Epilepsy related to radiotherapy in patients with nasopharyngeal carcinoma

Neurotoxicity-sparing radiotherapy for brain metastases in breast cancer: a narrative review

Breast cancer brain metastasis (BCBM) has a devastating impact on patient survival, cognitive function and quality of life. Radiotherapy remains the standard management of BM but may result in considerable neurotoxicity. Herein, we describe the current knowledge on methods for reducing radiation-induced cognitive dysfunction in patients with BCBM. A better understanding of the biology and molecular underpinnings of BCBM, as well as more sophisticated prognostic models and individualized treatment approaches, have appeared to enable more effective neuroprotection. The therapeutic armamentarium has expanded from surgery and whole-brain radiotherapy to stereotactic radiosurgery, targeted therapies and immunotherapies, used sequentially or in combination. Advances in neuroimaging have allowed more accurate screening for intracranial metastases, precise targeting of intracranial lesions and the differentiation of the effects of treatment from disease progression. The availability of numerous treatment options for patients with BCBM and multidisciplinary approaches have led to personalized treatment and improved therapeutic outcomes. Ongoing studies may define the optimal sequencing of available and emerging treatment options for patients with BCBM.

A detailed dosimetric comparative study of IMRT and VMAT in normal brain tissues for nasopharyngeal carcinoma patients treated with radiotherapy

Background

Radiotherapy (RT) is the primary treatment for nasopharyngeal carcinoma (NPC). However, it can cause implicit RT-induced injury by irradiating normal brain tissue. To date, there have been no detailed reports on the radiated exact location in the brain, the corresponding radiation dose, and their relationship.

Methods

We analyzed 803 Chinese NPC patients treated with RT and used a CT brain template in a Montreal Neurological Institute (MNI) space to compare the group differences in RT dose distribution for different RT technologies (IMRT or VMAT).

Results

Brain regions that received high doses (>50 Gy) of radiation were mainly located in parts of the temporal and limbic lobes, where radioactive damage often occurs. Brain regions that accepted higher doses with IMRT were mainly located near the anterior region of the nasopharyngeal tumor, while brain regions that accepted higher doses with VMAT were mainly located near the posterior region of the tumor. No significant difference was detected between IMRT and VMAT for T1 stage patients. For T2 stage patients, differences were widely distributed, with VMAT showing a significant dose advantage in protecting the normal brain tissue. For T3 stage patients, VMAT showed an advantage in the superior temporal gyrus and limbic lobe, while IMRT showed an advantage in the posterior cerebellum. For T4 stage patients, VMAT showed a disadvantage in protecting the normal brain tissue. These results indicate that IMRT and VMAT have their own advantages in sparing different organs at risk (OARs) in the brain for different T stages of NPC patients treated with RT.

Conclusion

Our approach for analyzing dosimetric characteristics in a standard MNI space for Chinese NPC patients provides greater convenience in toxicity and dosimetry analysis with superior localization accuracy. Using this method, we found interesting differences from previous reports: VMAT showed a disadvantage in protecting the normal brain tissue for T4 stage NPC patients.

Radiation-induced brain injury: current concepts and therapeutic strategies targeting neuroinflammation

Continued improvements in cancer therapies have increased the number of long-term cancer survivors. Radiation therapy remains one of the primary treatment modalities with about 60% of newly diagnosed cancer patients receiving radiation during the course of their disease. While radiation therapy has dramatically improved patient survival in a number of cancer types, the late effects remain a significant factor affecting the quality of life particularly in pediatric patients. Radiation-induced brain injury can result in cognitive dysfunction, including hippocampal-related learning and memory dysfunction that can escalate to dementia. In this article, we review the current understanding of the mechanisms behind radiation-induced brain injury focusing on the role of neuroinflammation and reduced hippocampal neurogenesis. Approaches to prevent or ameliorate treatment-induced side effects are also discussed along with remaining challenges in the field.

An overview of anti-epileptic therapy management of patients with malignant tumors of the brain undergoing radiation therapy

As our surgical, radiation, chemotherapeutic and supportive therapies for brain malignancies improve, and overall survival is prolonged, appropriate symptom management in this patient population becomes increasingly important. This review summarizes the published literature and current practice patterns regarding prophylactic and perioperative anti-epileptic drug use. As a wide range of anti-epileptic drugs is now available to providers, evidence guiding appropriate anticonvulsant choice is reviewed. A particular focus of this article is radiation therapy for brain malignancies. Toxicities and seizure risk associated with cranial irradiation will be discussed. Epilepsy management in patients undergoing radiation for gliomas, glioblastoma multiforme, and brain metastases will be addressed. An emerging but inconsistent body of evidence, reviewed here, indicates that anti-epileptic medications may increase radiosensitivity, and therefore improve clinical outcomes, specifically in glioblastoma multiforme patients.

