Impact of Resecting Radiation Necrosis and Pseudoprogression on Survival of Patients with Glioblastoma.

INTRODUCTION: Radiation necrosis (RN) and pseudoprogression are known as postradiation treatment effects and may simulate tumor progression. The disease course of glioblastoma patients who had developed RN and the impact of resecting RN on survival have not been evaluated. This study examines the clinical course of patients considered candidates for repeat surgery for a recurring brain mass proven to be RN and compared these with patients who had true tumor recurrence at surgery. METHODS: Of 159 patients with glioblastoma who were reoperated on because of a presumed recurrent tumor requiring repeat surgery, 18 had RN as the major component of the resected mass. The characteristics and outcome of these 18 patients were retrospectively analyzed and compared with patients in whom active and bulky tumor was found during surgery. RESULTS: Radiation necrosis occurred significantly earlier than true tumor recurrence. Patients with RN harbored larger lesions and were significantly more symptomatic before the second surgery. Most patients with RN who underwent GTR of the lesion in the second operation experienced faster resolution of the surrounding edema compared with patients who underwent STR or biopsy only. There was no significant difference in survival between the 2 groups. CONCLUSIONS: These data provide an opportunity to examine the clinical course of a selected group of patients with histologically verified RN. Although RN is associated with more severe neurologic symptoms that improve after surgery, its occurrence or surgical removal carries no survival advantage compared with patients who undergo a repeat operation for true tumor recurrence.

Limited advantages of intensity-modulated radiotherapy over 3D conformal radiation therapy in the adjuvant management of gastric cancer.

PURPOSE: Although chemoradiotherapy was considered the standard adjuvant treatment for gastric cancer, a recent Phase III trial (Medical Research Council Adjuvant Gastric Infusional Chemotherapy [MAGIC]) did not include radiotherapy in the randomization scheme because it was considered expendable. Given radiotherapy's potential, efforts needed to be made to optimize its use for treating gastric cancer. We assessed whether intensity-modulated radiotherapy (IMRT) could improve upon our published results in patients treated with three-dimensional (3D) conformal therapy. METHODS AND MATERIALS: Fourteen patients with adenocarcinoma of the stomach were treated with adjuvant chemoradiotherapy using a noncoplanar four-field arrangement. Subsequently, a nine-field IMRT plan was designed using a CMS Xio IMRT version 4.3.3 module. Two IMRT beam arrangements were evaluated: beam arrangement 1 consisted of gantry angles of 0 degrees , 53 degrees , 107 degrees , 158 degrees , 204 degrees , 255 degrees , and 306 degrees . Beam arrangement 2 consisted of gantry angles of 30 degrees , 90 degrees , 315 degrees , and 345 degrees ; a gantry angle of 320 degrees /couch, 30 degrees ; and a gantry angle of 35 degrees /couch, 312 degrees . Both the target volume coverage and the dose deposition in adjacent critical organs were assessed in the plans. Dose-volume histograms were generated for the clinical target volume, kidneys, spine, and liver. RESULTS: Comparison of the clinical target volumes revealed satisfactory coverage by the 95% isodose envelope using either IMRT or 3D conformal therapy. However, IMRT was only marginally better than 3D conformal therapy at protecting the spine and kidneys from radiation. CONCLUSIONS: IMRT confers only a marginal benefit in the adjuvant treatment of gastric cancer and should be used only in the small subset of patients with risk factors for kidney disease or those with a preexisting nephropathy.