Conductive interstitial hyperthermia in the treatment of intracranial metastatic disease

Intracranial metastases commonly complicate oncologic care affecting 140,000 patients per year in the United States. Treatment of these tumors is difficult and often unsuccessful. Hyperthermia is a treatment alternative that has shown promise in treating cancer in other areas. Therefore it was employed in an attempt to provide increased tumor control in CNS metastases.

This Phase I and Phase II clinical trial of interstitial hyperthermia with recurrent or progressive intracranial metastatic disease was undertaken to evaluate complications, delivery of heat and patient outcome.

Feared complications of clinically significant bleeding, increased mass, or infection from the interstitial implant and treatment did not occur. The seizures which occurred in 4 patients were controlled with additional anticonvulsants. Three venous thromboembolic events were treated medically and with percutaneously placed inferior vena cava filters. The KPS of the majority of patients declined slightly with treatment but rebounded to near baseline within several months. CT scans demonstrated decrease or stabilization of tumor volumes in 7 of the 13 patients. In 4 of these patients, regression or stabilization persisted until death from nonCNS disease.

Interstitial hyperthermia therapy for intracranial metastases is technically feasible and may provide increased tumor control. In this small series, it did not cause unreasonable complications. This therapy has some positive effect, but requires study of more patients before its role is definitively known. Combining hyperthermia with brachytherapy and/or chemotherapy is being evaluated.