INTRODUCTION: This study aimed to describe the relationship between the number of colorectal liver metastases (CRLM) resected and the rate of postoperative complications and to determine a threshold level, if any, for which the risk of postoperative complications outweighs the benefit of resection of metastatic disease. METHODS: This is a retrospective analysis of the American College of Surgeons National Surgical Quality Improvement Program database from 2019 to 2021. Patients were divided into three major groups: one to two, three to four, and more than five CRLM. RESULTS: A total of 5124 patients had CRLM. Compared to patients with one to two and three to four CRLM, patients with 5+ resections were at increased risk of any complication (1655 [50% for one to two CRLM versus 697 [65%] for three to four CRLM versus 437 [76%] for 5+ LM
P = 0.001), surgical complications (1305 [40%] versus 556 [52%] versus 349 [60%]
P = 0.001), and medical complications (350 [10%] versus 141 [13%] versus 88 [16%]
P = 0.001). CONCLUSIONS: Our data demonstrate a significant increase in any surgical complications with three to four tumors resected and a significant increase in any surgical and medical complications and length of stay >
5 ds with five or more tumors resected.