Introduction

This special issue of International Journal of Hyperthermia highlights the role of hyperthermia in the treatment of breast cancer. The first documented use of thermal therapy for breast cancer was more than 5,000 years ago, as chronicled in the Edwin Smith Papyrus [1]. In this ancient Egyptian document, the history of breast cancer treatment begins with cauterisation of tumours found in the breast with an instrument known as ‘the fire drill’.

In modern times, clinical trials demonstrate improved outcomes with the addition of hyperthermia to radiation therapy and chemotherapy. We start this issue with two comprehensive overviews of the literature for radiation and superficial hyperthermia in chest wall recurrence, and in combination with radiation and chemotherapy for locally advanced breast cancer. Another paper discusses the role of MR imaging for the response assessment in locally advanced breast cancer patients receiving hyperthermia. An update from the Erasmus Medical Centre in the Netherlands, one of Europe's largest hyperthermia centres, completes the set of papers on clinical hyperthermia.

Considerable progress in the laboratory has led to better understanding of the biology of breast cancer and implications for individualised therapy and refinement of prognostic factors. Advances in hyperthermia biology have also led to refinements for individualised thermochemotherapy approaches and prognostic factors. The ubiquitous heat shock protein family also offers an interesting avenue to exploiting hyperthermia biology, as in their role as cancer vaccine adjuvants, and perhaps even an emerging family of anticancer agents exploiting small molecule inhibitors of heat shock proteins.

The technology for hyperthermia delivery and real time monitoring of thermal dose has undergone considerable progress. New conformal microwave array applicator designs and updates on simultaneous superficial thermoradiotherapy of breast cancer are reviewed in detail. Methods for improving conformal heating by adaptively refining calculations may also improve dose delivery. New opportunities in the refinement of absolute temperature imaging are described using intermolecular multiple quantum MRI.

The breadth of contributions from the authors in this special issue highlights the tremendous progress that has occurred in the role of hyperthermia for the treatment of breast cancer. This has garnered broad interest at the national level, and the impact of this work led the National Comprehensive Cancer Network (NCCN) to include hyperthermia in the 2007 Breast Cancer Guidelines for recurrent breast cancer [2].

In summary, there is a strong biological rationale for the use of hyperthermia in breast cancer, and this has been proven in clinical trials to enhance treatment outcome. Further technological advances in applicator design and thermometry may also enhance clinical development.