Friday, October 7, 2011

Vestibular Schwannoma treated with FSRT

In the Red Journal this week.

Johns Hopkins reports a sizeable series of vestibular schwannomas treated with FSRT. Interestingly, the failure rate (as defined by the need for salvage series) was quite low as expected at 3%, however a fairly large portion had some evidence of radiologic progression (30%).

Link and Abstract

Long-Term Outcomes of Vestibular Schwannomas Treated With Fractionated Stereotactic Radiotherapy: An Institutional Experience: Purpose: We assessed clinical outcome and long-term tumor control after fractionated stereotactic radiotherapy (FSRT) for unilateral schwannoma.Methods and Materials: Between 1995 and 2007, 496 patients were treated with fractionated stereotactic radiotherapy at Johns Hopkins Hospital (Baltimore, MD); 385 patients had radiologic follow-up that met the inclusion criteria. The primary endpoint was treatment failure. Secondary endpoints were radiologic progression and clinical outcome. Logistic regression analysis assessed the association of age, race, tumor side, sex, and pretreatment symptoms.Results: In 11 patients (3%) treatment failed, and they required salvage (microsurgical) treatment. Radiologic progression was observed in 116 patients (30.0%), including 35 patients (9%) in whom the treatment volume more than doubled during the follow-up period, although none required surgical resection. Tumors with baseline volumes of less than 1 cm3 were 18.02 times more likely to progress than those with tumor volumes of 1 cm3 or greater (odds ratio, 18.02; 95% confidence interval, 4.25–76.32). Treatment-induced neurologic morbidity included 8 patients (1.6%) with new facial weakness, 12 patients (2.8%) with new trigeminal paresthesias, 4 patients (0.9%) with hydrocephalus (1 communicating and 3 obstructive), and 2 patients (0.5%) with possibly radiation-induced neoplasia.Conclusions: Although the rate of treatment failure is low (3%), careful follow-up shows that radiologic progression occurs frequently. When reporting outcome, the “no salvage surgery needed” and “no additional treatment needed” criteria for treatment success need to be complemented by the radiologic data.

A Simpler RPA for GBM

In the red journal this week:

A simpler RPA limited to GBM is present from the RTOG, demonstrating a much more practical means of prognostic clasification.

Link and Abstract

Validation and Simplification of the Radiation Therapy Oncology Group Recursive Partitioning Analysis Classification for Glioblastoma: Purpose: Previous recursive partitioning analysis (RPA) of patients with malignant glioma (glioblastoma multiforme [GBM] and anaplastic astrocytoma [AA]) produced six prognostic groups (I–VI) classified by six factors. We sought here to determine whether the classification for GBM could be improved by using an updated Radiation Therapy Oncology Group (RTOG) GBM database excluding AA and by considering additional baseline variables.Methods and Materials: The new analysis considered 42 baseline variables and 1,672 GBM patients from the expanded RTOG glioma database. Patients receiving radiation only were excluded such that all patients received radiation+carmustine. “Radiation dose received” was replaced with “radiation dose assigned.” The new RPA models were compared with the original model by applying them to a test dataset comprising 488 patients from six other RTOG trials. Fitness of the original and new models was evaluated using explained variation.Results: The original RPA model explained more variations in survival in the test dataset than did the new models (20% vs. 15%) and was therefore chosen for further analysis. It was reduced by combining Classes V and VI to produce three prognostic classes (Classes III, IV, and V+VI), as Classes V and VI had indistinguishable survival in the test dataset. The simplified model did not further improve performance (explained variation 18% vs. 20%) but is easier to apply because it involves only four variables: age, performance status, extent of resection, and neurologic function. Applying this simplified model to the updated GBM database resulted in three distinct classes with median survival times of 17.1, 11.2, and 7.5 months for Classes III, IV, and V+VI, respectively.Conclusions: The final model, the simplified original RPA model combining Classes V and VI, resulted in three distinct prognostic groups defined by age, performance status, extent of resection, and neurologic function. This classification will be used in future RTOG GBM trials.