1101 - Consensus Organ at Risk (OAR) Constraints for Radiotherapy (RT) for Hematologic Malignancies for NCTN Trials
Presenter(s)
A. J. Sim1, B. S. Hoppe2, L. K. Ballas3, S. A. Milgrom4, S. A. Terezakis5, C. S. Ha6, N. B. Figura7, R. R. Parikh8, J. C. Grecula9, J. P. Plastaras10, A. C. Lo11, J. Ryckman12, S. Flampouri13, C. C. Pinnix14, and C. R. Kelsey15; 1Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, OH, 2Mayo Clinic, Jacksonville, FL, 3Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, 4University of Colorado, Department of Radiation Oncology, Aurora, CO, 5University of Minnesota: Department of Radiation Oncology, Minneapolis, MN, 6University of Texas Health Science Center at San Antonio, San Antonio, TX, 7H. Lee Moffitt Cancer Center and Research Institute, Department of Radiation Oncology, Tampa, FL, 8Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 9Department of Radiation Oncology, James Cancer Hospital/Wexner Medical Center, The Ohio State University, Columbus, OH, 10Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, PA, 11Division of Radiation Oncology, Department of Surgery, University of British Columbia, Vancouver, BC, Canada, 12University of West Virginia, Charleston, WV, 13Emory School of Medicine, Atlanta, GA, 14Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 15Duke University Medical Center, Department of Radiation Oncology, Durham, NC
Purpose/Objective(s): Modern RT allows for improved sparing of OARs, decreasing toxicity risks. Prospective trials in the National Clinical Trials Network (NCTN) incorporate RT dose constraints based on solid malignancies. As patients with hematologic malignancies are often younger with more favorable prognoses and treated with lower RT doses, customized constraints for hematologic NCTN trials are needed.
Materials/Methods: A review of OAR constraints from published primary literature, the NRG Center for Innovation in Radiation Oncology (CIRO), and US national guidelines was commissioned by the NRG Oncology Hematologic Working Group and customized by iterative review. Final recommendations were approved by radiation oncology representatives from lymphoma committees of NCTN groups (NRG, COG, Alliance, ECOG-ACRIN, SWOG, CCTG).
Results: For 45 OARs, a strict recommended constraint was determined, 18 of which were not present in CIRO. Of the remaining 27 OARs, 17 were lower, 2 were the same, and 5 used different metrics than in CIRO; 3 were higher than at least one CIRO trial constraint. To allow for flexibility, acceptable variations were determined. Unacceptable variations were added for select critical OARs for plan scoring. While doses to OARs without explicit unacceptable variations should not exceed acceptable variations, violations should not be considered for plan quality assessment on trials. Representative OARs are provided (Table).
Conclusion: RO representatives from 6 NTCN lymphoma committees developed consensus recommended OAR constraints for future NCTN trials incorporating RT for hematologic malignancies. Strict dose constraints will minimize toxicities in this patient population.
Support: U10 CA180868, U10 CA180821,U10 CA180820, U10 CA180899, U10 CA180888, U10 CA180819, U10 CA180886, U10 CA180863, CCS 707213; https://acknowledgments.alliancefound.org Abstract 1101 - Table 1: Select constraints (standard fractionation)| OAR | Solid Tumor Constraints | Hematologic Malignancy Constraints | Toxicity | ||
| CIRO | Recommended | Acceptable Variation | Unacceptable Variation | ||
| Parotid Gland (ipsilateral) | Mean < 26 Gy (HN005) | Mean < 11 Gy | Mean < 26 Gy | Xerostomia | |
| Thyroid Gland | V25 Gy < 63.5% | V25 Gy < 70% | Hypothyroidism | ||
| Heart | Mean < 20-38 Gy (LU004, RTOG 1010) | Mean < 8 Gy | Mean < 15 Gy | Mean = 20 Gy | Cardiac complications |
| Left Anterior Descending Artery | V15 Gy < 10% | V15 Gy < 15% | Coronary artery disease | ||
| Lungs | Mean < 18-20 Gy (LU005, LU004) V20 Gy < 30-37% (GI006, LU004) | Mean < 10 Gy V20 Gy < 20% | Mean < 13.5 Gy V20 Gy < 30% | Mean = 20 Gy V20 Gy = 40% | Pneumonitis |
| Breast | D10% < 17.7 Gy (B51) | V4 Gy < 10% | V4 Gy = 10% | Breast cancer | |
| Liver | Mean < 21-34 Gy (GI006, QUANTEC) | Mean < 15 Gy | Mean < 17 Gy | Mean = 24 Gy | Radiation-induced liver disease |
| Spleen | Mean < 45 Gy (GI006) | Mean < 10 Gy | Mean < 20 Gy | Infection-related mortality | |
| Pancreas | Mean < 10 Gy | Mean < 21 Gy | Diabetes | ||
| Kidney (individual) | Mean < 18 Gy (QUANTEC) | Mean < 8 Gy | Mean < 11 Gy | Mean = 18 Gy | Renal dysfunction |