Tumors of the spine and spinal cord.

OBJECTIVES: To provide an overview of spinal cord neoplasms with a focus on location, histology, pathophysiology, diagnosis, treatment and nursing assessment and management. DATA SOURCES: Published books and peer-reviewed articles. CONCLUSIONS: Tumors of the spine and spinal cord are rare, and they can have grave implications for the patient. The key in the management of spinal cord tumors is their timely diagnosis and treatment to preserve function. IMPLICATIONS FOR NURSING PRACTICE: A thorough nursing assessment and timely intervention can have a positive impact on the outcome of patients with tumors of the spine and spinal cord.

What is the etiology of human brain tumors? A report on the first Lebow conference.

Although the conference could not provide a definitive etiologic explanation for the observed increase in incidence of human brain tumors, particularly among the elderly, nevertheless, this interdisciplinary gathering of prominent scientists and clinicians proved invaluable in identifying new avenues of research. Clearly, the puzzle of what causes brain tumors is highly complex, involving links to ionizing/electromagnetic radiation, familial, and dietary factors. The Lebow Conference provided an important scientific framework upon which to build further research studies, and its influence will be felt for years to come.

Acute changes in glucose uptake after treatment: the effects of carmustine (BCNU) on human glioblastoma multiforme.

Sequential positron emission tomographic scans with [18F]-2-fluorodeoxyglucose (PET-FDG) were performed on 6 patients with glioblastoma multiforme who were treated with adjuvant BCNU. Scans were acquired before and 24 hours after BCNU. All patients had prior brain irradiation. Ratios between the maximal tumor FDG uptake and the contralateral white matter FDG uptake, the glucose uptake ratio, were determined. Percent changes in the glucose uptake ratio between the baseline scan and the 24 hour post-treatment scan were of prognostic significance. Patients with the largest percent changes in FDG uptake had the shortest survival. In contrast, neither the baseline glucose uptake ratio nor the visual tumor grade accurately predicted length of survival.

Blood flow asymmetry in carotid occlusive disease.

Patterns of anterior border zone (ABZ) and middle cerebral artery (MCA) cerebral blood flow (CBF) asymmetry were readily seen during both normocapnic room air (RA) and induced hypercapnic (CO2) inhalation using fluoro-methane and a multislice, high-resolution positron scanner. Wilcoxon two-sample rank testing showed symptomatic-over-nonsymptomatic CBF ratios for unilateral greater than 75% carotid stenosis patients (n = 8) to be 1.05 +/- 0.07 (p less than 0.008 as compared with control of 0.97 +/- 0.02) ABZ RA, 0.98 +/- 0.11 ABZ Co2, 0.98 +/- 0.04 MCA RA, and 0.98 +/- 0.06 MCA CO2. Unilateral carotid occlusion patients (n = 8) had ratios of 0.90 +/- 0.16 ABZ RA, 0.81 +/- 0.19 (p less than 0.002) ABZ CO2, 0.90 +/- 0.12 and 0.89 +/- 0.13 for MCA RA and CO2, respectively (both p less than 0.008 as compared with control 0.99). These preliminary results suggest an upgrade of autoregulation (ie, very high ratio) in the ABZ of high-grade stenosis patients during normocapnia. CBF was preferentially higher on the symptomatic side and then either did not increase or paradoxically fell in response to hypercapnia. In comparison, carotid occlusion patients had low ABZ and MCA ratios during normocapnia, also unable to increase with hypercapnia. The fall in ratios from normocapnia to hypercapnia indicates that these areas, already subject to maximal vasodilation, fail to increase CBF or actually become hypoperfused following induced hypercapnia. These results aid in understanding the concept of "hemodynamic significance."

Defining the role of radiosurgery in the management of brain metastases.

