Autopsy verifies demyelination and lack of vascular damage in partially reversible radiation myelopathy

Metabolic and Toxic Myelopathies

Metabolic and toxic causes of myelopathy form a heterogeneous group of disorders. In this review, we discuss the causes of metabolic and toxic myelopathies with respect to clinical presentation, pathophysiology, diagnostic testing, treatment, and prognosis. This review is organized by temporal course (hyperacute, acute, subacute, and chronic) and etiology (e.g., nutritional deficiency, toxic exposure). Broadly, the myelopathies associated with dietary toxins (neurolathyrism, konzo) and decompression sickness present suddenly (hyperacute). The myelopathies associated with heroin use and electrical injury present over hours to days (acutely). Most nutritional deficiencies (cobalamin, folate, copper) and toxic substances (nitrous oxide, zinc, organophosphates, clioquinol) cause a myelopathy of subacute onset. Vitamin E deficiency and hepatic myelopathy cause a chronic myelopathy. Radiation- and intrathecal chemotherapy-induced myelopathy can cause a transient and/or a progressive syndrome. For many metabolic and toxic causes of myelopathy, clinical deficits may stabilize or improve with rapid identification and treatment. Familiarity with these disorders is therefore essential.

Radiation Induced Demyelination in Cervical Spinal Cord of the Head and Neck Cancer Patients after Receiving Radiotherapy

Background:

Cervical spinal cord is important and radiosensitive. It is the most critical organ for the head and neck (H&N) cancer patients during radiotherapy. If the delivered dose to the cord is more than tolerance dose, demyelination may occur.

Objective:

Current study aims to analyze the post radiotherapy status of cord in the H&N cancer patients

Material and Methods:

In this analytical study, sixty patients who received more than 50 Gray (Gy) dose for more than 10 cm length of spinal cord participated in the study. All the patients were clinically examined and magnetic resonance imaging (MRI) was performed for patients who had demyelination symptoms. Adequate medical management was provided for all the patients having demyelination.

Results:

Out of sixty patients, ten cases were reported with demyelination symptoms, and only six cases gave consent for this study. One patient was found to have irreversible demyelination while five patients had reversible demyelination.

Conclusion:

Demyelination may occur if long segment spinal cord receives dose more than tolerance limit. However target dose should not be compromised up to 54 Gy to spinal cord.

External beam radiotherapy in thyroid carcinoma: clinical review and recommendations of the AIRO "Radioterapia Metabolica" Group

The therapeutic approach to thyroid carcinoma usually involves surgery as initial treatment. The use of external beam radiotherapy (EBRT) is limited to high-risk patients and depends on clinical stage and histologic type. Different behavior patterns and degrees of aggressiveness of thyroid carcinomas require different management for differentiated, medullary, and anaplastic carcinoma. However, the role of EBRT is an issue of debate. Most clinical studies are retrospective and based on single-institution experiences. In this article, we review the main literature and give recommendations for the use of EBRT in thyroid carcinoma on behalf of the "Radioterapia Metabolica" Group of the Italian Radiation Oncology Association.

(18)F-FDG uptake of the spinal cord was decreased after conventional dose radiotherapy in esophageal cancer patients

OBJECTIVE

We retrospectively investigated changes of (18)F-fluorodeocyglucose ((18)F-FDG) uptake in the spinal cord, inside and outside the radiation fields, in patients with esophageal cancer before and after conventional dose radiotherapy.

METHODS

A total of 17 consecutive patients with esophageal cancer (16 males, one female; age 50-83 years, mean 67.0 years), who underwent conventional dose radiotherapy and (18)F-FDG PET/CT before and 5.1 months (range 1.6-8.6 months) after the radiotherapy, were retrospectively evaluated. Sixteen patients had esophageal cancer and one patient had esophageal metastasis from thyroid cancer. Mean standardized uptake values (SUVmean) of the cervical, thoracic (inside and outside the radiation fields) and lumbar spinal cord were measured.

RESULTS

SUVmean of the thoracic spinal cord inside the radiation field was decreased significantly after radiotherapy compared to those before radiotherapy (p < 0.001). SUVmean of the cervical spinal cord showed the same trend but it was not statistically significant (p = 0.051). SUVmean of the thoracic spinal cord outside the radiation field and the lumbar spinal cord did not differ significantly before and after the radiotherapy (p = 0.146 and p = 0.701, respectively).

CONCLUSIONS

The results suggest that glucose metabolism of the spinal cord is decreased in esophageal cancer patients after conventional dose radiotherapy.

Potential applications of imaging and image-guided radiotherapy for brain metastases and glioblastoma to improve patient quality of life

Treatment of glioblastoma multiforme (GBM) and brain metastasis remains a challenge because of the poor survival and the potential for brain damage following radiation. Despite concurrent chemotherapy and radiation dose escalation, local recurrence remains the predominant pattern of failure in GBM most likely secondary to repopulation of cancer stem cells. Even though radiotherapy is highly effective for local control of radio-resistant tumors such as melanoma and renal cell cancer, systemic disease progression is the cause of death in most patients with brain metastasis. Preservation of quality of life (QOL) of cancer survivors is the main issue for patients with brain metastasis. Image-guided radiotherapy (IGRT) by virtue of precise radiation dose delivery may reduce treatment time of patients with GBM without excessive toxicity and potentially improve neurocognitive function with preservation of local control in patients with brain metastasis. Future prospective trials for primary brain tumors or brain metastasis should include IGRT to assess its efficacy to improve patient QOL.

[Case of recurrent delayed radiation myelopathy with 5-year remission interval]

We report a 47-year-old woman with relapsed delayed radiation myelopathy (DRM), occurring 5 years and 10 years after radiation therapy for nasopharyngeal carcinoma at 37 years old. Sensations of pain and temperature had been disturbed in the right leg since 42 years old. MRI showed Gadolinium-enhanced lesion as a ring-like-enhancement of the spinal cord at C1-2 on T1-weighted image (T1WI), with high signal area and swelling of the spinal cord at the upper C1 to C6 areas on T2-weighted image. We diagnosed her as having DRM after considering the differential diagnosis, e.g., multiple sclerosis, spinal tumor and other neurological diseases. Her sensory symptoms quickly improved following therapy with prednisolone and warfarin. Although she remained healthy for a few years, dysesthesia of the neck on the right side appeared 5 years later after the first clinical occurrence. At this time, MRI demonstrated Gadolinium-enhanced lesion as a ring-like enhancement of the spinal cord at C2 on T1WI. but the area also differed from that of previous lesion; a high signal area and swelling of the spinal cord was also seen on FLAIR image of the medulla and upper C1 to C6. For recurrence of DRM, we administered prednisolone and warfarin. Thereafter, the patient recovered and the spinal cord lesion on MRI decreased markedly. The clinical course demonstrated that administration of prednisolone and warfarin might be effective for relapsed DRM.

Stem cells for the treatment of myelin loss

Treatment of myelin loss is particularly suited to therapeutic strategies based on cell replacement. Demyelination represents a defined and functionally debilitating deficit, and remyelination can be accomplished by supplying regions of demyelination with myelinogenic cell populations. Clinical interest in stem cells as a source of myelinogenic cells arises from their ability to provide an apparently unlimited cell supply for transplantation, and from recent demonstrations that they can be directed to myelinogenic phenotypes with high purity. Here, I present the emerging perspective that stem-cell-mediated remyelination of the adult CNS is a viable therapeutic strategy, and discuss the challenges to remyelination posed by the environment of acute and chronic injuries.