SBRT for Close or Positive Margins After Resection of Pancreatic Adenocarcinoma

Radiation simulation will be done in Shadyside Radiation Oncology department Contrast-enhanced CT based simulation will be obtained prior to any adjuvant treatment (2-4 weeks post-op depending on healing). The target volume will be identified based on fiducial marker placement at time of surgery as well as a detailed discussion and image review with the operating surgeon. This are will be contoured on axial CT images obtained at 1.25 mm slice thickness. These volumes will then be reconstructed into a 3-dimensional image set for SBRT planning. Subjects will be simulated in the treatment position (supine with arms raised) on the CT scanner table the appropriate immobilization. Optiray® contrast will be administered intravenously at a flow rate of 2.5 mL/s. A helical CT scan of the abdomen will be acquired with intravenous contrast starting 30 seconds prior to CT acquisition. A 4D CT data acquisition for the same axial extent will be obtained. The images will then be electronically transferred from the CT workstation via DICOM3 to the appropriate treatment planning workstation in the department of radiation oncology. Based on axial CT images, fiducial marker placement, review of the pathology report, and a detailed discussion with the operating surgeon, contours will be drawn of the clinical target volume (CTV), which is defined as the area at risk for microscopic disease. The planning target volume (PTV) will be equivalent to the CTV unless motion is detected on the 4D motion study. If there is motion, the amount of motion in the superior-inferior, lateral, and anterior-posterior directions will be the margin given. Surrounding normal and critical structures will also be contoured by the treating radiation oncologist including the kidneys, liver, small bowel, spinal cord, and stomach if necessary. Stereotactic Body Radiotherapy Planning An SBRT plan will be created by a medical physicist based on the PTV contoured on the CT scan. The plan will be to deliver fractionated SBRT to the isodose line best encompassing the PTV. Careful evaluation of each plan will be conducted by the radiosurgical team to ensure that normal tissues and critical structures tolerances are maintained. The maximum dose (in Gy) within the treatment volume (MD), prescriptions dose (PD), and the ratio of MD/PD (as a measure of heterogeneity within the target volume), prescription isodose volume (PIV in mm3), tumor volume (TV in mm3), and the ratio of PIV/TV (as a measure of dose conformity of the treatment relative to the target) will be recorded. Evaluation during treatment The subjects will be carefully followed while on active treatment and post-treatment for 24 months, or until death. Treatment following SBRT All patients will have been seen in a multi-disciplinary pancreatic cancer clinic. As such, they will be set up with a medical oncologist. Following completion of SBRT as described in this protocol, the patient's medical oncologist may, at his/her discretion, administer systemic therapy according to the current standard of care or the UPMC pathways.