Regional hyperthermia: A feasibility analysis

Thirty patients received regional hyperthermia using the annular phased array system (APAS) in conjunction with either radiotherapy or chemotherapy. A total of 139 treatment sessions were available for analysis, averaging 4.6 per patient. The number of hyperthermia sessions per patient varied from 1 to 9 and was dependent on the patients' tolerance. The duration of the sessions also varied considerably. Although the goal of each session was to attain temperatures of 42°C or higher for 1 h, minimally one-half hour, this was rarely achieved. Temperatures of 42°C or higher were achieved in 95 (68.8 per cent) sessions. The time span at that level ranged between 1 and 40 min, median 8.5 min. The predominant limiting factor in 18 (60 per cent) of patients was local discomfort. Generalized discomfort (anxiety) was a predominant limiting factor in 5 (16.6 per cent), systemic temperature elevation in 3 (10 per cent), and tachycardia in two (6.6 per cent) patients. Careful attention to technical details and patient preparation may ameliorate or eliminate some of the limiting factors and improve the efficacy of heat delivery.