Robert W. Paglione

Microwave applicators for localized hyperthermia treatment of cancer of the prostate

Abstract Directional coaxial applicators designed for operation with microwave frequencies of 915 MHz or 2450 MHz are described. Hyperthermia can be induced in tumors located within, or in the vicinity of, natural body cavities by means of these applicators. This paper reports on a method developed in animal experiments for the use of these applicators as therapeutic tools and on results of initial clinical trials using this technique in cases of cancer of the prostate.

Microwave Hyperthermia for Brain Tumors

Twelve patients with malignant brain tumors who had failed to respond to conventional therapies were treated with thermotherapy. Hyperthermic temperatures (approximately 43 degrees C) were induced in the tumors using microwaves at a frequency of 2450 MHz that were guided into the tumors by one or more semirigid coaxial applicators. These applicators fit into 16 gauge tubes or needles and can be inserted into the brain with minimal damage to healthy tissues. During each treatment, the tumors were maintained at hyperthermic temperatures for 1 hour. Several treatments spaced a few days apart were usually administered. The procedure used for producing hyperthermia in brain tumors with microwaves proved to be safe and could be repeated several times without producing toxic effects. Objective tumor responses were obtained in 75% of the patients (decrease in tumor size, 3 patients; slowing of tumor growth, 2 patients; necrosis of tumor tissues verified by pathological examination, 4 patients). Favorable clinical responses were observed in 75% of the patients (rapid decrease in intractable headaches, 5 patients; improvements in clinical deficits, 4 patients). Also, in all patients, the microwave power required to heat for a given time or a given volume decreased during most of the thermotherapy sessions, possibly because of heat damage to the tumor vasculature. Our results, taken together with the results of other investigators, indicate that thermotherapy is a promising modality for treating malignant brain tumors, either as the sole therapy or in combination with radiotherapy and chemotherapy. The next logical steps would be Phase I/II type trials of subjects whose disease is less advanced than the disease of patients treated in the current series of investigations.

Microwave-induced hyperthermia in cancer treatment: apparatus and preliminary results.

Abstract Apparatus for the controlled local heating of cutaneous and subcutaneous tumors is described. This apparatus, which uses microwave radiation in the frequency 915 MHz or 2450 MHz, can raise the temperature of such tumors to the hyperthermic range (42.5–43°C), i.e. the temperature range which appears to be optimum for the treatment of malignant tumors. Encouraging results have been obtained with this apparatus in treating malignancies in laboratory animals and in man. Complete eradication of transplanted mammary adenocarcinoma was achieved in C3H mice. In several clinical cases, hyperthermis appeared to be beneficial in the treatment of basal. cell carcinoma, malignant melanoma, and skin metastases of carcinoma of the breast.

Some Practical Considerations for the Use of Localized Hyperthermia in the Treatment if Cancer

AbstractPractical considerations in the selection and administration of microwave and RF induced hyperthermia in the treatment of various tumors are discussed. A thorough knowledge of the thermal properties of the tumor and its environment is required for the establishment of an effective therapeutic regimen. Examples of clinical observations illustrate the patients’ general tolerance to the therapy and highlight the problems presented by some special cases. Possible ways of avoiding adverse effects during localized microwave induced heating of superficial tumors and RF heating of deep seated tumors are described.

Microwave hyperthermia radiosensitized iridium — 192 for recurrent brain malignancy

Twenty-one patients whose solitary detectable biopsy proven recurrent brain malignancies produced Central Nervous System (CNS) symptoms warranting further intervention received 60-minute 43 degrees C (180 degree-minute) interstitial 2450 MHz microwave hyperthermia fractions. All received brain teletherapy prior to recurrence. The first 15 received no brachytherapy and served as a toxicity pilot. All 15 enjoyed neurologic improvement, 12 symptomatic improvement, and 12 objective response as mass reduction and/or tumor necrosis. The next 6 patients were selected with more favorable Karnofsky performance status, no known active malignancy elsewhere, and received afterloading Ir-192 interstitial implantation juxtaposed to radiosensitizing hyperthermia. Volume dose varied from 1000 to 2245 rad, and dose rate from 40 to 100 rad/hr. Dose selected varied as a function of pre-recurrence teletherapy dose, general condition, histologic type, and volume. Neurosurgical debulking, if technically indicated through no additional aperture or trauma, was permitted if consistent with preservation of neurological function. Six enjoyed neurologic improvement, symptom reduction, and objective tumor response; three remain alive, and one experienced transient improvement. Complications, histologic subtypes, autopsy findings, stereotactic approach, thermal monitoring methods and CT follow-up of objective response are presented along with computer dosimetry and isotherm chart. Our microtraumatic universal catheter technique for CT guided stereotactic biopsy, aspiration, decompression, thermal sensory loop, thermalization antennae, and brachytherapy without multiple trauma nor changing catheters is stressed. The rationale for combined modes peculiar to the CNS will be outlined.2+ Proposal for incorporating controlled-release ARA-C chemotherapy polymer micro-rods into the interstitial format will be offered. The preceeding is an FDA-approved controlled clinical trial.(ABSTRACT TRUNCATED AT 250 WORDS)