Long-term results of reirradiation and hyperthermia in recurrent breast cancer

Randomized studies have shown that hyperthermia when added to reirradiation results in a higher local tumour control rate. Here we report long-term results of patients treated with reirradiation and hyperthermia in our institute since 1992. Materials and methods. 198 patients with subclinical and 250 with irresectable disease were treated, including 36 patients with tissue transfers. All patients were treated with 8 fractions of 4 Gy twice weekly, and 8 (until 1996) or 4 one-hour hyperthermia treatments applied after radiotherapy. Approximately half of the patients received radiotherapy in another institute. Hyperthermia was applied with custom built Lucite Cone Applicators operating at a frequency of 433 MHz and the whole reirradiation volume was heated. Temperatures were measured on the skin, and interstitially with fiber-optic multisensor probes within closed-tip catheters. Results In subclinical disease the 3- and 5-year local control (LC) was 83% and 78%. In patients with irresectable disease complete response was 70% and 3- and 5-year LC was 40% and 39%. 5- and 10-year overall survival was 60 and 36% for subclinical disease, and 18 and 10% for irresectable disease. Both LC and toxicity in patients with tissue transfers were similar to those in the other patients. Superficially measured temperatures > 43° were associated with more hyperthermia toxicity. The longer time interval between radiation and hyperthermia in patients irradiated elsewhere, compared to the time interval in patients irradiated in the Erasmus MC, did not result in inferior results. Patients with subclinical disease irradiated elsewhere had significantly less late grade 3-4 toxicity (7% at 5 years) than patients irradiated in the Erasmus MC (15%). Conclusions These results again show that reirradiation with hyperthermia is worthwhile. Patients with tissue transfers can be treated safely. Hyperthermia toxicity may be decreased when superficially measured temperatures are kept below 43°C.