Clinical Presentation and Management of SMART Syndrome

Management of Neurologic Complications in Patients with Brain and Spine Tumors

Patients with brain and spine tumors represent a distinct population with unique needs. We provide a practical review of neurologic care in this group with an emphasis on familiarizing the general neurologist to the nuances of neuro-oncologic supportive care. We review the management of cerebral edema, steroid dosing, and pertinent side effects. We discuss seizure management, including choice of anticonvulsants, putative antitumor effects, and important seizure mimics like drop attacks. We review the presentation and symptomatology of stroke-like migraine attack after radiation therapy (SMART syndrome). We describe the signs and symptoms that should prompt concern for metastatic spinal cord compression, as well as both acute and definitive treatment options. Finally, we discuss the underappreciated incidence of venous thromboembolic events, particularly in patients with gliomas, and review the data on management.

Neurologic Complications of Conventional Chemotherapy and Radiation Therapy

OBJECTIVE

Neurologic complications are among the most common and feared outcomes of cancer treatments. This review discusses the signs and symptoms, mechanisms, and management of the most common peripheral and central neurologic complications of chemotherapy, radiation therapy, and antiangiogenic therapy during cancer treatment and in survivors.

LATEST DEVELOPMENTS

The landscape of cancer treatments is evolving to include more targeted and biologic therapies, in addition to more traditional cytotoxic therapies and radiation therapy. With increasingly complex regimens and longer survival for patients with cancer, the early recognition and management of neurologic complications is key to improving the morbidity and mortality of patients living with cancer.

ESSENTIAL POINTS

Neurologists should be familiar with acute central and peripheral toxicities that can occur during cancer treatment and delayed toxicities that can occur years after exposure. Neurologists should be familiar with the clinical and radiologic presentations of these complications and strategies for management.

Mitigating Radiotoxicity in the Central Nervous System: Role of Proton Therapy

OPINION STATEMENT

Central nervous system (CNS) radiotoxicity remains a challenge in neuro-oncology. Dose distribution advantages of protons over photons have prompted increased use of brain-directed proton therapy. While well-recognized among pediatric populations, the benefit of proton therapy among adults with CNS malignancies remains controversial. We herein discuss the role of protons in mitigating late CNS radiotoxicities in adult patients. Despite limited clinical trials, evidence suggests toxicity profile advantages of protons over conventional radiotherapy, including retention of neurocognitive function and brain volume. Modelling studies predict superior dose conformality of protons versus state-of-the-art photon techniques reduces late radiogenic vasculopathies, endocrinopathies, and malignancies. Conversely, potentially higher brain tissue necrosis rates following proton therapy highlight a need to resolve uncertainties surrounding the impact of variable biological effectiveness of protons on dose distribution. Clinical trials comparing best photon and particle-based therapy are underway to establish whether protons substantially improve long-term treatment-related outcomes in adults with CNS malignancies.

Comprehensive Update and Review of Clinical and Imaging Features of SMART Syndrome

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a delayed complication of cranial irradiation, with subacute onset of stroke-like symptoms including seizures, visual disturbance, speech impairment, unilateral hemianopsia, facial droop, and aphasia, often associated with migraine-type headache. The diagnostic criteria were initially proposed in 2006. However, the diagnosis of SMART syndrome is challenging because clinical symptoms and imaging features of SMART syndrome are indeterminate and overlap with tumor recurrence and other neurologic diseases, which may result in inappropriate clinical management and unnecessary invasive diagnostic procedures. Recently, various imaging features and treatment recommendations for SMART syndrome have been reported. Radiologists and clinicians should be familiar with updates on clinical and imaging features of this delayed radiation complication because recognition of this entity can facilitate proper clinical work-up and management. This review provides current updates and a comprehensive overview of the clinical and imaging features of SMART syndrome.

Isocitrate dehydrogenase (IDH) mutant gliomas: A Society for Neuro-Oncology (SNO) consensus review on diagnosis, management, and future directions

Isocitrate dehydrogenase (IDH) mutant gliomas are the most common adult, malignant primary brain tumors diagnosed in patients younger than 50, constituting an important cause of morbidity and mortality. In recent years, there has been significant progress in understanding the molecular pathogenesis and biology of these tumors, sparking multiple efforts to improve their diagnosis and treatment. In this consensus review from the Society for Neuro-Oncology (SNO), the current diagnosis and management of IDH-mutant gliomas will be discussed. In addition, novel therapies, such as targeted molecular therapies and immunotherapies, will be reviewed. Current challenges and future directions for research will be discussed.

Stroke-Like Migraine Attacks After Radiation Therapy Syndrome and Radiation Necrosis After Cerebral Proton Beam Radiation: A Case Report of Dual Radiotherapy Complications

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a rare, delayed complication of cranial radiation therapy that consists of migraine-like headaches and focal neurologic deficits such as visual loss, aphasia, hemiparesis, hemisensory loss, and unconsciousness. SMART syndrome may be mistaken for tumor recurrence, radiation necrosis, and stroke. Timely recognition of SMART syndrome prevents unnecessary brain biopsies and enables appropriate anticipatory guidance. We present a 38 year-old right handed male with new headaches, vertigo, visual symptoms, and left-sided paresthesias. Neuroimaging revealed a heterogeneously enhancing mass with invasion into the transverse sinus, diagnosed as an epithelioid hemangioendothelioma by surgical pathology. After resection, the patient underwent proton beam radiation for maximal tissue-sparing. Six months later, he developed radiation necrosis. After another year, he developed recurrent headaches with transient language difficulties and blurry vision during each headache. Neuroimaging was consistent with SMART syndrome, and the patient was started on valproate. Verapamil was added after a second attack. The patient’s headaches improved, but he remains dyslexic. Subsequent imaging shows resolution of gyriform contrast enhancement and continued left temporo-occipital T2/FLAIR hyperintensity. We present a case of early SMART syndrome following proton beam radiotherapy, as well as the dual occurrence of radiation necrosis and SMART syndrome in this individual. Radiation necrosis and SMART syndrome are known complications of radiotherapy, with the latter less well-described. We discuss a possible shared pathophysiology involving endothelial cell dysfunction and impaired cerebrovascular autoregulation, and we question whether proton RT increases risk of early SMART syndrome development.

Central Nervous System Complications Among Oncology Patients

Cancer treatment related injury to the central nervous system (CNS) is well-recognized in the setting of brain-directed radiation therapies and conventional and novel systemic anticancer therapies. Late-delayed treatment-induced CNS complications frequently result in permanent neurologic disability. Therapeutic options are supportive with limited clinical benefit, whereby alteration or discontinuation of the overall antineoplastic treatment plan is frequently necessary to prevent further neurologic injury. Better identification of patients at high risk for developing late CNS toxicities, neuroprotective strategies with modification of existing antineoplastic treatment regimens, and research efforts directed at earlier recognition and improved treatment of central neurologic complications are paramount.