Article
Clinicoradiographic key features of biopsy-proven treatment-induced necrosis in patients with malignant glioma
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Published: | June 18, 2018 |
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Objective: Treatment-induced brain tissue necrosis (TN) in malignant glioma remains a challenging and poorly characterized condition. Because TN radiographically mimics recurrent disease, many patients undergo tissue biopsy to guide management, resulting in many unnecessary surgical interventions. We here characterize the clinical and radiographic features of biopsy-proven TN with the aim to establish pre-selection criteria for patients requiring biopsy.
Methods: Clinical, radiographic, and histopathological data of patients with malignant glioma and biopsy-proven TN (defined as appearance >6 months post radiotherapy (RT) initiation) were retrospectively analyzed. The spatiotemporal radiographic pattern of each imaging event/lesion (ROI) diagnosed as TN was evaluated using data from standard T1+C weighted MRI sequences. Each ROI was spatially correlated to the patient's RT dose curves. Additional non-biopsied ROIs in the same patient with clinical-radiographic TN diagnosis were included in the analysis.
Results: 25 patients with biopsy-proven TN and predominantly WHO Grade III (40%) and IV (40%) gliomas (65% IDH1-mutated, n=11/17) developed a total of 71 individual radiographic ROIs (n=33 biopsy-proven, n=38 radiographically diagnosed). Median age at diagnosis was 49 years (yrs) (range: 21–69 yrs). All patients underwent RT, 72% had concurrent chemoradiation, and all but three received adjuvant chemotherapy. Mean OS from initial diagnosis was 7.8 yrs and >10 yrs for 40% of the patients. Median onset of TN post-RT completion was 11 months (mo) (range: 5 mo–11.9 yrs) and associated with new symptoms in most patients, fully attributable to TN in 59% of cases. On average, patients developed 3 nodular ROIs (range: 1–9) of 1.1 cm2 median size (range: 0.2–32.4 cm2) located at 20.5 mm median distance (range: 0–78 mm) from the resection cavity. Almost half of all ROIs occurred in periventricular regions; 80% of patients developed at least one ROI in this location. 97.8% (44/45) of lesions were located within the main radiation field. Approximately 1/3 of ROIs were traced longitudinally until full resolution, persisting for a median interval of 12.5 months (range: 2–37 mo).
Conclusion: TN usually occurred within a year post-chemoradiation as multiple small enhancing nodules with periventricular preference, symptomatic sequelae, and substantial spatio-temporal heterogeneity. TN may radiographically resolve within a year and is associated with longer survival in patients with high-grade glioma.