Clinical experience using 8 MHZ radiofrequency capacitive hyperthermia in combination with radiotherapy : results of a phase I/II study

• Published in: International journal of radiation oncology, biology, physics Vol. 32; no. 3; pp. 733 - 745
• Main Authors: LEE, C. K, SONG, C. W, RHEE, J. G, FOY, J. A, LEVITT, S. H
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier 15.06.1995
• Subjects: Adenocarcinoma - mortality; Adenocarcinoma - pathology; Adenocarcinoma - radiotherapy; Adenocarcinoma - therapy; Adult; Aged; Aged, 80 and over; Biological and medical sciences; Carcinoma, Squamous Cell - mortality; Carcinoma, Squamous Cell - pathology; Carcinoma, Squamous Cell - radiotherapy; Carcinoma, Squamous Cell - therapy; Combined Modality Therapy; Combined treatment; Female; Follow-Up Studies; Head and Neck Neoplasms - mortality; Head and Neck Neoplasms - pathology; Head and Neck Neoplasms - radiotherapy; Head and Neck Neoplasms - therapy; Hot Temperature; Humans; Hyperthermia, Induced - adverse effects; Hyperthermia, Induced - methods; Male; Medical sciences; Medicin och hälsovetenskap; Middle Aged; Pelvic Neoplasms - mortality; Pelvic Neoplasms - pathology; Pelvic Neoplasms - radiotherapy; Pelvic Neoplasms - therapy; Remission Induction; Survival Analysis; Treatment. General aspects; Tumors; Human; Cancerology; Treatment efficiency; Phase II trial; Instrumentation therapy; Phase I trial; Combined treatment; Safety; Radiofrequency; Radiotherapy; Induced hyperthermia
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/0360-3016(94)00608-N

Since 1985, the University of Minnesota Hospital and Clinic has investigated the efficacy and safety of 8 MHz radiofrequency (RF) capacitive hyperthermia using the Thermotron RF-8. This study reports the thermometric and clinical results of 119 patients treated with RF hyperthermia in combination with radiotherapy (RT). Of 119 patients, 69 received high-dose RT and 50 patients received low-dose RT because of previous irradiation to the treatment site. The most common anatomic sites treated were within the pelvic cavity or head and neck area. Thirty-three percent and 24% of tumors treated were > 7 cm and > 10 cm in largest diameter, respectively. Forty percent of the patients had deep-seated tumors (depth > 6 cm). Hyperthermia was given as soon as possible after RT twice weekly, allowing at least 72 h between treatments. The objective was to raise intratumoral temperatures to 42-43 degrees C or above for 30-50 min while keeping normal tissue temperatures below 40-41 degrees C. Of 119 patients, 40% achieved a Tmax tumor temperature of > 42 degrees C and 40% achieved 40-42 degrees C Tmax. Higher Tmax) tumor temperatures were observed as tumor size increased. Tumors > 10 cm in largest diameter had a Tmax of 42.2 degrees C. Tumor depth was not a significant factor for the tumor temperatures achieved. Of 119 patients, 11% achieved complete response and 38% achieved partial response. Of the no-response patients, 34% had symptomatic palliation and 15% had stable disease for at least 12 months after treatment. We were able to treat tumors of patients with subcutaneous fat as thick as 3 cm by precooling the fat for 20 min with 10-15 degrees C saline-filled boluses prior to the initiation of heating. During treatment, 60% of patients complained of varying degrees of pain and 19% had pain that was a factor in limiting treatment. Vital signs were relatively stable and not a factor in limiting treatment. The Thermotron RF-8 is a useful hyperthermia device that can raise tumor temperatures to a therapeutic level (i.e., 42 degrees C) in a significant proportion of patients with superficial, subsurface, and deep-seated tumors, with minimal adverse effects, complications, and systemic stress. Further clinical studies using improved thermometry systems are warranted.