- Patients who have not previously undergone radiation therapy can have a history of treatment with either chemotherapy (for unresectable/borderline resectable disease) or any combination of surgery and chemotherapy (for resectable disease). Patients with no history of prior radiation treatment will constitute Cohort B and will receive SBRT as 6.6 Gy x 5. Please note that patients must have received at least two cycles of chemotherapy (with selection of drugs at the discretion of the treating oncologist) before SBRT treatment on protocol.