Preoperative stereotactic breast radiation may be beneficial as it offers the ability to target smaller treatment volumes than what has been achievable with adjuvant PBI (Nichols IJROBP 2010), track radiobiological response to radiation at time of surgical pathology, and allow the removal of all irradiated tissue to potentially minimize late effects.The purpose of this phase I trial is to evaluate dose-limiting toxicity while dose escalating single-fraction preoperative S-PBI to a presumed radioablative dose over 3 cohorts, starting with 30Gy in 1 fraction and advancing to 34Gy and 38Gy in 1 fraction. This would be accomplished on the CyberKnife or GammaPod. The GammaPod is a novel device dedicated to S-PBI utilizing a Cobalt-60 source (Yu Med Phys 2013), which offers a highly reproducible prone setup with a mean of 1.8mm of mismatch reported in 15 patients at the University of Maryland on consecutive scans (Yu JCO 2011). Implications of this research are far reaching, including determination of the maximally tolerated dose for preoperative S-PBI, pathologic complete response rates of early stage breast cancer to a predicted radioablative dose, radiographic markers of treatment response (radiomics), and translational research assessing mechanisms of immune and radiation response.
The purpose of this phase I trial is to evaluate dose-limiting toxicity while dose escalating single-fraction preoperative S-PBI to a presumed radioablative dose over 3 cohorts, starting with 30Gy in 1 fraction and advancing to 34Gy and 38Gy in 1 fraction.