Association of lung and heart dose with survival in patients with non-small cell lung cancer underwent volumetric modulated arc therapy
Received 8 January 2019
Accepted for publication 12 June 2019
Published 3 July 2019 Volume 2019:11 Pages 6091—6098
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Colin Mak
Peer reviewer comments 4
Editor who approved publication: Dr Rituraj Purohit
Lanxiao Shen,1,* Cong Liu,2,* Juebin Jin,3 Ce Han,1 Yongqiang Zhou,1 Xiaomin Zheng,1 Changfei Gong,1 Mengfeng Chen,4 Congying Xie,1 Xiance Jin1
1Radiation and Medical Oncology Department, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People’s Republic of China; 2Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, People’s Republic of China; 3Department of Medical Engineering, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People’s Republic of China; 4Respiratory Department, Third People’s Hospital of Yueqing, Wenzhou 325600, People’s Republic of China
*These authors contributed equally to this work
Background: Controversial conclusions had been reported in studies trying to confirm the impact of heart dose on overall survival (OS) reported in RTOG 0167 for non-small cell lung cancer (NSCLC) patients who underwent radiotherapy (RT). The purpose of this study is to investigate the association of lung and heart dosimetric parameters with OS in NSCLC patients treated by volumetric modulated arc therapy (VMAT).
Methods: Inoperable NSCLC patients treated by VMAT from March 2012 to December 2015 were retrospectively reviewed. OS and progression-free survival (PFS) were estimated with the Kaplan–Meier method. Univariate and multivariate analyses were conducted with Cox proportional hazards model. Multivariate model building was conducted using stepwise regression for variables with p-value smaller than 0.2 in the univariate analysis.
Results: There were 130 NSCLC patients enrolled in this study with a median age of 63 years (range from 34 to 82 y). The median prescription dose for these patients was 56 Gy (range 40–70 Gy) with a mean heart and lung dose of 14.8±8.5 Gy and 13.6±4.4 Gy, respectively. The rates of patients with above grade III radiation pneumonitis (RP) and fibrosis were 8.5% and 8.5%, respectively. The 2-year PFS and OS of these patients were 15.2% and 39.8%, with a median PFS and OS of 7.2 and 18.8 months, respectively. RP was correlated with OS (p=0.048) and lung V20 was associated with PFS (p=0.04) according to the univariate analysis. Multivariate analysis demonstrated that RP (HR 1.39, 95%CI 1.010–1.909, p=0.043) and heart V15 (HR 1.02, 95%CI 1.006–1.025 p=0.002) were progression factors of OS, and no factor was associated with PFS.
Conclusions: RP and heart V15 were associated with OS for patients with stage III NSCLC who underwent VMAT. Heart and lung dosimetric parameters were highly correlated with each other, sparing of heart and lung should be considered equally during the treatment planning.
Keywords: non-small cell lung cancer, volumetric modulated arc therapy, heart dosimetry, radiation pneumonitis, overall survival
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