The role of stereotactic radiosurgery in the management of recurrent and newly diagnosed brain metastases was evaluated prospectively. From December 1988 to March 1991, 58 lesions in 40 patients were treated with accelerator-based stereotactic radiosurgery. All patients were followed for a minimum of 6 months or to death. The primary purpose was to determine the impact of radiosurgery on local control and its subsequent effects on quality of life. An overall tumor control rate of 82% with a complete response rate of 43% were achieved. As anticipated, the response rate for smaller tumors was substantially better than that for larger tumors (78% for lesions < 2 cm3; 50% for lesions > or = 10 cm3). Although the overall in-field progression rate was 18.5%, only 1/23 (4%) complete responders subsequently recurred. The in-field failure rate is highly comparable with recently published surgical data. Progression outside the brain was noted in two-thirds of patients. One quarter of the deaths were neurologic. The median survival for this minimally selected patient population was 6.5 months. Stereotactic radiosurgery was also associated with improved quality of life as measured by Karnofsky score, neurologic function, and steroid dependence. Long-term steroid dependence was encountered in only four patients. We conclude that stereotactic radiosurgery can be used effectively in patients with brain metastases. In this series, a high tumor response rate was achieved which was associated with improved quality of life.

Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) of brain tumors.

In summary, PET and SPECT are versatile imaging modalities capable of providing dynamic information regarding the metabolism and physiology of brain and brain tumor. PET and SPECT are useful adjuncts to MRI and CT scanning in the important clinical areas of presurgical estimations of tumor grade. In addition, PET can be used to differentiate tumor necrosis from recurrence noninvasively, which is important for patient management. PET also may prove useful in early assessments of metabolic and physiologic changes in brain tumors following treatment and in monitoring drug delivery to tumor. Studies of drug delivery to and metabolic and physiologic responses of brain and brain tumor to treatment provide a quantitative handle on tumor response and patient prognosis. The ability to acquire such quantitative data may lead in the future to more efficient brain tumor treatment algorithms and to the development of more effective treatment protocols.

Early changes in tumor metabolism after treatment: the effects of stereotactic radiotherapy.

Four patients with intracranial neoplasms, two with malignant gliomas and two with brain metastases, were treated with stereotactic radiotherapy. Patients received between 15 and 27.5 Gray of photon irradiation to the central tumor target point; the 80% isodose line covered the periphery of the tumor as determined by contrast enhanced computed tomography. Patients underwent a sequence of three Positron Emission Tomographic scans using [18F]-fluorodeoxyglucose (PET-FDG)--a baseline scan the day before treatment, and follow-up scans 1 and 7 days after treatment. Ratios between the maximal tumor regional cerebral metabolic rate for glucose (rCMRGlu) (T*) and the contralateral remote white matter rCMRGlu (RW), that is, the glucose uptake ratio (T*/RW), were calculated. The percent change in ratios relative to each patient's baseline scan were calculated. Ratios increased 25% to 42% 1 day post-radiotherapy, then decreased to between 10% above and 12% below the baseline value 7 days post-radiotherapy. The T*/RW increased acutely after stereotactic radiotherapy in a fashion similar to that previously described following chemotherapy with a complex multi-drug regimen. A common metabolic pathway may underlie the increase in T*/RW after these different treatments.

Blood flow reactivity to hypercapnia in strictly unilateral carotid disease: preliminary results.

To show relationship between degree of carotid arterial stenosis and cerebral blood flow reactivity (RES%) to induced hypercapnia, fluorine-18-fluoromethane and positron emission tomography (PET) was used to study 18 patients with carotid distribution transient ischaemic attacks (TIA), all free of stroke, who had angiographic-proven unilateral arterial disease. Non-involved carotid arteries were either normal or had non-stenotic plaque. Either normal arteries or nonstenotic ulcerations in the symptomatic carotid arteries were present in five of 18 (28%), ipsilateral carotid stenosis from 50-99% was present in eight of 18 (44%), and ipsilateral internal carotid occlusion was present in five of 18 (28%) patients. In comparison with 14 normal controls, all patients with symptomatic middle cerebral artery (MCA) flow territories had significantly lower mean (SEM) RES% [5.0' (0.2) vs 4.0 (0.9), p less than 0.04]. Symptomatic anterior borderzone (ABZ) RES% was also significantly lower [4.6 (0.4) vs 3.3 (0.9), p less than 0.04], than controls. In patient subgroup comparisons, the 50-99% stenosis subgroup clearly had the lowest MCA RES% [3.4 (0.2)] as well as the lowest ABZ RES% [2.8 (0.4)] on their symptomatic sides. Age, expired pCO2, mean arterial blood pressure, serum glucose, serum haematocrit and number, type and estimated duration of TIAs were not significantly different between subgroups. Linear regression showed a significant relationship between RES% and both measured percentage-stenosis (p = 0.04) and residual luminal diameter (p = 0.05) in symptomatic MCA territories. This approached significance in symptomatic ABZ regions. This preliminary data set suggests that unilateral carotid stenosis can and does result in impaired CO2 reactivity following hypercapnia. The relative normality of CO2 reactivity in those with carotid occlusion is discussed.

