Radiation-Induced Optic Neuropathy: Literature Review

Stereotactic radiotherapy for uveal melanoma: A case report

Uveal melanoma (UM) is the most common primary intraocular malignancy worldwide. Surgical intervention and radiation therapy (RT) are the primary treatment options. Given the complexity and cosmetic discomfort associated with eye enucleation, this method is less frequently used. As a result, RT, including photon therapy, proton therapy and brachytherapy, has become the treatment of choice. Traditionally, plaque brachytherapy has been the most commonly used in clinical practice. However, the question of which type of radiation therapy is the most effective, safe, commonly available and cost-effective remains open. The present study provided a follow-up analysis of a patient with UM who was treated using the image-guided volumetric modulated arc therapy (IG-VMAT) technique. A complete response without complications and symptom relief were noted one and a half years after treatment. The present findings suggest that photon external beam radiotherapy using the IG-VMAT technique may offer a viable and safe alternative for the management of UM. This approach potentially sidesteps the complex and morbid aspects of surgical intervention and plaque brachytherapy. Owing to the limited sample size, a more robust understanding of the efficacy and safety of this treatment will require the analysis of additional cases. Further research with a larger cohort is essential to validate these preliminary observations.

Neurologic Complications in Adult Cancer Survivorship

Over the past decade, the improvement in cancer diagnostics and therapeutics has extended the overall survival of patients diagnosed with cancer including brain cancer. However, despite these unprecedented medical successes, patients continue to experience numerous neurologic complications after treatment that interfere with their independence, functionality, and overall quality of life. These include, among others, cognitive impairment, endocrinopathies, peripheral and cranial neuropathies, and vasculopathy. This article describes the long-term neurologic complications cancer survivors commonly experience to increase awareness of these complications and discuss treatments when available. Further research is necessary to understanding of mechanisms of neurologic injury and advance diagnosis and treatment. Effective patient education, monitoring, and managing neurologic issues after cancer treatment may improve independence, functionality, and quality of life during survivorship.

Neurocognition and mean radiotherapy dose to vulnerable brain structures: new organs at risk?

BACKGROUND

Children with brain tumors are at high risk of neurocognitive decline after radiotherapy (RT). However, there is a lack of studies on how RT doses to organs at risk (OARs) impacts neurocognition. The aim of this study was to examine dose-risk relationships for mean RT dose to different brain structures important for neurocognitive networks. We explored previously established OARs and potentially new OARs.

METHODS

A sample of 44 pediatric brain tumor survivors who had received proton and/or photon RT were included. Correlations between mean RT doses to OARs and IQ were analyzed. Previously established OARs were cochleae, optic chiasm, optic nerve, pituitary gland, hypothalamus, hippocampus and pons. Potential new OARs for RT-induced neurocognitive decline were cerebellum, vermis and thalamus.

RESULTS

Mean RT dose to different OARs correlated with several IQ subtests. Higher mean RT dose to cochleae, optic nerve, cerebellum, vermis and pons was correlated with lower performance on particularly full-scale IQ (FIQ), Perceptual Reasoning (PRI), Working Memory (WMI) and Processing Speed Index (PSI). Higher mean RT dose to hippocampus correlated with lower performance on processing speed and working memory. For those receiving whole brain RT (WBRT), higher mean RT dose to the pituitary gland correlated with lower performance on working memory.

CONCLUSION

A high dose-risk correlation was found between IQ subtests and mean RT dose in established and potential new OARs. Thus, in the lack of validated dose constraints for vulnerable brain structures, a parsimonious approach in RT planning should be considered to preserve neurocognitive networks.

Neurologic Complications of Cancer Treatment

OBJECTIVE

Advances in cancer treatment have led to extended survival and increased risk of neurologic complications in an aging population. This review summarizes potential neurologic complications in patients who have undergone treatment for neurologic and systemic malignancies.

LATEST DEVELOPMENTS

Radiation and cytotoxic chemotherapy along with other targeted therapies continue to be the mainstay of cancer treatment. These advances in cancer care have led to improved outcomes and increased the need to understand the spectrum of neurologic complications that may arise from treatment. While radiation and older therapies including cytotoxic chemotherapies have side effect profiles that are widely known and well understood, this article serves as a review of the more commonly associated neurologic complications of both traditional and newer treatments being offered to this patient population.

