The role of pulmonary metastasectomy (PM) for non-primary lung cancer: Umbrella review of meta-analyses

IntroductionDue to heterogeneous characteristics of primary cancers, the efficacy of pulmonary metastasectomy(PM) in non-primary lung cancers has not been investigated other than colorectal cancers. This study aims to investigate the clinical outcomes of PM for non-primary lung cancer. MethodsA systematic search for meta-analyses on PM for non-primary lung cancers was conducted, encompassing publications up to January 3, 2024. The analysis included seven primary cancer types: renal cell, breast, adrenocortical, head and neck cancers, melanoma, germ cell tumors, and sarcoma. Primary outcomes, overall survival, and recurrence rates post-PM were assessed using random-effect models to account for study heterogeneity. ResultsThis study included 16 systematic-review articles and 101 individual studies, involving 10,277 patients who underwent PM for non-primary lung cancer. Patients had a mean age of 48.0 years, with 68.4% being male. About half of the patients(47.1% [95%CI 40.8-53.5] presented with multiple metastatic lesions, and complete R0 resection achieved in 87.2% [95%CI 83.0-90.8]. The pooled 5-year overall survival (OS) rate post-PM was 41.2% [95%CI, 37.1-45.4%]. Patients with germ cell tumors demonstrated significantly higher survival rate than other cancers(p<0.05), while patients with melanoma exhibited the poorest outcome(p<0.05). During follow-up, 57.6%[95%CI 46.4-68.1] had recurrence; 48% of them had intrathoracic-only recurrence and 52% had extra-thoracic recurrence. ConclusionThis study underscores the survival benefits associated with PM. Overall survival rates following PM do not significantly differ based on primary cancer types, except for germ cell tumors and melanoma. These findings highlight the importance of recognizing and incorporating PM into clinical practice when appropriate. SynopsisSurgical resection for pulmonary metastasis from cancers other than lung cancer still holds a significant role in improving a patients prognosis. Though the recurrence rate is high, it could improve the chance of survival regardless of the primary cancer types.