Survival after liver resection for metastatic colorectal carcinoma in a large population

Background: Previous reports of liver resection for metastatic colorectal cancer (CRC) are typically from single centers and cannot account for selection or referral bias. We measured longterm survival after liver resection for metastatic CRC in the province of Ontario, Canada (population 12 million). Study Design: The Ontario Cancer Registry is an administrative database that links all hospital records, pathology reports, and vital statistics for patients with a diagnosis of cancer. We used the Registry to identify and obtain information on all patients who underwent liver resection for metastatic CRC in calendar years 1996 to 2004. Pathology reports of the original CRC resection and subsequent liver resections were individually reviewed. Results: Eight hundred forty-one resections were performed at 43 centers across Ontario during the 9-year period, including wedge resection (n = 303; 36%); lobectomy (n = 466; 55%); and trisectionectomy (n = 72; 9%). Ninety-one percent and 54% of resections were performed at teaching and high-volume centers (> 80 resections), respectively. Most liver resections were performed more than 120 days after original CRC operation (672 of 841; 80%). Perioperative mortality was 3%. Unadjusted 1-, 3-, and 5-year survival after liver resection was 88%, 59%, and 43%, respectively. Survival was improved when resection was performed for fewer than 2 tumor nodules, at high-volume centers, or in the years 2001 to 2004. Conclusions: Results in this population-based series are consistent with those of single-hospital series assessing longterm survival after liver resection for metastatic CRC. These findings support continued efforts to aggressively identify and resect CRC liver metastases.