Studies on endocrine changes induced by 8 MHz local radiofrequency hyperthermia in patients with bladder cancer

Abstract

To elucidate changes in hormone metabolism, especially thyroid, cortisol and sex hormone metabolism, during acute local heat stress, serum-free thyroxine (FT₄), free tri-iodothyronine (FT₃), reverse T₃ (rT₃), thyroxine binding globulin (TBG) and a number of other hormone levels [thyroid-simulating hormone, thyroglobulin, calcitonine, luteinizing hormone, follicle-stimulating hormone, prolactin, growth hormone, cortisol and testosterone] were measured sequentially in 11 male patients with bladder cancer during and after local radiothermotherapy treatment. Hyperthermia was administered using 8 MHz radiofrequency (RF) capacity equipment. The core temperature was raised from 37 to 42°C and maintained at 42°C for 1 h. No significant change in hormone levels except for a slight decrease in TBG levels was observed. The clinical results indicated that 8 MHz RF hyperthermia at 42°C can be applied safely as a therapeutic measure in patients with bladder tumours. Further studies concerning the changes in TBG are necessary in patients with other tumours, especially those with the complication of subclinical hyperthyroidism, to detect any corresponding rises in FT₃ and FT₄ levels. The effects of using higher temperatures also need to be examined.

Key Words:

• endocrine changes
• hormone metabolism
• thyroxine-binding globulin