Impact of lung and cardiac dose on the survival of oesophageal cancer patients following single modality radiotherapy
Session type: Poster / e-Poster / Silent Theatre session
Introduction: Late cardiac toxicity after radiotherapy has traditionally been reported for several disease sites, including breast cancer and Hodgkin’s lymphoma. Recently, the Radiation Therapy Oncology Group 0617 trial identified cardiac radiation dose as a strong predictor of survival for locally advanced non-small cell lung cancer patients following chemoradiotherapy with conventional dose escalated regimes. However, the effects of radiotherapy for other thoracic malignancies such as oesophageal cancer where significant cardiac doses are given has yet to be studied. In this single-centre retrospective analysis, we assess the impact of cardiac and lung dose on overall survival on oesophageal cancer patients treated in our institution with single modality radiotherapy from 2005-2016.
Methods: We reviewed the records of 51 stage I-IV oesophageal cancer patients treated at our institution with single modality hypofractionated radiotherapy (55Gy/20# in 4 weeks) between 2005 to 2016. Patient demographics, tumour characteristics, survival and dosimetric data were recorded. Multiple dose-volume histogram (DVH) parameters for heart and lung (max and mean dose, V5Gy, V10Gy, V15Gy, V20Gy, V25Gy, V30Gy, V35Gy, V40Gy, V45Gy and V50Gy) were extracted for analysis. The impact of these parameters was assessed using Cox regression.
Results: Median follow-up was 61 months (range:32-117 months). Median overall survival was 15 months (range:2-80 months). Several lung DVH parameters (V35Gy, V40Gy, V45Gy) were determined to be independent predictors of survival with the V40Gy showing the strongest correlation (HR=1.206, 95% CI=1.021-1.424, p = 0.028). The cardiac DVH parameters only showed a tendency towards statistical significance (e.g. mean heart dose:HR= 1.021, 95% CI=0.999-1.044, p = 0.064).
Conclusion: We identified lung dose as an independent predictor of survival following single modality radiotherapy with cardiac DVH parameters showing a trend that didn’t reach statistical significance. While these findings warrant further study in a larger cohort, current planning practice should focus on minimizing lung dose to impact outcomes.