Abstract
BACKGROUND AND AIM: Extensive-stage small cell lung cancer (ES-SCLC) is characterized by rapid progression and a high incidence of metastasis, particularly to the bones. Patients with bone-only metastasis (BOM) face unique challenges in prognosis and treatment. This study aimed to develop a graded prognostic assessment (GPA) model by retrospectively investigating prognostic factors in ES-SCLC with BOM to estimate survival time and enhance clinical decision-making. METHODS: The primary endpoint of the study was overall survival. We included ES-SCLC patients with BOM diagnosed between 2010 and 2022 at two hospitals. The Log-rank test and Cox proportional hazards model were employed to analyze prognostic factors. A GPA model was established using significant factors based on their hazard-ratios in the training set and subsequently validated by the validation set. RESULTS: A total of 274 patients were included, with 164 in the training cohort and 110 in the validation cohort. Significant independent prognostic factors incorporated into the GPA model included bone metastasis status, weight loss, treatment with antiresorptive drugs, immunotherapy and thoracic radiotherapy. A GPA score of 1 was assigned to patients with oligo-metastasis, no weight loss, and who received antiresorptive drug treatment, immunotherapy, or thoracic radiotherapy. The corresponding alternative factors were assigned scores of 4.671, 2.100, 1.706, 2.116 and 1.687, respectively. The median survival times for patients with GPA scores of 1.000 to 3.570, 3.610 to 13.443, and 16.548 to 59.736 were 38.9, 15.6, and 7.7 months in the training set (P < 0.001) and 36.2, 15.7, and 8.9 months in validation set (P < 0.001). CONCLUSION: The identified prognostic factors significantly influenced survival time for ES-SCLC patients with BOM. The GPA model developed in this study may serve as a valuable tool for estimating life expectancy and guiding treatment decisions.