Pre-operative partial breast irradiation: revolutionizing radiation treatment for women with early stage breast cancer.

Partial breast irradiation (PBI) has been increasingly accepted as a suitable component of breast conservation in the management of patients with early stage breast cancer, however the majority of existing studies have focused on the use of adjuvant or intra-operative techniques. Several early stage studies have more recently shown that PBI can be safely used in the pre-operative setting. Early data show similar local control without evidence of increased toxicity or worsening cosmesis, as compared to postoperative PBI or standard whole breast irradiation. While long term data are still maturing, pre-operative accelerated PBI (PAPBI) offers a number of possible clinical advantages including reducing the treatment field and increasing the number of patients eligible for PBI, identifying biomarkers of response to radiation, and improving the rates of breast conservation and treatment compliance. This review discusses key concepts and controversies surrounding PBI as it has increasingly been adopted in the US, Canada, and Europe, and introduces the concepts and early studies of PAPBI. In addition, we summarize ongoing clinical trials investigating PAPBI, review clinical benefits and challenges associated with PAPBI versus postoperative PBI, and discuss ongoing limitations as well as next generation technologies important to the implementation of PAPBI in the management of patients with early-stage localized breast cancer.