Primary Tumor Resection and Survival Benefit in Patients with Synchronous Metastatic Primary Malignant Bone...

Background: The survival benefit of primary tumor resection (PTR) in patients with synchronous metastatic primary malignant bone neoplasms (PMBNs) remains controversial. We aimed to evaluate the association between PTR and survival outcomes using a large population-based cohort with rigorous confounding control. Methods: Patients diagnosed with synchronous metastatic PMBNs (osteosarcoma, chondrosarcoma, Ewing sarcoma, and chordoma) between 2004 and 2022 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were stratified by receipt of PTR. Propensity score matching (PSM; 1:1 nearest-neighbor, caliper = 0.03) was applied to balance baseline covariates. Kaplan-Meier analysis with log-rank testing and multivariable Cox proportional hazards regression stratified by matched pairs were used to assess overall survival (OS) and cancer-specific survival (CSS). Subgroup analyses were performed across four histological subtypes. Results: A total of 1046 patients were included (resection: n = 658, 62.9%; no resection: n = 388, 37.1%). After PSM, 488 patients (244 per group) were retained. In the matched cohort, PTR was independently associated with significantly improved Overall survival (OS) (HR = 0.34, 95% CI: 0.21-0.54, p < 0.001) and cancer-specific survival (CSS) (HR = 0.35, 95% CI: 0.22-0.55, p < 0.001). Subgroup analyses demonstrated significant survival benefit in osteosarcoma and chondrosarcoma (both p < 0.001), but not in Ewing sarcoma or chordoma. Conclusions: PTR is associated with a significant survival benefit in selected patients with synchronous metastatic PMBNs, particularly those with osteosarcoma and chondrosarcoma. These findings support individualized, multidisciplinary decision-making regarding surgical intervention in this population.