Liver resection for metastatic colorectal cancer: Assessing the risk of occult irresectable disease

Background: Liver resection is standard therapy for selected patients with metastatic colorectal cancer. Extrahepatic metastases and inability to remo ve all hepatic disease usually preclude curative resection and are the most common contraindications. This study analyzes irresectability in patients considered to have resectable disease taken to operation for potentially cu rative hepatic resection. We describe preoperative factors associated with irresectability and propose a preoperative scoring system that identifies p atients at particularly high risk for occult irresectable disease. Study Design: Patients considered to have resectable hepatic colorectal met astases were identified from a prospective database. Intraoperative finding s that precluded liver resection were recorded. Demographic data, character istics of the primary tumor, and characteristics of the hepatic metastases were recorded and analyzed. Results: From April 1992 through July 1997, 416 patients were explored with the intention of performing a potentially curative liver resection; 329 (7 9%) were resected. Eighty-seven patients (21%) had apparently resectable tu mors on preoperative imaging but irresectable disease at laparotomy. Forty- four patients (51%) had irresectable disease limited to the liver; 32 had e xtensive bilobar disease not appreciated before surgery, and 12 were not re sected for technical or other reasons unrelated to disease extent. Forty-th ree patients (49%) had extrahepatic disease, 31 of whom had resectable hepa tic tumors. Of the several preoperative factors analyzed, only the estimate d number of hepatic tumors was an independent predictor of irresectable fin dings at operation. This held true for patients with extrahepatic metastase s and those with extensive hepatic disease. From these data, we devised a p reoperative scoring system that estimates the probability of finding occult irresectable disease. Resectability ranged from 95% in patients with a sco re of 0 (solitarr, unilobar) to 62% in those with a score of 3 (multiple, b ilobar; p = 0.0001). The predictive value of this scoring system was then v alidated by applying it prospectively to an additional group of 118 patient s taken to surgery for resection; the results were similar. Conclusions: Standard preoperative investigations predicted resectability i n 79% of patients with hepatic colorectal metastases. Unresectable disease limited to the liver and extrahepatic disease were seen with nearly equal f requency. The majority of patients with extrahepatic metastases had resecta ble hepatic disease (31 of 43, 72%). A preoperative scoring system is propo sed that identifies patients at high risk for unrecognized irresectable dis ease and may help focus the use of additional diagnostic modalities such as laparoscopy and positron emission tomography (PET). (J Am Coll Surg 1999; 188:33-42. (C) 1999 by the American College of Surgeons).