Showing papers by "Barbara Fisher published in 2005"

Radiotherapy plus Concomitant and Adjuvant Temozolomide for Glioblastoma

Abstract: methods Patients with newly diagnosed, histologically confirmed glioblastoma were randomly assigned to receive radiotherapy alone (fractionated focal irradiation in daily fractions of 2 Gy given 5 days per week for 6 weeks, for a total of 60 Gy) or radiotherapy plus continuous daily temozolomide (75 mg per square meter of body-surface area per day, 7 days per week from the first to the last day of radiotherapy), followed by six cycles of adjuvant temozolomide (150 to 200 mg per square meter for 5 days during each 28-day cycle). The primary end point was overall survival. results A total of 573 patients from 85 centers underwent randomization. The median age was 56 years, and 84 percent of patients had undergone debulking surgery. At a median follow-up of 28 months, the median survival was 14.6 months with radiotherapy plus temozolomide and 12.1 months with radiotherapy alone. The unadjusted hazard ratio for death in the radiotherapy-plus-temozolomide group was 0.63 (95 percent confidence interval, 0.52 to 0.75; P<0.001 by the log-rank test). The two-year survival rate was 26.5 percent with radiotherapy plus temozolomide and 10.4 percent with radiotherapy alone. Concomitant treatment with radiotherapy plus temozolomide resulted in grade 3 or 4 hematologic toxic effects in 7 percent of patients.

Secondary analysis of Radiation Therapy Oncology Group study (RTOG) 9310: an intergroup phase II combined modality treatment of primary central nervous system lymphoma

Abstract: Purpose: To determine whether a lower dose of hyperfractionated whole brain radiation reduces central nervous system morbidity without compromising survival for primary CNS lymphoma (PCNSL) patients receiving combined modality treatment. Materials and Methods: One hundred and two patients received a course of pre-radiation chemotherapy, followed by whole brain radiation, followed by cytosine-arabinoside. Initial radiation dose was 45 Gy/25 fractions (RT) then the study was amended to reduce this dose for complete responders to induction chemotherapy to 36 Gy/30 fractions/3 weeks (HFX). Eighty-two patients received radiotherapy and were evaluable for toxicity analysis (66 RT patients and 16 HFX patients). MMSE scores and survival for the 40 patients who received radiotherapy after complete response to chemotherapy (27 RT and 13 HFX) were compared. There were no notable differences in pre-treatment patient characteristics between the RT and HFX groups. Results: Neurotoxicity: By 4 years, there were 8/82 (10%) grade 5 neurotoxicities which included 2/16 (13%) grade 5 encephalopathies and 0/27 in the RT group of complete responders to chemotherapy. Survival: There was no statistically significant difference in overall or progression-free survival (PFS) between the chemotherapy-complete responders who received RT and HFX. Cognitive function testing: MMSE scores improved at 8 months across both treatment groups. Analysis of the area under the MMSE curve at 8 months showed no statistically significant difference between RT and HFX groups (P=0.81). Leukoencephalopathy occurred later in the HFX group than in the RT patients. Conclusion: Although the HFX schedule represented a 25% reduction in biologically effective tumor dose in comparison, PFS and overall survival were not significantly affected. The HFX regimen delayed but did not eliminate severe neurotoxicity from chemoradiation in PCNSL patients.

Helical tomotherapy for craniospinal radiation.

Abstract: Helical tomotherapy (HT) plans for craniospinal radiation were generated for the case of a 4-year-old boy with disseminated ependymoma The HT plans demonstrated excellent target coverage, homogeneity and organ sparing compared with a conventional linear accelerator based craniospinal radiation plan On the basis of this case study, further evaluation of HT for craniospinal radiotherapy seems justified

Case report Helical tomotherapy for craniospinal radiation

Abstract: Helical tomotherapy (HT) plans for craniospinal radiation were generated for the case of a 4-year-old boy with disseminated ependymoma. The HT plans demonstrated excellent target coverage, homogeneity and organ sparing compared with a conventional linear accelerator based craniospinal radiation plan. On the basis of this case study, further evaluation of HT for craniospinal radiotherapy seems justified. Patients with brain tumours at risk for dissemination through the cerebrospinal fluid often require craniospinal axis irradiation. Comprehensive irradiation of the cranio- spinal space is technically demanding (1-5). Craniospinal radiation typically utilizes prone positioning of the patient combined with careful junctioning between opposed lateral cranial fields and a posterior spine field. In larger patients, an additional junction between upper and lower spine fields may be required (4). Periodic junction shifts are introduced throughout the treatments to address the potential risk of underdose or overdose at the field junctions. Many of the patients requiring craniospinal radiotherapy are paediatric patients who may have difficulty cooperating with prone positioning for treatment and also may require daily anaesthesia for treatment. In these cases, supine positioning may be preferable depend- ing on the institution preference. With either supine or prone positioning, the challenge of setting and verifying multiple field junctions and the maintenance of a homogeneous dose over a long treatment volume remains (2, 3). Helical tomotherapy (HT) is a novel approach to the delivery of radiation for cancer treatment (6, 7). It relies on a 6 MV linear accelerator mounted on a ring gantry that rotates around the patient as they advance slowly through the ring. During treatment delivery, the radiation fan beam is defined using a 64-leaf collimator. Each leaf projects a shadow of 0.625 mm width at the isocentre 85 cm away from the target and the fan beam width is adjustable from 0.5 cm to 5 cm. The alteration of leaf positions as a function of the gantry position while the patient advances slowly through the gantry allows great flexibility in sculpting a sophisticated target dose distribu- tion while sparing critical normal structures. In addition, the smooth, helical delivery of the intensity-modulated fan beam allows the treatment of extended volumes in the cephalo-caudad direction in either the prone or supine position without the need for junctioning. We sought to model the potential advantages of HT delivery for craniospinal radiation for the case of a paediatric patient with disseminated ependymoma. Materials and methods Patient presentation and treatment The patient was initially diagnosed with a well- differentiated ependymoma of the posterior fossa at age 18 months. The tumour recurred despite multiple surgical resections and once the child reached 4 years of age, a decision was made to treat the child with craniospinal irradiation under general anaesthesia. At the time of treatment, the child had gross tumour remaining in the 3rd and 4th ventricular regions in close proximity to brainstem and optic apparatus as well as a gross tumour deposit in the spine at L4. Given the potential risk of neurocognitive side effects in a 4-year-old child and the proximity of the gross tumour to brainstem, optic apparatus and spinal cord it was decided to limit the total gross tumour volume dose to 45 Gy with a craniospinal dose of 36 Gy. For radiation treatment planning CT images from the vertex of the skull to the ischial tuborosities was acquired with uniform slice thickness and spacing of 3 mm. For clinical treatment the patient was planned and treated with a linear accelerator (LINAC) based technique. The LINAC treatment utilized a half-beam blocked technique to match the cranial and upper spinal fields. A second, lower spinal field was placed using a fixed longitudinal displacement from the superior junction using the exact bed positioning system. Field width for the posterior spine field was 6 cm with the lateral field borders extending to the edge of the transverse processes of the vertebrae. Three junction shifts of 0.5 cm were introduced using asymmetric jaws to maintain the matchline. For the final phase of treatment, reduced size, opposed lateral fields were used to boost the gross disease within the cranium while a single posterior spine field was used to boost the cauda equina disease. For this case study the archived CT planning dataset used for the LINAC treatment was re-planned at a later date using the HT system to explore potential benefits and limitations of this form of intensity-modulated radiation delivery for craniospinal treatment.