A clinical research of SII, PNI and LDH before radiotherapy predicts the radiation pneumonia

Objective To explore the predictive value of systemic immune-inflammation index (SII), prognostic nutritional index (PNI), and lactate dehydrogenase (LDH) measured in peripheral blood before radiotherapy on the incidence of radiation pneumonia (RP) in patients with thoracic tumors, and to identify factors influencing the occurrence of RP grade ≥ 2 RP. Methods A retrospective analysis was conducted on 115 patients with thoracic tumors who received intensity-modulated radiotherapy at Xuzhou First People's Hospital from July 2021 to December 2022. According to the occurrence of RP, patients were divided into an RP group (27 cases) and non-RP group (88 cases). Logistic regression analysis was used to examine the factors related to the occurrence of RP after radiotherapy, and the receiver operating characteristic (ROC) curve was used to evaluate the predictive value of SII for RP occurrence before radiotherapy. Results The incidence of RP of grade≥2 was 23.48% (27/115, grade 2 was 15 patients, grade 3 was 9 patients and grade 4 was 3 patients). The univariate analysis showed that there were statistically significant differences in smoking history, concurrent chemoradiotherapy, immunotherapy history, levels of V₂₀ and SII before radiotherapy between RP group and non-RP group (P＜0.05). Multivariate regression analysis indicated that smoking history, immunotherapy history, levels of V₂₀ and SII before radiotherapy were independent risk factors for RP in patients with thoracic tumor after radiotherapy (OR>1 and P＜0.05). The ROC curve revealed that the threshold, sensitivity, and specificity of RP predicted by SII before radiotherapy were 1 107.46, 0.704 and 0.659, respectively. Conclusions Smoking history, immunotherapy history, levels of V₂₀ and SII before radiotherapy are all independent risk factors of RP in patients with thoracic tumor, and the level of SII before radiotherapy has a certain value in predicting the occurrence of RP.