The clinicopathological characteristics, MRI features, and radiation dose of radio-induced brain necrosis in nasopharyngeal carcinoma patients

Abstract

Background: Radio-induced brain necrosis is a late-onset radiotherapy complication, especially in nasopharyngeal carcinoma (NPC) patients. We presented the clinicopathological characteristics, dynamic changes of MRI features, and radiation dose in the areas of radio-induced brain necrosis, which will shed light on preventing this severe radiotherapy complication. Methods: We retrospectively collecting and reanalyzing clinical, imaging, radiation plans and pathological data from 48 NPC patients diagnosed with radio-induced brain necrosis and underwent craniotomy. To calculate the radiation dose in the areas of radio-induced brain necrosis, we reviewed the radiation plan of each patient and delineated the volume of the radio-induced brain necrosis. We also mapped the dynamic changes of magnetic resonance imaging (MRI) features and performed CD3, CD31, CD68, CD11b, Ki67, terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL) and HE staining on radio-induced brain necrosis specimens to observe pathological changes. Results: The mean latency period for radio-induced brain necrosis was 9.23 years. According to the radiotherapy plans, the mean radiation dose for NPC was 7041±553 cGy. The mean dose to the radio-induced brain necrosis area was 5684.57±409.99 cGy. The necrotic areas exhibited high-intensity signals on T2-weighted images (WIs) and low-intensity signals on T1WIs over time. HE staining showed that the necrotic areas contained irregular fibers and inflammatory cells. The immunohistochemical results showed CD3(+), CD31(+), CD68(+), CD11b(+), Ki67(+), and TUNEL(+) cells in radio-induced brain necrosis specimens. Conclusions: NPC patients who underwent radiotherapy and survived more than 5 years with hyperintense signals in temporal lobes in the T2WI should be paid close attention to radio-induced brain necrosis. A radiation dose no more than 5684.57±409.99 cGy in temporal lobes of NPC patients is recommended.