Background: In the US, systemic chemotherapy is often administered after liver resection for hepatic colorectal metastases, even though no clinical trials data directly support this practice. The bias in America for chemotherapeutic treatment has made studies difficult. Until recently, no well accepted staging systems existed to categorize these patients with liver metastases, who have greatly varied prognoses.
Study design: All liver resections from an American and from a European tertiary care center performed between 1991 and 1998 were assembled from two prospective databases. Of 792 liver resections, the 518 patients treated with no chemotherapy (379 American, 139 European) were compared with 274 patients treated (240 American, 34 European) with 5-FU-based adjuvant chemotherapy. Patients treated by all other treatment regimens, including regional chemotherapy, were excluded, as were patients who died perioperatively. Patient survival analysis was performed by log-rank, with stratification by the clinical risk score (CRS, a staging system grading risk of recurrence by five clinical parameters: node-positive primary, short disease-free interval, large (> 5 cm) liver tumor, multiple liver tumors, and high carcinoembryonic antigen).
Results: Patients subjected to adjuvant chemotherapy had improved survival (p=0.007, log-rank test) even after stratification by clinical risk score (p=0.001, stratified log-rank test). In every clinical risk score category, patients subjected to adjuvant chemotherapy had a higher chance of survival (range 1.3 to 2.0 times). Adjuvant chemotherapy was an independent predictor of outcomes.
Conclusions: This large study, with patients stratified by risk of recurrence, demonstrates that systemic adjuvant chemotherapy, such as a 5-FU-based regimen, prolongs survival after hepatic resection for colorectal metastases.