Changes in glucose uptake by malignant gliomas: preliminary study of prognostic significance.

Sequential positron emission tomographic scans with [18F]-2-fluorodeoxyglucose (PET-FDG) were performed on 14 patients with malignant gliomas. All patients had prior brain irradiation. Five patients received adjuvant eight-drugs-in-one-day chemotherapy (experimental subjects) and 9 did not (control subjects). Ratios between the maximal tumor regional cerebral metabolic rate for glucose (rCMRGlu) and the contralateral white matter rCMRGlu, the glucose uptake ratio, were determined. Percent changes in the ratio 1 day after chemotherapy in experimental subjects, and 30 days after the baseline scan in controls, were of prognostic significance. In both groups, patients with the largest percent changes in rCMRGlu had the shortest survival. In contrast, the baseline glucose uptake ratio did not predict length of survival.

A phase I study of SR-2508 and cyclophosphamide administered by intravenous injection.

SR-2508, a less lipophilic ane neurotoxic analogue of the nitroimidazole, misonidazole, has exhibited significant chemosensitization properties in preclinical studies with alkylating agents. A phase I trial was carried out to assess toxicity and possible pharmacological interactions of the combination of short infusions of SR-2508 and cyclophosphamide (CP). Patients were randomly assigned to receive either CP alone followed in 3 wk by CP + SR-2508, or CP + SR-2508 followed by CP alone. All additional courses were CP + SR-2508. The maximum tolerated dose of the combination was determined by dose escalation of SR-2508 while the dose of CP remained fixed, initially 1.0 g/m2, and then a second maximum tolerated dose was determined with CP at 1.6 g/m2. One hundred seventeen evaluated courses were administered to 39 patients, the majority of whom had received prior treatment. Somewhat unexpectedly, reversible grade 4 granulocytopenia was the dose-limiting toxicity occurring in four of five evaluable first combination courses at level 6 (SR-2508, 11.3 g/m2; CP, 1.0 g/m2), the initial maximum tolerated dose. SR-2508 enhanced CP-induced myelosuppression as exhibited by the significant difference (p less than 0.001) between the 27 paired courses (CP versus CP + SR-2508) for WBC nadirs over levels 1 to 6. The neurotoxicity encountered was similar to that seen in past clinical trials, being reversible, mild, and usually peripheral in nature. There was one treatment-related death (neutropenic sepsis) on study. No other significant toxicity was seen. SR-2508 exhibited linear pharmacokinetics over the dose range studied. The SR-2508 area under the concentration-time curve increased linearly with dose (r = 0.858; p less than 0.001). No other parameters were dose related. Neither drug appeared to affect the pharmacokinetics of the other, and CP pharmacokinetic values were consistent with those from prior studies. Due to the interaction noted between the two agents and the preclinical data suggesting preferential enhancement of antitumor efficacy under this combination, phase II study appears warranted.

Rasmussen encephalitis: epilepsia partialis continua secondary to chronic encephalitis.

