Neuroinflammation After Stereotactic Radiosurgery-Induced Brain Tumor Disintegration Is Linked to Persistent Cognitive Decline in a Mouse Model of Metastatic Disease

PURPOSE

Improved efficacy of anticancer therapy and a growing pool of survivors give rise to a question about their quality of life and return to premorbid status. Radiation is effective in brain metastasis eradication, although the optimal approach and long-term effects on brain function are largely unknown. We studied the effects of radiosurgery on brain function.

METHODS AND MATERIALS

Adult C57BL/6J mice with or without brain metastases (rat 9L gliosarcoma) were treated with cone beam single-arc stereotactic radiosurgery (SRS; 40 Gy). Tumor growth was monitored using bioluminescence, whereas longitudinal magnetic resonance imaging, behavioral studies, and histologic analysis were performed to evaluate brain response to the treatment for up to 18 months.

RESULTS

Stereotactic radiosurgery (SRS) resulted in 9L metastases eradication within 4 weeks with subsequent long-term survival of all treated animals, whereas all nontreated animals succumbed to the brain tumor. Behavioral impairment, as measured with a recognition memory test, was observed earlier in mice subjected to radiosurgery of tumors (6 weeks) in comparison to SRS of healthy brain tissue (10 weeks). Notably, the deficit resolved by 18 weeks only in mice not bearing a tumor, whereas tumor eradication was complicated by the persistent cognitive deficits. In addition, the results of magnetic resonance imaging were unremarkable in both groups, and histopathology revealed changes. SRS-induced tumor eradication triggered long-lasting and exacerbated neuroinflammatory response. No demyelination, neuronal loss, or hemorrhage was detected in any of the groups.

CONCLUSIONS

Tumor disintegration by SRS leads to exacerbated neuroinflammation and persistent cognitive deficits; therefore, methods aiming at reducing inflammation after tumor eradication or other therapeutic methods should be sought.

Gliosarcoma of the pineal region with cerebellar metastasis: case illustration

A very rare case of gliosarcoma of the pineal region with cerebellar metastasis is presented. A few cases of glioblastoma and fibrosarcoma have already been published however there was no reported case with gliosarcoma at the pineal region even with cerebellar metastases.

Gliosarcoma with multiple extracranial metastases: case report and review of the literature

Gliosarcoma is a rare malignant neoplasm of the central nervous system with a propensity for metastasis. There are fewer than 20 reported cases of extracranial metastases of gliosarcoma with the majority of cases reflecting a tendency for hematogenous dissemination. Here we describe the case of a 47-year-old man who developed pervasive extracranial metastases from a temporal gliosarcoma following radio- and chemotherapy for a primary glioblastoma. The patient initially presented with progressively worsening headaches, left-sided weakness and numbness associated with right temporo-parietal mass for which he underwent craniotomy with stereotactic gross-total excision. Two months postoperatively, interstitial brachytherapy and external beam radiotherapy were initiated. The patient initially declined chemotherapy. The tumor recurred twice and the patient underwent re-operation and multiple courses of chemotherapy; histopathological diagnosis remained glioblastoma multiforme. Nineteen months following initial resection the patient's clinical status deteriorated and CT scan demonstrated multiple intrathoracic, hepatic and splenic lesions. Postmortem examination revealed widespread, infiltrating gliosarcoma with intravascular gliomatosis and extensive visceral metastases. This is the first report of pervasive extracranial metastases to numerous sites, several of which have not been previously reported. The histogenesis and the potential role of therapeutic irradiation in the development of gliosarcoma are briefly reviewed.

Cavernous sinus tumor model in the canine: a simulation model for cavernous sinus tumor surgery

OBJECTIVE

The recent limitations of working hours for neurosurgical trainees carry the risk of decreasing the amount of microsurgical experience. In the absence of enough surgical exposure to some pathological states, an alternative option of a more continuous source of tactile and visual experience that simulates the real-life state is needed. To help with this problem, we established a cavernous sinus tumor model in the canine.

METHODS

A gliosarcoma cell line that was harvested from a tumor model in nude mice was implanted in six mongrel dogs. In the first group (two dogs), the cell line was implanted in the dural leaflets of the cavernous sinus. (Immunosuppression was used in one dog.) In the second group (four dogs), the cell line was implanted in the region of the gasserian ganglion. (Immunosuppression was used in all four dogs.) The condition of each dog was followed through neurological examinations and serial magnetic resonance imaging. The cavernous sinus region later was explored, after which the dogs were later killed and histopathological evaluations of the cavernous sinus region was carried out.

