This presentation will describe the rationale, indications and evidence for breast intensity modulated radiotherapy (IMRT) and outline different methods of delivery. Simple forward-planned IMRT can improve dose homogeneity to the whole and partial breast in cases where dose exceeds ICRU recommendations. More complex IMRT can be used in situations where a steep dose gradient is required, for example to deliver good coverage to the breast and acceptable dose to organs at risk when this cannot be achieved with tangents. It can also be used to deliver a simultaneous integrated boost and hence reduce the total number of treatment fractions.

There is phase III trial evidence showing clinical benefit for use of IMRT to improve dose homogeneity across the breast. Randomised trials are currently open which will evaluate the role of IMRT for simultaneous integrated boost compared with whole breast radiotherapy and sequential boost. The evidence for both these indications will be presented.

The various methods of breast IMRT will be outlined. More complex IMRT can produce a low dose 'bath' to normal tissue. The long term effect of this is unknown. Therefore the majority of patients should receive predominantly tangent based treatments as this is an effective method of minimising dose to adjacent organs at risk, such as the heart and lungs.

In summary, breast IMRT can vary from simple to very complex methods. It is likely that the vast majority of patients with breast cancer will benefit from some form of IMRT and all should have the opportunity to access this technology if indicated.