As the key question is whether the sequencing of the aromatase inhibitor anastrozole alters local control by acting as an enhancer of the radiation breast cancer cell kill, it is therefore the aim of this study to compare 3 months of anastrozole prior to radiotherapy versus 3 months of anastrozole after radiotherapy with a specific objective of reducing the baseline ratio of in- field radiotherapy failure from 6% to 3%.This pilot study is preliminary to a planned long term study to investigate local failure.