Radiotherapy and hyperthermia.

72 patients with either unresectable or pelvic recurrence of colorectal cancer were treated with combined radiotherapy and locoregional hyperthermia. Radiation doses were 50 Gy or more in patients not previously treated with radiotherapy, and 32 Gy (8 x 4 Gy) in patients who had previously received radiotherapy. Hyperthermia was administered within 30 min of irradiation, and the aim was to give four to six sessions once or twice a week, intending to reach temperatures of at least 41 degrees C over 30 min. The mean of all the minimum (TMIN), maximum (TMAX) and median (TMED) intratumoral temperatures were 39.6, 41.1 and 40.2 degrees C, respectively. Toxicity during hyperthermia treatment consisted mainly of local pain within the heated field (33%) and general discomfort (17%). In 17% of the patients, the hyperthermic treatment was prematurely stopped. Palliation was achieved in 75% of patients with a mean duration of 12 months. The percentage of palliated patients was higher when higher radiation doses were administered. No correlation between palliative effect and thermal parameters was found. A computed tomography scan proved objective remission was obtained in 11 patients (15%). Median survival was 11 months, and 17% of the patients were alive at 3 years. The literature on combined radiotherapy and hyperthermia in colorectal cancer is reviewed. From this review and our own data, it is concluded that thermoradiotherapy is feasible. Acute and late toxicity are not major problems, although pain and general discomfort hamper hyperthermic treatment. The most disappointing fact is that, with the available hyperthermia equipment, the increase in intratumoral temperature does not reach, in general, the therapeutic range.