This trial is open to newly diagnosed Stage I-III breast cancer patients with an indication for post-operative radiotherapy after neo-adjuvant chemotherapy and surgery.

Patients undergoing primary systemic therapy, followed by surgery often receive post-operative radiation. While the targets treated post-operatively vary and depend on the initial and post-surgical stage, patients generally undergo 6-7 weeks of daily (Monday to Friday) post-operative radiation.

This approach is long and draining, particular in this population of breast cancer patients often experiencing chemotherapy induced fatigue. Our group has developed and tested a combined positioning and hypo-fractionated regimen of post-operative radiotherapy that may be particularly convenient and indicated for these women.

Specifically a prone set-up has enabled safe sparing of heart and lung while targeting the breast and, more recently, level III and supraclavicular nodes.

While we have extensively tested this approach in the classical adjuvant setting of breast cancer, until now we have not tested it after neo-adjuvant chemotherapy.

We are proposing a prospective study to test feasibility of probe breast and nodal radiotherapy in women who have undergone surgery after preoperative systemic therapy.

The study has two cohorts, Cohort 1 (Radiation to the Breast and Chest Wall) and Cohort 2 (Radiation to the Breast and Chest Wall and to the Level III/Supraclavicular Nodes).