 +/- 0.6, and 1.0 +/- 0.8 mm for the left-right, anteroposterior, and superoinferior directions, respectively. The absolute differences between the corresponding pre- and post-treatment kilovoltage CBCT image registration were 0.6 +/- 0.5, 0.6 +/- 0.5, and 1.0 +/- 0.8 mm. The setup corrections found using CBCT without the use of implanted markers were consistent with the marker registration on MV projections. CBCT has additional advantages, including better positioning precision and robust automatic three-dimensional registration, as well as eliminating the need for invasive marker implantation. We have adopted CBCT for the setup of all single-fraction paraspinal patients. Our data have also demonstrated that target displacements during treatment are insignificant.

Gemcitabine Chemotherapy and Single-Fraction Stereotactic Body Radiotherapy for Locally Advanced Pancreatic Cancer

Fractionated radiotherapy and chemotherapy for locally advanced pancreatic cancer achieves only modest local control. This prospective trial evaluated the efficacy of a single fraction of 25 Gy stereotactic body radiotherapy (SBRT) delivered between Cycle 1 and 2 of gemcitabine chemotherapy. A total of 16 patients with locally advanced, nonmetastatic, pancreatic adenocarcinoma received gemcitabine with SBRT delivered 2 weeks after completion of the first cycle. Gemcitabine was resumed 2 weeks after SBRT and was continued until progression or dose-limiting toxicity. The gross tumor volume, with a 2-3-mm margin, was treated in a single 25-Gy fraction by Cyberknife. Patients were evaluated at 4-6 weeks, 10-12 weeks, and every 3 months after SBRT. All 16 patients completed SBRT. A median of four cycles (range one to nine) of chemotherapy was delivered. Three patients (19%) developed local disease progression at 14, 16, and 21 months after SBRT. The median survival was 11.4 months, with 50% of patients alive at 1 year. Patients with normal carbohydrate antigen (CA)19-9 levels either at diagnosis or after Cyberknife SBRT had longer survival (p <0.01). Acute gastrointestinal toxicity was mild, with 2 cases of Grade 2 (13%) and 1 of Grade 3 (6%) toxicity. Late gastrointestinal toxicity was more common, with five ulcers (Grade 2), one duodenal stenosis (Grade 3), and one duodenal perforation (Grade 4). A trend toward increased duodenal volumes radiated was observed in those experiencing late effects (p = 0.13). SBRT with gemcitabine resulted in comparable survival to conventional chemoradiotherapy and good local control. However, the rate of duodenal ulcer development was significant.

Phase II Trial of Gemcitabine and Single Fraction Stereotactic Body Radiotherapy (Trilogy) for the Treatment of Locally Advanced, Unresectable Adenocarcinoma of the Pancreas

Phase II Trial of Gemcitabine and Single Fraction Stereotactic Body Radiotherapy (Trilogy) for the Treatment of Locally Advanced, Unresectable Adenocarcinoma of the Pancreas

Using Pre-radiation PET Parameters to Predict Survival in Adenocarcinoma of the Pancreas Treated With Gemcitabine and Single Fraction Stereotactic Body Radiation Therapy

Although positron emission tomography (PET) scanning has been influential in radiation treatment planning and target delineation, tumor metabolic activity has not been studied as a prognostic factor in predicting individual patient outcomes in pancreatic cancer. In a cohort of 35 patients treated with stereotactic body radiation therapy (SBRT) we analyzed whether pretreatment PET scan parameters could predict for patient survival. This study consists of 35 patients with pancreatic cancer (29 locally advanced and 6 metastatic disease) who had a pre-treatment PET scan and at least 4 months of follow-up. All PET scans were carried out on our GE Discovery-ST CT-PET scanner. PET images were imported into RT_Image (an application developed in our laboratory) for analysis. Pancreatic tumor volume, Maximum SUV, Mean SUV, Minimum SUV and integrated SUV over the tumor volume were calculated for each patient. Survival times from date of pathologic diagnosis were available for all patients. Stereotactic radiation doses of 25 Gy in a single fraction were administered. Among the various PET parameters, maximum SUV (SUVmax) demonstrated the greatest correlation with patient survival. Patients were sorted into two groups based on their SUVmax values. The Hi-SUV group consisted of patients with SUVmax values above the median and the Low-SUV group consisted of patients with SUVmax values below the median. Mean survival from diagnosis was 221 days (stdev 112) in the Hi-SUV group and 469 days (stdev 267) in the Low-SUV group (p value of 0.12 by t-test). Kaplan-Meier survival curves for all patients (Figure 1-Left) and locally advanced patients only (Figure 1-Right) are below. Neither reached significance by log-rank testing (p = 0.63 and 0.20 respectively). Our preliminary data demonstrates a trend between greater maximum SUV on pre-treatment PET scan and a reduction in overall survival. A larger sample size and longer follow-up will be available at time of presentation.

Tissue Effects after Stereotactic Body Radiotherapy using Cyberknife for Patients with Abdominal Malignancies

Aims To report the tissue effects of treatment with single fraction stereotactic body radiotherapy (SBRT) using Cyberknife on malignant tumours of the abdomen and adjacent normal organs. Materials and methods The data from four autopsies with unresectable pancreatic carcinoma and one lymph node excision from a case of recurrent neuroblastoma were reviewed for radiation-related tissue effects within the primary cancer and the normal organs within the radiation field. Results Cases of unresectable pancreatic carcinoma consistently showed radiation-induced changes in both the primary tumour and the adjacent, non-malignant colorectal tissue. An additional case of lymph nodes exposed to stereotactic radiation showed typical radiation-related changes, including lymphocyte depletion and capsular fibrosis. Conclusions A myriad of radiation-related tissue effects are seen after SBRT with Cyberknife. The changes parallel those reported after conventionally fractionated radiotherapy and suggest that the pathophysiological mechanisms of radiation-induced normal tissue damage are similar for biologically equivalent single and fractionated doses of radiotherapy.