Patients with high-grade primary and metastatic brain malignancies have a median survival time of 3-8 months, regardless of therapy. Because MagnetrodeTM hyperthermia provides safe, deep internal heating without normal-tissue injury, we studied its effects first on the brain and surrounding tissues of rabbits. The normal rabbit brain (n = 26) could be heated to potentially tumoricidal temperatures (42-43 degrees C) without apparent histopathologic or clinical damage to the brain, skull, external eye, subcutaneous tissue or skin. Intracranial pressure did not rise significantly. Using transplanted VX-2 carcinoma, we showed both the safety and potential efficacy of thermochemotherapy (IV BCNU: 14 mg/kg) in the presence of a solid brain tumor. The average maximum brain temperature achieved was 43.06 degrees C. Mean survival from the time of tumor implantation in the treated group (n = 16) was 18.56 days, compared to 9.3 days for untreated controls (n = 30) (p less than .0001). Two patients have been treated with localized brain hyperthermia combined with intravenous BCNU (80 mg/m2) for a total of eight treatments. Maximum normal brain temperature achieved was 40.0 degrees C in Patient #1 and 41.5 degrees C in Patient #2. A tumor temperature of 42.9 degrees C was achieved in Patient #2. Intracranial pressure remained within the upper limits of normal. Swan-Ganz monitoring in Patient #1 revealed a stable cardiac index and mean pulmonary artery pressure with mild fluctuations in the CVP, PAD, and PCW. No increase in chemotherapy toxicity was observed and no normal tissue injury occurred in either patient. We conclude that non-invasive localized radiofrequency hyperthermia to the brain is feasible and can be performed safely in the presence of a solid brain tumor.

Retroperitoneal sarcomas are a varied group of malignancies which have a high rate of recurrence following surgery alone. The majority of the initial recurrences are local in nature, and new therapeutic approaches are clearly needed. Diagnostic imaging and "interventional radiology" have important roles to play in the management of these malignancies, as well as in investigational approaches to therapy. Two cases are presented which illustrate some recent advances in diagnosis and staging of this group of tumors which can be attributed to new cross-sectional imaging techniques, when used in concert with "conventional" imaging methods. The latter include arteriography to guide the placement of intra-arterial catheters for local infusion chemotherapy. CT-guided needle biopsies can be performed to secure a preoperative diagnosis and also to obtain viable tissue for in vitro chemosensitivity assays. A judicious combination of local and systemic chemotherapy, radiation, and surgery may hold promise for better control of this malignancy, similar to the therapeutic advances which have already been obtained with limb sarcomas.

High-grade primary and refractory brain tumors and metastases to the brain from other primary sites are associated with a grave prognosis. Treatment, usually palliative, consists of some combination of surgery, radiation, and chemotherapy. Recently, noninvasive hyperthermia by magnetic-loop induction has been safely used to treat patients with advanced cancer in extracranial sites. Both disease regression and disease stabilization have been observed. This technique was recently applied to brain tumors in an animal model, and its safety was again demonstrated. As a result, a Phase I trial of noninvasive localized hyperthermia in combination with intravenous chemotherapy has been carried out in ten patients whose primary or metastatic brain tumors failed to respond to standard therapy. Ten patients underwent 23 thermochemotherapy sessions using the magnetic-loop induction device. The median, maximum temperature of normal brain after 1 hour of hyperthermia was 41.1 degrees C (range, 38.6 degrees C-43.4 degrees C); the median, maximum temperature of brain tumor was 42.5 degrees C (range, 38.8 degrees C-46.3 degrees C) (P less than 0.01). The temperatures of both the normal brain and brain tumor were obtained during 18 treatments. The tumor temperature was greater than the normal brain temperature in 15 of 18 treatments. In 78% of the treatments, the measured tumor temperature reached at least 42 degrees C, whereas the normal brain reached 42 degrees C in only 13% of the treatments. These data demonstrate the "selective inability" of brain tumor tissue to dissipate heat. Vital signs, intracranial pressure, and neurologic status were monitored throughout the hyperthermia treatments. No mortality or increase in chemotherapeutic toxicity could be attributed to the thermochemotherapy. In addition, there were no local complications or permanent neurologic complications. Two patients with elevated intracranial pressure before therapy had transient neurologic deficits that may have been exacerbated by the hyperthermia. It is concluded that this new, noninvasive modality not only produced effective intracranial tumor heating, but could be performed safely with the proper precautions. Phase II trials are warranted.

Normal brain and brain tumor temperatures were studied for their effects on intracranial pressure (ICP) in 13 patients who received 37 localized thermochemotherapy treatments for recurrent primary or metastatic brain tumors. Two transient neurologic complications occurred in patients with an elevated initial ICP value; thus, the authors concluded that an initial ICP value of 30 cm H2O or greater may contraindicate brain hyperthermia. It appears that noninvasive brain hyperthermia by magnetic-loop induction can cause an initial rise in ICP value, although a protective mechanism(s) that tends to lower ICP occurs over time, and also at a normal brain temperature of approximately 42.0 degrees C. Possible mechanisms of ICP reduction include direct heating of the hypothalamus with a reduction in pCO2 and the development of tachypnea and hyperpnea with a reduction in pCO2. Hyperthermia applied to the brain should be undertaken only with adequate monitoring of ICP; in addition, extreme caution should be taken in patients with an elevated initial ICP value and in those patients in whom adaptation to elevated pressure does not occur.

In a test of electromagnetic induction hyperthermia to deep viscera of a live dog model, we found that heating was not uniform to any depth, but was quite variable. In general, there was a thermal gradient between peripheral and central portions of the transposed spleen of about 1 degree C. Though heat generation within the abdomen was not uniform, its temperature pattern in the alive animal resulted in significant heating of that part of the organ that had been surgically placed at the center of the animal. This heating could not be explained by perfusion with regionally heated core blood. Our results indicate that extensive investigations in living systems and complex dynamic phantoms will be necessary before individual patient response can be predicted.