Rasmussen encephalitis is a disease consisting of chronic encephalitis with progressive neurologic deficits and focal intractable seizure activity. The etiology is unknown, but pathologic specimens revealed changes consistent with viral encephalitis. Even though neuro-imaging techniques, such as positron emission tomography and magnetic resonance imaging, offer the prospect of specific, presurgical diagnostic criteria, the initial diagnosis usually is made on a clinical basis. Treatment modalities, including a wide variety of antiepileptic drug therapies and surgical interventions, may result in significant physical and mental impairments. We summarize the clinical presentation, diagnostic considerations, and different treatment protocols in a patient with this rare and debilitating disorder.

Cerebral diaschisis in patients with malignant glioma.

A positron emission tomography study using [18F]-fluorodeoxyglucose was undertaken to identify and quantitate whether diaschisis occurred in cerebral cortex, basal ganglia, or thalamus, as well as in cerebellar cortex and dentate nuclei in patients with malignant glioma. The relationship between diaschisis in these cerebral structures and clinically significant hemiparesis in patients was analysed. A 30% decrease in the regional metabolic rate for glucose in the cerebellar hemisphere contralateral to the tumor, and ipsilateral to the motor deficit, was identified and was statistically significant (p greater than 0.001). Decreased metabolism in the cerebellar hemisphere contralateral to the tumor was not seen in patients without hemiparesis. Parietal lobes affected by tumor had a larger decrease in metabolism than did frontal lobes with tumor (p greater than 0.01). The overall metabolism of the unaffected cerebellar hemisphere, relative to the peak metabolic activity of the brain, was not depressed in patients with tumor. In addition, the activity of subcortical nuclei was relatively unaffected by adjacent tumor or motor deficit.

Glucose uptake by gliomas after treatment. A positron emission tomographic study.

Positron emission tomographic scanning with fludeoxyglucose F 18 (18F-fluorodeoxyglucose) was used to study acute changes in gliomas after chemotherapy. In six experimental subjects, scans were obtained before and at days 1, 7, and 30 after treatment. Five control patients with gliomas who did not undergo chemotherapy had two scans, 1 month apart. Ratios were calculated between peak tumor regional cerebral metabolic rate for glucose and contralateral white matter. The percent change in ratios relative to each patient's baseline scan was calculated. Ratios in three stable controls remained unchanged over the study interval; in two controls it increased 155% and 36% and both died of tumor progression. In experimental subjects, ratios increased 20% to 100% 24 hours after chemotherapy and then decreased until at 28 days they varied between 22% above and 35% below baseline. The increased fludeoxyglucose F 18 uptake at 24 hours could be from uncoupling oxidative phosphorylation or shunting glucose to ribose phosphates for salvage nucleoside synthesis.

Neuropeptide degradation by large vessel and microvessel-derived endothelial cells in vitro: cell surface catabolism of thyrotropin releasing hormone (TRH).

Cell surface ectopeptidase activity of purified, cultured large vessel and microvessel-derived endothelial cells (EC) was studied. Degradation of thyrotropin releasing hormone (TRH), and production of cyclo-His-Pro was significantly increased (P less than 0.001) in large vessel EC compared with microcapillary EC. Since the rate of catabolism in the microvascular capillary bed is 5 times less than that in the large vessel wall, peptide concentrations are likely maintained longer in close proximity to their site of biosynthesis, where they are presumably most active.

"Eight-drugs-in-one-day" chemotherapy administered before and after radiotherapy to adult patients with malignant gliomas.

