Partial Breast Re-irradiation for Breast Cancer

The therapeutic challenge in re-irradiation involves finding a balance between tumor control and the risk of severe toxicity from cumulative radiation doses in previously irradiated organs. Re-RT options include the use of brachytherapy (BT) \], intraoperative radiotherapy (IORT) or external beam RT with photons or electrons. Depending on the time interval since previous RT and applied technique, high-grade (≥3) toxicity rates for re-RT range from about 9% acute skin to 12 % - 17 % late fibrosis and 1% - 10 % G4 toxicity for BT, late grade 3 fibrosis of 21% for IORT and grade 3 toxicity (skin, esophagitis, wound dehiscence) of 7 - 24% - 35% for EBRT including late breast volume asymmetry in 12%, acute and late grade 4 ulceration (1-2%) and even grade 5 (treatment related deaths) in 1.2%. The dosimetric profile of PBT with the Bragg Peak offers advantageous physical properties and has proven to be superior to photon-based techniques in respect of dose reduction to adjacent organs-at-risk (OAR) and effective target volume coverage with lower integral doses to the patient's whole body. In addition, this technique could potentially offer higher radiobiological effects and tumor responses \[28\], which is particularly advantageous in potentially more therapeutically resistant disease biology in breast cancer recurrences. Overall, prospective experience related to re-RT of the ipsilateral breast after recurrences is limited and most commonly involves the technique of invasive multicatheter brachytherapy.