Journal of Inflammation Research (Aug 2021)
Comparison of Radiation Pneumonitis in Lung Cancer Patients Treated with HT versus IMRT and Circulating Lymphocyte Subsets as Predicting Risk Factors
Abstract
Xin Zhang,* Dingyi Yang,* Yong Jiang, Luo Huang, Can Wang, Dan Tao, Xianfeng Liu, Yongyang Lei, Yongzhong Wu, Wei Zhou Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yongzhong Wu; Wei ZhouChongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, 181 Han Yu Road, Chongqing, 400030, People’s Republic of ChinaTel +86 18323064006Email [email protected]; [email protected]: We sought to compare the symptomatic radiation pneumonitis (RP) in lung cancer patients treated with helical tomotherapy (HT) versus intensity-modulated radiotherapy (IMRT), and examine the predictive value of circulating lymphocyte subsets affecting the occurrence of RP.Patients and Methods: Circulating lymphocyte subsets, clinical characteristics, dosimetric parameters and pulmonary function were collected from 130 lung cancer patients treated with HT (n = 53) or IMRT (n = 77) from 2016 through 2020. Symptomatic RP was compared between groups. Binary logistic regression was used to identify predictors of RP.Results: The IMRT group had larger planning target volume (319.9 vs 240.8 cc, P = 0.041); more ECOG performance status 0– 1 (96.1% vs 79.2%, P = 0.002); more stage III–IV disease (94.8% vs 37.6%, P = 0.028); and more combined systemic therapy (85.7% vs 69.8%, P = 0.022). Grade ≥ 2 RP were comparable between IMRT and HT groups (16.9% vs 15.1%, P = 0.785). For stage III–IV disease, IMRT was associated with lower lung V10 (31.9% vs 35.8%, P = 0.047) and lower incidence of grade 5 RP (0% vs 9.1%, P = 0.018). All lymphocyte subsets reduced after radiotherapy. The decrease degree of total T cell count and CD4+ T cell count were larger after IMRT than HT (P = 0.043, P = 0.021). In univariate analysis, the smoking status, lower baseline FEV1, and higher total T cell count, higher CD8+ T cell count, lower total B cell count, lower CD4+/CD8+ ratio after radiotherapy were associated with the development of grade ≥ 2 RP. The higher CD8+T cell count after radiotherapy was the only risk factor associated with grade ≥ 2 RP in multivariable analysis (OR 1.003; 95% CI: 1.000– 1.005; P = 0.044).Conclusion: IMRT was associated with lower lung V10 and less grade 5 RP than HT for stage III–IV lung cancer. Higher CD8+ T cell count after radiotherapy was associated with an increased risk of RP. HT may better preserve total T cell and CD4+ T cell than IMRT.Keywords: radiation pneumonitis, lung cancer, helical tomotherapy, intensity-modulated radiotherapy, circulating lymphocyte