RESULTS

The initial cell line implanted within the dural leaflets of the cavernous sinus showed no evidence of tumor growth. The tumor grew in all four dogs that had the gliosarcoma cell line implanted in the region of the gasserian ganglion. The clinical and radiological features as well as the experience of the surgical dissection of these tumors simulated cavernous sinus tumors in humans.

CONCLUSION

We established the first cavernous sinus tumor model in the canine. This model simulates the real-life pathological state, and it can be used as an alternative source of surgical experience to advance surgical skills.

Gliosarcoma with areas of primitive neuroepithelial differentiation and extracranial metastasis

We report a case of gliosarcoma with areas of primitive neuroepithelial differentiation arising in the temporal lobe of a 53-year-old man. The sarcomatous component of this tumor was perivascular in its distribution and showed expression of factor VIII-related antigen, smooth muscle actin and CD34. The primitive neuroepithelial component possessed a small cell morphology and showed expression of neuronal antigens. Strong expression of p53 was demonstrated throughout the tumor with only focal weak expression of epidermal growth factor receptor. The tumor developed widespread extraneural metastases 5 months after surgical resection of the primary tumor. Histological examination of the liver metastases showed them to consist predominantly of the primitive neuroepithelial component. We believe this to be a novel pattern of differentiation in a gliosarcoma which in this case was associated with an aggressive metastatic potential.

Extraneural metastases of primary brain tumors

Extraneural metastasis (ENM) of primary brain tumors is arare occurence. Based on acritical analysis of the literature the present review focuses on illustrating special common features of these tumors with regard to immunological, cytokinetical and tumorbiological issues. In this respect much can be learned from the specific conditions following organ transplantation which is extensively discussed.

Gliosarcoma metastatic to the cervical spinal cord: case report and review of the literature

BACKGROUND

We describe a case of an intramedullary metastasis to the cervical spinal cord from a temporal gliosarcoma.

CASE DESCRIPTION

A 48-year-old man with known temporal lobe gliosarcoma presented with a new onset of ipsilateral hemiparesis. A MRI scan revealed the presence of an intramedullary lesion in the spinal cord behind the body of C2. Despite repeated craniotomy, radiation, and chemotherapy, the patient succumbed to a rapidly progressive disease.

CONCLUSION

The case illustrates the ability of gliosarcoma to metastasize to other locations in the neuroaxis. We believe this to be the first case report of an intramedullary spinal cord metastasis from a gliosarcoma. The pathological features and available literature are reviewed.

October 1998--61 year old male with brain tumor and oral, lung, and palpebral masses

In Jan. 97 a gliosarcoma was diagnosed in a 61-year- old man after a 6-month history with neurological deficits. A total physical examination, laboratory tests, chest x-ray and abdominal ultrasound scanning revealed no gross abnormalities. Surgery was followed by brain radiation therapy and 6 months later there were metastases to the oral cavity, right palpebra and both lungs. The histological findings of the oral and palpebral metastases revealed only the sarcomatous component. We are aware of 15 cases of gliosarcoma with extraneural metastases, and in 4 of these, the metastases contained only the sarcomatous component. We believe that our case represents the fifth case of pure sarcomatous metastases.

Therapeutic efficiency and safety of a second-generation replication-conditional HSV1 vector for brain tumor gene therapy

A second-generation replication-conditional herpes simplex virus type 1 (HSV) vector defective for both ribonucleotide reductase (RR) and the neurovirulence factor gamma34.5 was generated and tested for therapeutic safety and efficiency in two different experimental brain tumor models. In culture, cytotoxic activity of this double mutant HSV vector, MGH-1, for 9L gliosarcoma cells was similar to that of the HSV mutant, R3616, which is defective only for gamma34.5, but was significantly weaker than that of the HSV mutant hrR3, which is defective only for RR. The diminished tumoricidal effect of the gamma34.5 mutants could be accounted for by their reduced ability to replicate in 9L cells. The MGH-1 vector did not achieve significant prolongation of survival in vivo in the syngeneic 9L rat gliosarcoma model for either single brain tumor focus or multiple intracerebral and leptomeningeal tumors, when the vector was applied intratumorally or intrathecally, respectively, and with or without subsequent ganciclovir (GCV) treatment. In identical 9L brain tumor models with single and multiple foci, application of hrR3 with or without GCV was previously shown to result in marked long-term survival. Contrary to the findings with intrathecal injection of hrR3, no vector-related mortality was observed in any animals treated with MGH-1. Thus, in these rat brain tumor models, the double mutant, replication-conditional HSV vector MGH-1 showed a higher therapeutic safety than the RR-minus vector, hrR3, but had clearly decreased therapeutic efficiency compared to hrR3. The development of new HSV vectors for brain tumor gene therapy will require a balance between maximizing therapeutic efficacy and minimizing toxicity to the brain. Standardized application in brain tumor models as presented here will help to screen new HSV vectors for these requirements.

