Survival analysis and prognostic factors of diffuse bilateral intrapulmonary metastases in patients with non-small cell lung cancer

The study aimed to develop a nomogram utilizing the surveillance, epidemiology, and end results (SEER) database to predict the survival probability of diffuse bilateral intrapulmonary metastases (DBIM) in patients with non-small cell lung cancer (NSCLC). Clinical data from 2010 to 2020 were retrieved from the SEER database. Independent prognostic factors influencing overall survival (OS) were identified through univariate and multivariate Cox proportional hazards regression analyses conducted on the training cohort. Subsequently, a nomogram was constructed and its performance was assessed using concordance index (C-index), calibration curves, receiver operating characteristic (ROC) curves and area under the curve (AUC) results. Propensity score matching was employed to reduce variability in subgroup analysis comparing patients who received chemotherapy alone versus chemoradiotherapy. A total of 2075 patients were included in this study, wherein race, sex, marital status, age, household income, AJCC N stage, AJCC M stage, tumor size, total number of in situ/malignant tumors, bone metastasis, brain metastasis (BM), liver metastasis, surgery, and chemotherapy were independent prognostic factors. The nomogram demonstrated excellent performance, as evidenced by the high C-indexes, AUC results, and calibration curves. Subgroup analysis revealed potential benefits for women, patients with combined BM, and high-income individuals who received chemotherapy in conjunction with local radiotherapy. However, no significant impact on the 0.5-year survival rate was observed. Notably, a reliable nomogram was successfully developed to estimate the probability of survival in patients with DBIM. Overall, our study highlights the potential benefit of adding radiotherapy to chemotherapy specifically for women, those with combined BM, and high-income individuals.