Cortical Surface Area Rather Than Cortical Thickness Potentially Differentiates Radiation Encephalopathy at Early Stage in Patients With Nasopharyngeal Carcinoma

Radiation encephalopathy (RE) is one of the most severe complications in nasopharyngeal carcinoma (NPC) patients after radiotherapy (RT). However, the morphological alteration of early RE is insufficiently investigated. We aimed to investigate the cortical thickness and surface area alterations in NPC patients with or without RE in the follow-up. A total of 168 NPC patients each underwent a single scan and analysis at various times either Pre-RT (n = 56) or Post-RT (n = 112). We further divided the Post-RT NPC patients into three groups based on the time of the analysis following RT (Post-RT_{within 6 months} and Post-RT_{7-12 months}) or whether RE signs were detected in the analysis (Post-RT_{RE proved in follow-up}). We confined the vertex-wise analyses of the cortical thickness and surface area to the bilateral temporal lobes. Interestingly, we revealed a gradual increase in the cortical surface area of the temporal lobe with increasing time after RT within the Post-RT_{RE proved in follow-up} group, consistent with the between-group findings, which showed a significant increase in cortical surface area in the Post-RT_{RE proved in follow-up} group relative to the Pre-RT group and the Post-RT_{within 6 months} group. By contrast, such a trend was not observed in the cortical thickness findings. We concluded that the cortical surface area, rather than cortical thickness, may serve as a potential biomarker for early diagnosis of RE.

Bilateral thalamic and mesencephalic infarctions with hypopituitarism as long-term complications postradiotherapy: A case report

BACKGROUND

Radiation is widely used as the first-line treatment for nasopharyngeal carcinoma (NPC) and improves survival. Nevertheless, radiation also places the patients at risk of radiation-induced adverse effects, such as transient ischemic attack, ischemic stroke, hypopituitarism, and cranial nerve and temporal lobe dysfunction.

CASE REPORT

A 54-year-old woman who had undergone radiation treatment for NPC 14 years earlier and had no cerebrovascular risk factors, visited our department 4 days after sudden onset of consciousness disturbance. Brain magnetic resonance imaging (MRI) revealed bilateral thalamic and left mesencephalic infarctions with empty sella. Meanwhile, MR angiography showed narrowing in the bilateral posterior cerebral artery. Furthermore, laboratory tests showed low total triiodothyronine (T3), thyroxine (T4), free T3, free T4, luteinizing hormone, estradiol, follicle-stimulating hormone, and serum natrium and normal thyroid-stimulating hormone, which indicated radiation-related hypopituitarism. Serologically, she had low hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, ferritin, and serum iron levels and elevated transferrin, manifesting microcytic anemia. The treatment, including aspirin, atorvastatin, levothyroxine, prednisone, saline infusion, and chalybeate, promoted the patient's recovery.

CONCLUSION

To our knowledge, this is the first report of bilateral thalamic and mesencephalic infarction together with hypopituitarism following radiotherapy for NPC.

Differences in Clinicopathological Characteristics and Prognosis Between Primary and Postirradiation Tongue Squamous Cell Carcinoma

PURPOSE

Many cases of postirradiation oral carcinoma have been reported, but its prognosis and optimal treatment modalities are not clear. Thus, the clinicopathologic characteristics and prognosis between postirradiation tongue squamous cell carcinoma (PTSCC) and primary tongue squamous cell carcinoma (TSCC) were compared.

PATIENTS AND METHODS

A retrospective cohort study was conducted to assess patients with PTSCC or TSCC. The primary predictor variable was tumor type. The primary outcome variable was prognosis, and the additional outcome variables were clinicopathologic characteristics. Survival analysis was performed, and Kaplan-Meier analysis was conducted to compare the effects of clinicopathologic factors on survival using SPSS 18.0. Moreover, the Cox model was applied in multivariate analysis.

RESULTS

The sample was composed of 449 patients with PTSCC (n = 68; 47 men and 21 women; age range, 31 to 72 yr) and TSCC (n = 381; 247 men and 134 women; age range, 20 to 86 yr). Patients with PTSCC were found to have a substantially poorer prognosis and several specific clinicopathologic characteristics compared with patients with TSCC.

CONCLUSION

Patients with PTSCC had several unique biological tumor characteristics and a poorer prognosis than patients with TSCC. Thus, different surgical strategies should be used to treat patients with PTSCC.

Clinical and prognostic analysis of second primary squamous cell carcinoma of the tongue after radiotherapy for nasopharyngeal carcinoma

We have investigated the clinical characteristics and prognostic factors of squamous cell carcinoma (SCC) of the tongue after definitive radiotherapy for nasopharyngeal carcinoma, and evaluated the effect of common therapeutic regimens for these patients. We retrospectively reviewed follow-up data for patients whose nasopharyngeal carcinoma had been treated by radiotherapy, and selected the 68 who had then developed SCC of the tongue, in the border of the tongue in half, and in the dorsum in 25 (37%). Eight of the 68 patients had clinical lymph node metastasis (12%), and 45 presented with stage I-II disease at the time of the diagnosis of the SCC (66%). Resection or radiotherapy alone was an effective treatment for patients with stage I-II SCC of the tongue, but patients with stage III-IV disease had a poor prognosis, despite being given multidisciplinary treatment. Multivariate analysis showed that the risk factors that independently influenced the survival of these patients were use of alcohol, recurrence of their nasopharyngeal carcinoma, the latency period, and the clinical TNM stage. Tongue SCC after radiotherapy was generally at an early stage and commonly occurred on the border or the dorsum of the tongue, with few lymph node metastases. Resection or radiotherapy is an effective treatment, and the risk factors that independently influenced the survival of patients indicate that improving the technique of radiotherapy and close follow-up after nasopharyngeal cancer are vitally important.