N. N. Sanford1, T. A. Aguilera1, M. F. Bassetti2, M. D. Chuong3, B. A. Erickson4, K. A. Goodman5, J. M. Herman6, T. S. Hong7, M. P. W. Intven8, A. Kilcoyne9, H. Kim10, A. Narang11, E. S. Paulson4, M. Reyngold12, S. Tsai13, L. Tchelebi14, R. Tuli15, E. Versteijne16, A. Wei17, J. Y. Wo7, Y. Zhang4, and W. A. Hall4; 1Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 2Department of Human Oncology, University of Wisconsin Hospitals and Clinics, Madison, WI, 3Miami Cancer Institute, Miami, FL, 4Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, 5Department of Radiation Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, 6Department of Radiation Medicine, Northwell, Lake Success, NY, 7Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 8Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands, 9Massachusetts General Hospital, Boston, MA, 10Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO, 11Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 12Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, 13Department of Surgery, Division of Surgical Oncology, Medical College of Wisconsin, Milwaukee, WI, 14Northwell, Lake Success, NY, 15USF Health Morsani College of Medicine, Tampa, FL, 16Department of Radiation Oncology, Amsterdam University Medical Center, Amsterdam, Netherlands, 17Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY
Purpose/Objective(s): Dose-escalated radiotherapy is increasingly used in the treatment of pancreatic cancer, however approaches to target delineation vary widely. We present the first North American cooperative group consensus contouring atlas for dose-escalated pancreatic cancer radiotherapy. Materials/
Methods: NRG Oncology recruited an expert international panel comprising 17 radiation oncologists, 2 surgeons and 1 radiologist. Participants used software to contour high and low risk clinical target volumes (CTV) on three representative cases: a borderline resectable head tumor, a locally advanced head tumor, and a tail tumor. Simultaneous truth and performance level estimation (STAPLE) volumes were created, representing probabilistic weighted global aggregated results. Contours were analyzed using DICE3D similarity coefficients and mean/max distance against STAPLE volumes, and guidelines were reviewed with the entire multidisciplinary panel. Results: 15 radiation oncologists contoured a total of 45 volumes. The gross tumor volume (GTV) for the borderline head, locally advanced head, and tail tumor cases were 156.7 cc, 58.2 cc and 9.0 cc, respectively. The high and low risk STAPLE CTVs were 355.7 cc/591.5 cc, 141.5 cc/267.9 cc, and 32.4 cc/182.6 cc, and the DICE3D similarity coefficients (SD) were 0.80(0.06)/0.79(0.11), 0.82(0.07)/0.78(0.10), and 0.74(0.14)/0.45(0.17), respectively. The mean and max distance from STAPLE volume for the high-risk CTV for the 3 cases was 4.2 mm/12.0 mm, 3.3 mm/7.8 mm and 2.7 mm/6.5 mm and for the low-risk CTV were 5.4 mm/14.7 mm, 4.8 mm/11.2 mm and 15.9 mm/51.1 mm. Consensus volumes were agreed upon. High-risk CTVs comprised the tumor plus abutting vessel (celiac and branches, superior mesenteric, splenic, and portal). The low-risk CTV covered areas of perineural and perivascular spread, starting superiorly at (tail) or 1 cm above (head) the celiac takeoff and extended inferiorly to the superior mesenteric artery (SMA) at the level of the first jejunal takeoff. For head tumors, the lateral volume encompassed 1 cm around the celiac, SMA, superior mesenteric vein (SMV) and included the common hepatic artery and medial portal vein. For tail tumors, the body and tail of the pancreas were included, along with the splenic vessels and the takeoffs of celiac and SMA. Detailed dose prescription and normal organ constraints will be provided at time of presentation. Conclusion: Through multidisciplinary and international collaboration from pancreatic cancer experts, we created consensus contouring guidelines for dose-escalated pancreatic cancer radiotherapy, reflecting current knowledge of recurrence patterns, and considering novel treatment techniques. These volumes can be used to standardize practice across clinical settings and in prospective trials seeking to define the role of radiotherapy in pancreas cancer.