ESSENTIAL POINTS

Neurotoxicity is a common complication of cancer-directed treatment. In general, neurologic complications of radiation therapy are more common in central nervous system malignancies, and neurologic complications of chemotherapy are more common in non-neurologic malignancies. Attempts at prevention, early detection, and intervention remain paramount in the reduction of neurologic morbidity.

Outcomes of systemic bevacizumab in radiation-induced optic neuropathy, case series

PURPOSE

Optic neuropathy is a rare, delayed complication after radiation with no universally accepted treatment modality. We report the outcomes of 6 patients with radiation-induced optic neuropathy (RION) who were treated with systemic bevacizumab.

METHODS

This is a retrospective series of 6 cases of RION, treated with intravenous (IV) bevacizumab. "Improved" or "worse" visual outcomes were defined as a change in best corrected visual acuity of ≥ 3 Snellen lines. Otherwise, the visual outcome was noted as "stable".

RESULTS

In our series, RION was diagnosed 8 to 36 months after radiotherapy. IV bevacizumab was initiated as treatment within 6 weeks of the onset of visual symptoms in 3 cases and after 3 months in the other cases. Although no improvement in visual function was observed, stabilization of vision was noted in 4 of the 6 cases. In the other 2 cases, the level of vision declined from counting fingers to no light perception. In 2 cases, bevacizumab treatment was discontinued prior to completion of the planned course due to renal stone formation or worsening of renal disease. One patient developed ischemic stroke 4 months after bevacizumab completion.

CONCLUSION

Systemic bevacizumab may stabilize vision in some patients with RION, though the limitations of our study do not allow us to draw this conclusion definitively. Therefore, the risks and potential benefits of using IV bevacizumab should be considered in each individual case.

Definitive-intent (chemo)radiotherapy for sinonasal undifferentiated carcinoma

OBJECTIVE

The current study aimed to investigate the value of definitive-intent (chemo)radiotherapy in treating sinonasal undifferentiated carcinoma (SNUC) in a single institution.

METHODS

The medical records of 21 patients with SNUC treated with definitive-intent (chemo)radiotherapy between 2011 and 2021 in one single institution were retrospectively reviewed. We analyzed the treatment efficiency and long-term survivals.

RESULTS

A total of 21 patients were included in this cohort, 12 patients presented with T4 stage at diagnosis, and 6 in T1/T2, 3 in T3 stage. Nine patients (42.9%, 9/21) showed cervical lymph node metastases. All the patients were scheduled to receive definitive (chemo)radiotherapy and five patients had been performed surgery for residual tumor after (chemo)radiotherapy. 66.7% (14/21) of patients had a complete response after the completion of treatment, 23.8% (5/21) of partial response, one of stable disease, and one of progressed disease. The 3-year overall survival of the entire group were 86.2%, and the 3-year progress-free survival were 66.3%, respectively. 52.4% of the patients (11/21) presented orbit invasion, compared with patients without orbit invasion, the patients who had orbit invasion were not found to have significantly poor 3-year overall survival (87.5% vs 83.3%, p = 0.38) and 3-year progression-free survival (75.0% vs 55.3%, p = 0.59).

CONCLUSION

Definitive-intent (chemo)radiotherapy could be the preferred treatment for patients with advanced SNUC, and salvage surgery should be performed for the lesions showing stable disease, progressed disease, or residual tumor.

ADVANCES IN KNOWLEDGE

The value of definitive chemoradiotherapy in treating sinonasal undifferentiated carcinoma.

Radiation-induced optic neuropathy: a review

Radiation is a commonly used treatment modality for head and neck as well as CNS tumours, both benign and malignant. As newer oncology treatments such as immunotherapies allow for longer survival, complications from radiation therapy are becoming more common. Radiation-induced optic neuropathy is a feared complication due to rapid onset and potential for severe and bilateral vision loss. Careful monitoring of high-risk patients and early recognition are crucial for initiating treatment to prevent severe vision loss due to a narrow therapeutic window. This review discusses presentation, aetiology, recent advances in diagnosis using innovative MRI techniques and best practice treatment options based on the most recent evidence-based medicine.