Effect of Education and Standardization of Cardiac Dose Constraints on Heart Dose in Lung Cancer Patients Receiving Definitive Radiation Therapy Across a Statewide Consortium
Herr DJ, Hochstedler K, Yin H, Dess RT, Matuszak MM, Grubb M, Dominello MM, Movsas B, Kestin LL, Bergsma DP, Dragovic AF, Grills IS, Hayman JA, Paximadis PA, Schipper M, and Jolly S. Effect of Education and Standardization of Cardiac Dose Constraints on Heart Dose in Lung Cancer Patients Receiving Definitive Radiation Therapy Across a Statewide Consortium. Int J Radiat Oncol Biol Phys 2021; 111(3):S126.
Int J Radiat Oncol Biol Phys
Purpose/Objective(s): Cardiac radiation exposure is associated with an increased rate of adverse cardiac events in patients receiving radiation therapy for locally advanced non-small cell lung carcinoma (NSCLC). Previous analysis of practice patterns within the statewide Michigan Radiation Oncology Quality Consortium (MROQC) revealed 1 in 4 patients received a mean heart dose > 20 Gy and significant heterogeneity existed among treatment centers in using cardiac dose constraints. The purpose of this study is to analyze the effect of education and initiation of standardized cardiac dose constraints on heart dose across a statewide consortium.
Materials/Methods: From 2012 to 2020, 1604 patients from 27 academic and community centers who received radiation therapy for locally advanced NSCLC were included in this analysis. Dosimetric endpoints including mean heart dose (MHD), mean lung dose, and mean esophagus dose were calculated using data from dose-volume histograms. These dose metrics were grouped by year of treatment initiation for all patients. Education regarding data for cardiac dose constraints was discussed in small lung cancer working group meetings and consortium-wide starting in 2016. This was followed in 2018 by implementation of a quality metric requiring mean heart dose < 20 Gy while maintaining dose coverage (D95) to the tumor. Dose metrics were compared before (2012-2016) and after (2017-2019) initiation of interventions targeting cardiac constraints. Statistical analysis was performed using the Wilcoxon Rank Sum test.
Results: Following education and implementation of the heart dose performance metric, mean MHD declined from an average of 12.2 Gy pre-intervention to 10.4 Gy post-intervention, and the percentage of patients receiving MHD > 20 Gy reduced by half. Mean lung dose and mean esophagus dose did not increase, and tumor coverage remained unchanged.
Conclusion: Education and implementation of a standardized cardiac dose quality measure across a statewide consortium was associated with a reduction of mean heart dose in patients receiving radiation therapy for locally advanced NSCLC. These dose reductions were achieved without sacrificing tumor coverage, increasing mean lung dose or mean esophagus dose. Analysis of the clinical ramifications of the reduction in cardiac doses is ongoing.