Trends in perioperative systemic chemotherapy for resected colorectal liver metastases: A Surveillance, Epidemiology, and End Results-Medicare analysis.

Abstract

The optimal treatment strategy for patients undergoing curative-intent resection of colorectal liver metastases remains uncertain. While perioperative and adjuvant chemotherapy are widely used, randomized trials have not demonstrated a consistent overall survival benefit, and guidelines continue to endorse approaches ranging from surgery alone to multimodal therapy. Randomized studies evaluating perioperative or adjuvant chemotherapy-along with trials incorporating biologic therapy-have shown improvements in disease control but inconsistent overall survival benefit. We evaluated national trends in perioperative chemotherapy use and factors associated with receipt over 2 decades. Using Surveillance, Epidemiology, and End Results-Medicare (2000-2020), we identified patients who underwent hepatectomy for liver-only colorectal liver metastases. Perioperative chemotherapy was defined as systemic therapy within 6 months before surgery, 4 months after, or both. Temporal trends were assessed, multivariable logistic regression identified predictors of treatment, and overall survival was evaluated with Kaplan-Meier and adjusted Cox models. Among 42,235 patients with liver-only metastases, 3,752 (9%) underwent resection; 54% of these received perioperative chemotherapy (14% preoperative only, 22% postoperative only, and 18% both). Use declined modestly over time (odds ratio per year, 0.97; 95% confidence interval, 0.95-0.98; P < .001). Chemotherapy was more common with rectal primaries (odds ratio, 1.42; 95% confidence interval, 1.05-1.92; P = .02) and synchronous disease (odds ratio, 1.57; 95% confidence interval, 1.30-1.92; P < .001) but less likely in patients ≥75, <65, and with overlapping or unspecified primaries. Perioperative chemotherapy was independently associated with improved overall survival, greatest with both preoperative and postoperative regimens (hazard ratio, 0.54; 95% confidence interval, 0.47-0.60; P < .001). In this national cohort of adults, perioperative chemotherapy was used in half of patients undergoing hepatectomy for colorectal liver metastases with minimal change over time and was associated with improved survival, supporting continued multimodal management.