Clinical experience using 8 MHz radiofrequency capacitive XXXX in combination with radiotherapy: results of a phase I/II study.

@entity1 @entity221 @entity5 @entity158
PURPOSE: Since 1985, the University of Minnesota Hospital and Clinic has investigated the efficacy and safety of 8 MHz radiofrequency (RF) capacitive @entity221 using the Thermotron RF-8. This study reports the thermometric and clinical results of 119 @entity1 treated with RF @entity221 in combination with radiotherapy (RT). METHODS AND MATERIALS: Of 119 @entity1 , 69 received high-dose RT and 50 @entity1 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 @entity5 treated were > 7 cm and > 10 cm in largest diameter, respectively. Forty percent of the @entity1 had @entity5 (depth > 6 cm). @entity221 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. RESULTS: Of 119 @entity1 , 40% achieved a Tmax @entity5 temperature of > 42 degrees C and 40% achieved 40-42 degrees C Tmax. Higher Tmax) @entity5 temperatures were observed as @entity5 size increased. Tumors > 10 cm in largest diameter had a Tmax of 42.2 degrees C. @entity5 depth was not a significant factor for the @entity5 temperatures achieved. Of 119 @entity1 , 11% achieved complete response and 38% achieved partial response. Of the no-response @entity1 , 34% had symptomatic palliation and 15% had stable disease for at least 12 months after treatment. We were able to treat @entity5 of @entity1 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 @entity1 complained of varying degrees of @entity158 and 19% had @entity158 that was a factor in limiting treatment. Vital signs were relatively stable and not a factor in limiting treatment. CONCLUSION: The Thermotron RF-8 is a useful @entity221 device that can raise @entity5 temperatures to a therapeutic level (i.e., 42 degrees C) in a significant proportion of @entity1 with superficial, subsurface, and @entity5 , with minimal adverse effects, complications, and systemic stress. Further clinical studies using improved thermometry systems are warranted.
