Intensity-modulated radiotherapy in the treatment of breast cancer

Intensity-modulated radiotherapy (IMRT) is a newer method of radiotherapy that uses beams with multiple intensity levels for any single beam, allowing concave dose distributions and tighter margins than those possible using conventional radiotherapy. IMRT is ideal for treating complex treatment volumes and avoiding close proximity organs at risk that may be dose limiting and provides increased tumour control through an escalated dose and reduces normal tissue complications through organ at risk sparing. Given the potential advantages of IMRT and the availability of IMRT-enabled treatment planning systems and linear accelerators, IMRT has been introduced in a number of disease sites. This systematic review examined the evidence for IMRT in the treatment of breast cancer to quantify the potential benefits of this new technology and to make recommendations for radiation treatment programmes considering adopting this technique. Providing that avoidance of acute adverse effects associated with radiation is an outcome of interest, then IMRT is recommended over tangential radiotherapy after breast-conserving surgery, based on a review of six published reports including 2012 patients. There were insufficient data to recommend IMRT over standard tangential radiotherapy for reasons of oncological outcomes or late toxicity. Future research should focus on studies with longer follow-up and provide data on late toxicity and disease recurrence rates.