Fulminant radiation-induced necrosis after stereotactic radiation therapy to the posterior fossa. Case report and review of the literature

Cyst Formation Following Radiosurgery for AVMs: Report of 3 Cases

Background:

Stereotactically-focused radiosurgery (SRS) for the treatment of arteriovenous malformations (AVM) has been in widespread use for over two decades. Over this timeframe the indications for treatment, standardization of radiation dosage, and the results expected from treatment have been elaborated. Less well known are the long-term complications associated with SRS. We report three patients who had SRS for the treatment of AVM who developed a cyst at the site of treatment as a late complication.

Methods:

From 201 patients treated by SRS for an AVM, three developed a cyst at the treatment site. Their clinical presentation, the characteristics of the AVMs and the treatment were reviewed, as well as similar cases gleaned from the literature.

Results:

Three women, aged 28-43 years, had an AVM treated by: craniotomy and clipping of arterial feeders followed by SRS, by craniotomy for resection followed by SRS or by endo vascular embolization and SRS. The patients did well following treatment but two of them developed a symptomatic and the other an asymptomatic cyst at the treatment site 3-19 years later. The symptomatic patients underwent marsupialization of the cyst and the other is under observation.

Conclusion:

Stereotactic radiosurgery is an established and safe treatment for patients with AVMs. Delayed cyst formation can occur many years after treatment and long term follow-up is indicated in patients whose AVM has been treated with SRS.

Repeated treatments with bevacizumab for recurrent radiation necrosis in patients with malignant brain tumors: a report of 2 cases

Bevacizumab is expected to constitute a new treatment modality for radiation necrosis. In the present cases, we observed a recurrence of radiation necrosis after temporary improvement by bevacizumab treatment. Re-treatment with bevacizumab controlled the necrosis again. A 39-year-old male and a 57-year-old female were diagnosed with glioblastoma and lung cancer metastasis, respectively. The former patient underwent partial resection of the glioblastoma, followed by boron neutron capture therapy (BNCT) and 30 Gy of fractionated X-ray radiotherapy. Eleven months after BNCT, he suffered from left hemiparesis and convulsions with enlargement of a perifocal edema. The latter patient underwent stereotactic radiosurgery twice for the same tumor. Three months after the second radiosurgery, she had an uncontrollable convulsion and right hemiplegia with a massive perifocal edema. Both lesions were suggested to be radiation necroses by positron emission tomography using amino acids as a tracer. Neither patient responded to corticosteroids, anticoagulants, or vitamin E. They underwent treatment with 5 mg/kg bevacizumab biweekly, for a total of 6 cycles. The size of the perifocal edema was clearly reduced in response to the treatments. The neurological status of the patients improved concomitant with therapy. However, the clinical status of both patients was aggravated several months after the bevacizumab was stopped, and the perifocal edemas enlarged again. The patients underwent a second treatment with bevacizumab, and the perifocal edemas again decreased. Although radiation necrosis may recur several months after bevacizumab treatment, repeated bevacizumab treatments also appear to be effective.

Radiation necrosis of the brain after radiosurgery for vestibular schwannoma

OBJECTIVE

The objective of this study was to obtain a better understanding of radiation-induced brain necrosis after stereotactic radiation therapy for vestibular schwannomas.

STUDY DESIGN

We conducted a retrospective case analysis.

SETTING

The study took place at a tertiary referral center.

PATIENTS

We report on the case of a patient treated with stereotactic radiation who developed radiation-induced necrosis of the ipsilateral temporal lobe.

INTERVENTION

The various interventions in patients with radiation-induced necrosis include steroid treatment, decompression, and hyperbaric oxygen therapy; these are discussed briefly in this article. Owing to the limited symptoms in our patient, she was observed.

MAIN OUTCOME MEASURE

The outcome measure that we evaluated was radiation-induced necrosis of the brain after stereotactic radiation therapy for a vestibular schwannoma.

RESULTS

Patients who undergo stereotactic radiation therapy for vestibular schwannomas are at risk for radiation-induced brain necrosis.

CONCLUSION

We support the development of a national database that would track the long-term complications of stereotactic radiation therapy to help patients make a more informed decision for the treatment of their vestibular schwannomas.

