Hyperthermic therapy for human neoplasms: thermal death time

Area of Science:

• Oncology
• Biophysics
• Medical Technology

Background:

• Hyperthermia above 42°C is tumoricidal, but effective deep heating technology was lacking.
• Previous research on human cancer thermal death times was limited due to technological constraints.

Purpose of the Study:

• To test the hypothesis that hyperthermia temperature and duration are critical for tumor necrosis.
• To evaluate a new radio frequency device for safe and effective deep hyperthermia delivery.

Main Methods:

• Utilized a novel radio frequency device for uniform deep hyperthermia in 38 advanced cancer patients.
• Measured temperatures in tumors and normal tissues, heating tumors between 40°C and ≥50°C for 13-600 minutes.
• Assessed tumor necrosis via serial biopsies, comparing outcomes across different temperatures and treatment durations.

Main Results:

• 70% of tumors reached ≥42°C, 52% reached ≥45°C, and 32% reached ≥50°C, with no significant normal tissue injury.
• Single hyperthermia sessions at ≥50°C caused 20-100% tumor necrosis; lower temperatures were ineffective.
• Multiple treatments at 45-50°C yielded 70-100% necrosis, demonstrating temperature and duration's impact.

Conclusions:

• Clinical results support the link between hyperthermia temperature, duration, and tumor necrosis.
• Higher temperatures and longer treatment times are most effective for inducing cancer cell death.