There were no notable differences between the training and validation cohorts concerning various factors such as age, sex, KPS, smoking status, primary lesion location, EGFR mutation subtype, number, volume, location, and symptoms of brain metastases, T stage, N stage, presence of liver metastasis, bone metastasis, pleural metastasis, adrenal metastasis, as well as whether third-generation EGFR-TKI was combined with chemotherapy or anti-angiogenic therapy, and whether third-generation EGFR-TKI was used as first-line treatment. Here, EGFR is linked to bone metastasis.