Effect of prophylactic hyperbaric oxygen treatment for radiation-induced brain injury after stereotactic radiosurgery of brain metastases

PURPOSE

The purpose of the present study was to evaluate the prophylactic effect of hyperbaric oxygen (HBO) therapy for radiation-induced brain injury in patients with brain metastasis treated with stereotactic radiosurgery (SRS).

METHODS AND MATERIALS

The data of 78 patients presenting with 101 brain metastases treated with SRS between October 1994 and September 2003 were retrospectively analyzed. A total of 32 patients with 47 brain metastases were treated with prophylactic HBO (HBO group), which included all 21 patients who underwent subsequent or prior radiotherapy and 11 patients with common predictors of longer survival, such as inactive extracranial tumors and younger age. The other 46 patients with 54 brain metastases did not undergo HBO (non-HBO group). The radiation-induced brain injuries were divided into two categories, white matter injury (WMI) and radiation necrosis (RN), on the basis of imaging findings.

RESULTS

The radiation-induced brain injury occurred in 5 lesions (11%) in the HBO group (2 WMIs and 3 RNs) and in 11 (20%) in the non-HBO group (9 WMIs and 2 RNs). The WMI was less frequent for the HBO group than for the non-HBO group (p = 0.05), although multivariate analysis by logistic regression showed that WMI was not significantly correlated with HBO (p = 0.07). The 1-year actuarial probability of WMI was significantly better for the HBO group (2%) than for the non-HBO group (36%) (p < 0.05).

CONCLUSIONS

The present study showed a potential value of prophylactic HBO for the radiation-induced WMIs, which justifies further evaluation to confirm its definite benefit.

Recurrent late cerebral necrosis with aggressive characteristics after radiosurgical treatment of an arteriovenous malformation

✓Late cerebral radiation necrosis usually occurs within 3 years of stereotactic radiosurgery. The authors report on a case of recurrent radiation necrosis with rapid clinical deterioration and imaging findings resembling those of a malignant glioma. This 68-year-old man, who had a history of a left posterior temporal and thalamic arteriovenous malformation (AVM) treated with linear accelerator radiosurgery 13 years before presentation and complicated by radiation necrosis 11 years before presentation, exhibited new-onset mixed aphasia, right hemiparesis, and right hemineglect. Imaging studies demonstrated hemorrhage and an enlarging, heterogeneously enhancing mass in the region of the previously treated AVM. The patient was treated medically with corticosteroid agents, and stabilized temporarily. Unfortunately, his condition worsened precipitously soon thereafter, requiring the placement of a shunt for relief of obstructive hydrocephalus. Further surgical intervention was offered, but the patient’s family opted for hospice care instead. The patient died 10 weeks after initially presenting to the authors’ institution, and the results of an autopsy demonstrated radiation necrosis.

Symptomatic radiation necrosis can occur more than a decade after stereotactic radiosurgery, necessitating patient follow up during a longer period of time than currently practiced. Furthermore, there is a need for more careful reporting on the natural history of such cases to clarify the pathogenesis of very late and recurrent radiation necrosis after radiosurgery and to define patient groups with a higher risk for these entities.

Radionecrosis of the Inferior Occipital Lobes With Altitudinal Visual Field Loss After Gamma Knife Radiosurgery

A patient had bilateral superior altitudinal visual field defects because of radionecrosis of the inferior occipital lobes after gamma knife radiosurgery for a recurrent atypical cerebellar meningioma. Although radionecrosis of the anterior visual pathway has been well-documented, this is the first report of visual field loss associated with occipital lobe radionecrosis. The treatment dose this patient received is within the range of predicted tolerable radiosurgical dosing, although this patient was at increased risk for radionecrosis secondary to previous external beam radiotherapy. By offering an effective, noninvasive treatment, radiosurgery has changed the management of intracranial lesions. Radiosurgery targets a discrete volume of tissue and relatively spares the surrounding normal tissue. Radiation injury, or radionecrosis, is the only significant complication of radiosurgery (). We present a case of bilateral occipital lobe radionecrosis after gamma knife surgery that resulted in bilateral superior altitudinal defects.