Determinants of unresectability and outcome of patients with occult colorectal hepatic metastases.

BACKGROUND Patients chosen for liver resection of colorectal liver metastases are a select group with minimal disease, favorable tumor biology and earlier presentation when compared to unresectable patients. Despite intense preoperative assessments, operative detection of occult unresectable disease is inevitable for a small group of patients. The aim of this study was to evaluate determinants of occult unresectability, and to establish if patients with occult unresectable disease demonstrate survival benefits similar to resected patients, or more similar to patients diagnosed with metastatic disease who were never explored. METHODS A retrospective medical record review was performed on 171 patients with colorectal hepatic metastases who underwent exploration with the intent of performing a curative liver resection. Patient and tumor characteristics, operative findings and survival were evaluated. Univariate and multivariate analysis were performed to evaluate determinants of unresectability, and survival was determined by Kaplan-Meier analysis. RESULTS One hundred forty-six patients were completely resected and 25 patients were found to have occult unresectable disease during exploration. Of these 25 patients, 10 had more extensive hepatic disease than expected which precluded resection, while 15 patients had unexpected extrahepatic disease. Of the 15 patients with extrahepatic disease, 7 had otherwise resectable liver metastases. Only bilobar disease was a statistically significant finding associated with occult unresectability on multivariate analysis (P = 0.05). Resected patients had a median survival of 37 months, while unresected patients had a median survival of 17 months (P < 0.005). At 3 and 5 years, the overall survival for resected patients was 52% and 29%. The survival at 3 years for patients with occult unresectable disease was only 5%, with no 5 year survivors. CONCLUSIONS The majority of patients with occult unresectable colorectal hepatic metastases had bilobar disease or extrahepatic spread. Despite the process of patient selection that leads to an attempt for curative resection, patients with occult unresectable disease identified at exploration suffer from poor survival that approximates the outcome of patients never considered for resection.