Intrathecal 5-[125I]iodo-2'-deoxyuridine in a rat model of leptomeningeal metastases

The antitumor effect of 5-[125I]iodo-2'-deoxyuridine (125IUdR) was examined in a rat model of leptomeningeal metastases. In this model, 50% of rats develop paralysis of hind limbs. In 9.20 +/- 0.02 days and die in 12.1 +/- 2.1 days after intrathecal (i.t.) implantation of 5 x 10(5) 9L rat gliosarcoma cells.

METHODS

Three days after implantation of 9L gliosarcoma cells, 125IUdR was administered intrathecally to rats as: (a) a single injection (500 microCi/rat), (b) five daily injections (100 microCi/day) or (c) a continuous 5-day infusion (0.5 microliter/hr, total of 500 microCi), and the animals were monitored for the onset of paralysis. Control groups received physiologic saline. For biodistribution studies, rats received a bolus injection of 125IUdR (10 microCi) 5 days after tumor-cell implantation and were killed 1, 8, 24, and 48 hr later. Tissues and organs, including the spinal cord, were isolated and their radioactive content determined. The results were expressed as percent injected dose per gram of wet tissue. Histological sections of the spinal cord were also prepared and used for autoradiographic detection of DNA-incorporated 125IUdR.

RESULTS

Treatment with i.t. administered 125IUdR (500 microCi/rat) significantly (p < or = 0.005) prolonged the median time of paralysis to 11.2 +/- 0.1, 12.3 +/- 0.1 and 15.2 +/- 0.4 days for the single-dose, five daily injections and continuous infusion groups, respectively. Radioactivity cleared rapidly from all tissues except the thyroid and tumor cells growing within the spinal cord. Autoradiography demonstrated that normal cells in the tumor-bearing spinal cord were void of radioactivity.

CONCLUSION

The results suggest that a selective antitumor effect could be achieved in treating leptomeningeal metastases with i.t. administered 125IUdR.

Herpes vector-mediated delivery of marker genes to disseminated central nervous system tumors

The present study investigated the ability of a recombinant herpes simplex virus type 1 (HSV) vector to deliver genes into disseminated brain tumor foci through intrathecal injection of the vector. The animal model was designed to simulate brain tumors with cerebrospinal fluid (CSF) metastases, which are found especially in the pediatric population. 9L gliosarcoma cells were injected both into the right frontal lobe and in through the cisterna magna of adult rats. The HSV vector, hrR3, was inoculated intrathecally 5 days later. This vector is defective in the gene for ribonucleotide reductase, and, therefore, replicates preferentially in dividing cells; it retains an intact HSV-thymidine kinase gene (HSV-tk). Two days after injection of the vector, immunohistochemical staining for HSV thymidine kinase (HSV-TK) revealed expression in frontal tumors, as well as in leptomeningeal tumor foci along the entire neuroaxis. HSV-TK-immunopositive cells were most frequent in small tumors contacting the CSF pathways. Frontal lobe tumors showed the highest density of HSV-TK-immunopositive cells around their periphery with little expression in central parts. Some paraventricular neurons temporarily showed HSV-TK-immunolabeling at this early time point. The number of HSV-TK-immunopositive tumor cells markedly decreased 5 days after injection of the HSV vector. In all animals, some toxicity was observed in the first 2-4 days after virus injection with extensive leptomeningeal inflammation. In conclusion, intrathecal application of HSV vectors can mediate widespread transfer of the therapeutic HSV-tk gene into disseminated tumors throughout the brain and CSF pathways. Although there was marked toxicity associated with intrathecal injection of this vector, this mode of gene delivery offers a promising approach for treatment of CSF-metastases in conjunction with development of less toxic vectors.