A phase II trial to evaluate single-dose stereotactic body radiation therapy (SBRT) prior to surgery for early-stage breast carcinoma: SIGNAL (stereotactic image-guided neoadjuvant ablative radiation then lumpectomy) trial

AbstractBackgroundBreast-conserving therapy has become a preferred option in the treatment of early breast cancer. Current breast-conserving therapy includes 3–5 weeks of external beam radiotherapy to the whole breast, sometimes followed by a 1–2-week boost to the tumor bed. However, the duration of the radiation regimen can be prohibitive for the elderly, infirm or immobile patients, those patients who live far from the cancer center, or those who have difficulty taking an extended leave of absence. We propose to treat these patients with a single dose of radiation preoperatively, thereby shortening the total treatment time.MethodsThis is a single-arm phase II case series trial, conducted on 120 patients with early breast cancer who will be accrued from multidisciplinary breast cancer clinics. These patients will have research biopsies taken at the time of enrollment and will undergo radiation planning with CT simulation and PET/MRI. A single dose of 21 Gy will then be delivered in the prone position to the tumor. A second research biopsy will be taken, then lumpectomy will be performed. This entire procedure will be completed within 1 week (7 days). The primary endpoint is rate of toxicity (≥grade 2 fibrosis), and secondary endpoints include cosmetic results, quality of life, and rate of recurrence.DiscussionThis study will assess the toxicity associated with using a single preoperative dose of radiation as a replacement for standard adjuvant radiotherapy in breast-conserving therapy. Results of this trial will guide the design of a possible phase III study. Trial registration: Clinicaltrials.gov identifier: NCT02212860