REGIONAL HYPERTHERMIA OF PELVIC TUMORS USING THE UTRECHT COAXIAL-TEM SYSTEM - A FEASIBILITY STUDY

Between August 1989 and July 1992 a total of 22 patients (64 treatment s) with inoperable or recurrent deep seated pelvic tumours were treate d with regional hyperthermia and radiotherapy. The 70 Mhz Coaxial TEM applicator with its characteristic open waterbolus was used as heating device. The main objective of this pilot study was to evaluate the fe asibility, toxicity and temperature data. The results showed that the major treatment limiting factors were insufficient power and systemic stress. Local pain was observed in only 10% of all treatments. Most of the treatments resulted in elevated systemic temperatures with the ov erall mean maximum oesophagus temperature reaching 38.9 +/- 0.7 degree s C, however, in only 6% of these treatments this was found to be trea tment limiting. From the measured data the following intratumoral temp eratures were calculated: T-90 = 39.9 +/- 1.0 degrees C; T-50 = 40.7 /- 1.0 degrees C; T-10 = 41.4 +/- 1.00C. In addition, the overall mean average normal tissue temperatures were determined: T-rectum = 40.8 /- 0.7 degrees C; T-vagina = 41.3 +/- 0.9 degrees C; T-urethra = 40.8 +/- 0.9 degrees C. The temperatures in normal tissue were frequently h igher than in tumour, indicating that a large volume was heated. The o pen waterbolus allows strong cooling, but the strategy was changed dur ing the study: higher systemic temperatures were allowed to improve th e pelvic temperatures. This pilot study proved that the open waterbolu s is clinically a success, because it offers patient comfort and SAR-s teering by patient repositioning, and that regional hyperthermia with the Coaxial TEM is feasible.