Background: To assess the impact of primary-site surgery plus systemic therapy compared to systemic therapy alone on overall survival in common metastatic cancer types.
Methods: Data sources included Embase, PubMed, and Web of Science (1/1/1995-6/17/2020). Randomized controlled trials were included that enrolled patients diagnosed with the ten most common de novo metastatic cancer types in the Surveillance, Epidemiology, and End Results (SEER) database and randomized patients to resection of the primary site and systemic therapy vs. systemic treatment alone. Random-effects models were used to pool associations by cancer type.
Results: Eight studies with 1,774 patients evaluating the efficacy of surgery in breast, renal, stomach, and colorectal cancer were included. There was no statistically significant reduction in risk of all-cause mortality associated with surgical intervention for metastatic breast (HR=0.94, 95% CI 0.63-1.40) or renal cancer (HR=0.79, 95% CI 0.53-1.20), although results were heterogeneous (I2=73.7% and 80.6%, respectively). One study evaluating gastrectomy in metastatic stomach cancer found no benefit (HR=1.09, 95% CI 0.78-1.52), while a small trial suggested that surgery and hyperthermic intraperitoneal chemotherapy might be beneficial for colorectal cancer with peritoneal metastasis (HR=0.55, 95% CI 0.32-0.95).
Conclusions: Few randomized trials have evaluated cancer-directed surgery among patients with metastatic solid malignancies.