New innovative techniques in radiotherapy for breast cancer.

ABSTRACT

Breast-conserving surgery (BCS) followed by adjuvant whole breast radiotherapy (WBRT) is an established treatment for early-stage breast cancer. Long-term follow-up has demonstrated equivalent survival to mastectomy. However, standard WBRT to the conserved breast requires daily radiation treatment, 5 days per week, for 5-7 weeks. This schedule imposes a considerable burden on breast cancer patients and healthcare systems alike. For the last decade, there has been considerable interest in lessening the volume of breast treated with radiotherapy and reducing the number of fractions of radiation treatment. Accelerated partial breast irradiation (APBI), including intraoperative radiotherapy (IORT), delivers high-dose radiation immediately surrounding the lumpectomy cavity, with relative sparing of the majority of the ipsilateral breast. Hypofractionated WBRT delivers radiation to the entire ipsilateral breast; however, this is achieved using a smaller number of fractions and total dose of radiotherapy. The attraction of less invasive or demanding radiotherapy schedules has led to the widespread introduction of APBI before its long-term results have been established. In the past 5 years, data from prospective trials of hypofractionated WBRT and IORT compared to standard WBRT have become available. Additionally, a large, prospective randomized study of APBI versus WBRT is nearing accrual. In this review article, we will discuss these new innovative techniques in radiotherapy for breast cancer. We will also discuss the recently completed and ongoing prospective studies that will provide a robust evaluation of the safety and efficacy of these techniques.