To evaluate the risk of pneumothorax in the percutaneous image-guided thermal ablation (IGTA) treatment of colorectal lung metastases (CRLM).Data regarding patients with CRLM treated with IGTA from five medical institutions in China from 2016 to 2023 were reviewed retrospectively. Pneumothorax and non-pneumothorax were compared using the Student's t test、Chi-square test and Fisher's exact test. Univariate logistic regression analysis was conducted to identify potential risk factors, followed by multivariate logistic regression (MLR) analysis to evaluate the predictors of pneumothorax. Interactions between variables were examined and used for model construction. Receiver operating characteristic (ROC) curves and nomograms were generated to assess the performance of the model.A total of 254 patients with 376 CRLM underwent 299 ablation sessions. The incidence of pneumothorax was 45.5%. The adjusted MLR model, incorporating interaction terms, revealed that tumor number (odds ratio [OR]=8.34 [95% confidence interval [CI]: 1.37-50.64]), puncture depth (OR=0.53 [95%CI: 0.31-0.91]), pre-procedure radiotherapy (OR=3.66 [95%CI: 1.17-11.40]), peri-bronchial tumor (OR=2.32 [95%CI: 1.04-5.15]), and emphysema (OR=56.83 [95%CI: 8.42-383.57]) were significant predictive factors of pneumothorax (all P<0.05). The generated nomogram model demonstrated a significant prediction performance, with an area under the ROC curve of 0.800 (95%CI: 0.751-0.850).Pre-procedure radiotherapy, tumor number, peri-bronchial tumor, and emphysema were identified as risk factors for pneumothorax in the treatment of CRLM using percutaneous IGTA. Puncture depth was found to be a protective factor against pneumothorax.Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.