Reirradiation combined with hyperthermia in breast cancer recurrences: overview of experience in Erasmus MC.

For superficial hyperthermia a custom-built multi-applicator multi-amplifier superficial hyperthermia system operating at 433 MHz is utilised. Up to 6 Lucite Cone applicators can be used simultaneously to treat an area of 600 cm2. Temperatures are measured continuously with fibre optic multi-sensor probes. For patients with non-standard clinical problems, hyperthermia treatment planning is used to support decision making with regard to treatment strategy. In 74% of our patients with recurrent breast cancer treated with a reirradiation scheme of 8 fractions of 4 Gy in 4 weeks, combined with 4 or 8 hyperthermia treatments, a complete response is achieved, approximately twice as high as the CR rate following the same reirradation alone. The CR rate in tumours smaller than 30 mm is 80-90%, for larger tumours it is 65%. Hyperthermia appears beneficial for patients with microscopic residual tumour as well. To achieve high CR rates it is important to heat the whole radiotherapy field, and to use an adequate heating technique.