Thirty-one adult patients with malignant glioma (23 with glioblastoma multiforme, six with anaplastic astrocytoma, and two with brainstem glioma) were treated with up to ten cycles of "eight-drugs-in-one-day" chemotherapy (methylprednisolone 300 mg/m2, vincristine 1.5 mg/m2 [maximum of 2 mg/cycle], CCNU 75 mg/m2, procarbazine 75 mg/m2, hydroxyurea 3000 mg/m2, cisplatin 90 mg/m2, cytosine arabinoside 300 mg/m2, and imidazole carboxamide 150 mg/m2). Chemotherapy was planned as two cycles before and eight cycles after 60 Gy of involved brain irradiation. A total of 117 cycles of chemotherapy was administered. There was one treatment-related death. Myelosuppression was the most frequent toxic effect (leucopenia was less than 1000/mm3 in 9% of cycles and 1000-2500/mm3 in 25%; thrombocytopenia was less than 100,000/mm3 in 33% of cycles). Sixteen patients developed infections requiring treatment, two of which were life-threatening. Five patients suffered ototoxicity. Nausea and vomiting were observed in 35% of patients. A reversible rise in creatinine was observed in five patients. One patient developed a severe motor neuropathy, and three patients developed mild peripheral neuropathies. Three patients had episodes of atrial fibrillation. One new bundle branch block with supraventricular tachycardia was observed in a patient with pulmonary embolus. Five patients developed thrombophlebitis, three of whom had pulmonary emboli. Two patients suffered strokes in areas anatomically separate from their tumor. Eleven patients declined to continue therapy after receiving an average of three cycles. Two had complete, and five had partial responses. The median survival time was 47 weeks. The responses and survival times observed are comparable to less toxic treatment protocols for adults with malignant gliomas.

Cultured brain endothelium inhibits the cytocidal action of natural killer cells on glioma.

The killing of GL26 and YAC-1 cells by natural killer cells (NKC) is reduced in the presence of a monolayer of endothelial cells. This reduction in cytotoxicity correlates with the degree of adhesion between the tumor cells and the endothelial monolayers. The cytotoxicity of NKC toward glioma was 10% when carried out on plastic, but a monolayer of endothelium derived from brain inhibited the cytotoxicity by about 90%. Endothelium from thoracic duct and lung also inhibited cytotoxicity by about 90%, endothelium from aorta inhibited by 55% and that from ovary by only 45%. Cytotoxicity of NKC toward YAC-1 (a control NK target) was 40% on plastic, but a monolayer of endothelium from thoracic duct inhibited the cytotoxicity by 75%. Endothelium from brain and lung inhibited cytotoxicity by about 60%, aorta by 50%, and ovary by 40%. Interactions between tumor cells and the host-organ microvascular endothelium appear to protect neoplastic cells from natural surveillance mechanisms and may play a role in the formation of metastatic tumor deposits.

Eight-drugs-in-one-day chemotherapy in postirradiated adult patients with malignant gliomas.

Fifteen patients, 12 with glioblastoma multiforme and 3 with anaplastic astrocytoma, were treated with "eight-drugs-in-one-day" chemotherapy [methylprednisolone 300 mg/m2, vincristine 1.5 mg/m2 (maximum of 2 mg/cycle), CCNU 75 mg/m2, procarbazine 75 mg/m2, hydroxyurea 3,000 mg/m2, cisplatin 90 mg/m2, cytosine arabinoside 300 mg/m2, and imidazole carboxamide 150 mg/m2]. All patients had prior brain irradiation but none had previous chemotherapy. The population included 10 patients with progressive disease after irradiation and 5 who presented within 2 months of completing radiation. Patients received an average of 5 monthly cycles of chemotherapy. Three patients achieved a complete and 2 a partial response (CR + PRrate was 33%). The median survival time was 46 weeks. Myelosuppression was the dose-limiting toxicity. Leucocyte counts between 2.0-4.5 x 10(3)/mm3 were observed in 40% of patients, between 1.0- less than 2.0 x 10(3)/mm3 in 33%, and less than 1.0 x 10(3)/mm3 in 7%. Platelet counts between 50-130 x 10(3)/mm3 were observed in 27% of patients, and less than 50 x 10(3)/mm3 in 33%. Six patients suffered infections, 4 had reversible renal toxicity, 2 developed paresthesias, and one a debilitating myopathy related to treatment with dexamethasone. Ototoxicity was seen in 3 patients. Two patients developed pulmonary emboli. Nine patients had nausea and vomiting, in one case associated with Candida esophagitis. One long-term survivor developed necrosis of the corpus callosum and dementia. Four patients discontinued treatment after an average of 3.5 cycles because of toxicity. Although extremely toxic, this regimen has modest activity in previously irradiated adult patients with malignant glioma.