Cardiac-sparing radiotherapy for locally advanced non-small cell lung cancer



Turtle, Louise ORCID: 0000-0003-3491-5033, Bhalla, Neeraj, Willett, Andrew, Biggar, Robert, Leadbetter, Jonathan, Georgiou, Georgios, Wilson, James M, Vivekanandan, Sindu, Hawkins, Maria A, Brada, Michael
et al (show 1 more authors) (2021) Cardiac-sparing radiotherapy for locally advanced non-small cell lung cancer. RADIATION ONCOLOGY, 16 (1). 95-.

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Abstract

<h4>Background</h4>We have carried out a study to determine the scope for reducing heart doses in photon beam radiotherapy of locally advanced non-small cell lung cancer (LA-NSCLC).<h4>Materials and methods</h4>Baseline VMAT plans were created for 20 LA-NSCLC patients following the IDEAL-CRT isotoxic protocol, and were re-optimized after adding an objective limiting heart mean dose (MD<sub>Heart</sub>). Reductions in MD<sub>Heart</sub> achievable without breaching limits on target coverage or normal tissue irradiation were determined. The process was repeated for objectives limiting the heart volume receiving ≥ 50 Gy (V<sub>Heart-50-Gy</sub>) and left atrial wall volume receiving ≥ 63 Gy (V<sub>LAwall-63-Gy</sub>).<h4>Results</h4>Following re-optimization, mean MD<sub>Heart</sub>, V<sub>Heart-50-Gy</sub> and V<sub>LAwall-63-Gy</sub> values fell by 4.8 Gy and 2.2% and 2.4% absolute respectively. On the basis of associations observed between survival and cardiac irradiation in an independent dataset, the purposefully-achieved reduction in MD<sub>Heart</sub> is expected to lead to the largest improvement in overall survival. It also led to useful knock-on reductions in many measures of cardiac irradiation including V<sub>Heart-50-Gy</sub> and V<sub>LAwall-63-Gy</sub>, providing some insurance against survival being more strongly related to these measures than to MD<sub>Heart</sub>. The predicted hazard ratio (HR) for death corresponding to the purposefully-achieved mean reduction in MD<sub>Heart</sub> was 0.806, according to which a randomized trial would require 1140 patients to test improved survival with 0.05 significance and 80% power. In patients whose baseline MD<sub>Heart</sub> values exceeded the median value in a published series, the average MD<sub>Heart</sub> reduction was particularly large, 8.8 Gy. The corresponding predicted HR is potentially testable in trials recruiting 359 patients enriched for greater MD<sub>Heart</sub> values.<h4>Conclusions</h4>Cardiac irradiation in RT of LA-NSCLC can be reduced substantially. Of the measures studied, reduction of MD<sub>Heart</sub> led to the greatest predicted increase in survival, and to useful knock-on reductions in other cardiac irradiation measures reported to be associated with survival. Potential improvements in survival can be trialled more efficiently in a population enriched for patients with greater baseline MD<sub>Heart</sub> levels, for whom larger reductions in heart doses can be achieved.

Item Type: Article
Uncontrolled Keywords: NSCLC, Cardiac-sparing, Radiotherapy, Heart, Survival
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Clinical Directorate
Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology
Depositing User: Symplectic Admin
Date Deposited: 15 Jun 2021 08:59
Last Modified: 18 Jan 2023 22:35
DOI: 10.1186/s13014-021-01824-3
Open Access URL: https://doi.org/10.1186/s13014-021-01824-3
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3126029