The Role of NK cells in Novel Nomogram Predicting Radiation Pneumonitis in LS-SCLC

Abstract Background Radiation pneumonitis (RP) is a common complication in patients with small cell lung cancer (SCLC) undergoing radiotherapy, and its occurrence is directly linked to the dosage received. The purpose of this study is to ascertain the predictive significance of the proportion of natural killer (NK) cells within the overall immune cell population in individuals with limited stage small cell lung cancer (LS-SCLC) undergoing radical radiotherapy. Method Participants included in a retrospective study at Jilin Cancer Hospital between 2019 and 2020 were individuals diagnosed with LS-SCLC who underwent radiation therapy. Statistical analysis encompassed an independent sample t-test or the Mann-Whitney-U test. The chi-square test or Fisher’s exact test for categorical variables. Logistic regression was used for multivariate analysis, and a predictive model using 'R' version 4.3.2 was constructed. The model's accuracy was assessed through ROC curves, AUC, and calibration curve. Additionally, the model's clinical relevance was evaluated through clinical decision curves and clinical impact curves. Result A total of 123 subjects were included. RP was observed in 25 individuals (20.3%). Results from the univariate analysis indicated that RP was significantly associated with the maximum esophageal dose (MXED), the mean ipsilateral lung dose (MILD), and the maximum ipsilateral lung dose (MXILD) (P < 0.01). Moreover, there were significant correlations between RP and the level of NK cells in the total immune cell population as well as response evaluation in the univariate analysis (all P < 0.05). The multivariate analysis further confirmed the significance of the level of NK cells proportion, MILD, and response evaluation in predicting RP. These factors were then utilized to construct a predictive nomogram model for RP. Conclusion NK cells can reflect inflammatory and tumor microenvironments. The proportion level of NK cells in overall immune cell population can serve as a predictive factor for radiation pneumonitis in LS-SCLC patients undergoing thoracic radiation. A nomogram incorporating the proportion level of NK cells in the immune cell population holds potential for future clinical applications.