Adjuvant oxaliplatin- or irinotecan-containing chemotherapy improves overall survival following resection of metachronous colorectal liver metastases

Purpose: Adjuvant systemic 5-fluorouracil (5-FU)-based chemotherapy improves survival after resection of synchronous colorectal liver metastases (CLMs), but not metachronous. We retrospectively examined if adjuvant chemotherapy with new regimen containing oxaliplatin or irinotecan improved survivals after resection of metachronous CLMs. Methods: Between 2000 and 2007, 52 patients having undertaken resection of metachronous CLMs with curative intent were identified from Taipei Veterans General Hospital hospitalization registry. One patient with perioperative mortality and another being lost to follow-up within 3 months after metastasectomy were excluded. Thirty-one patients experienced six to 12 cycles of FOLFOX or FOLFIRI chemotherapy while 19 patients with 5-FU/leucovorin (LV)-based chemotherapy following CLM resection. The primary end point was disease-free survival (DFS) and secondary end point, overall survival (OS). Results: By the univariate analysis, median DFS was 34.3 months in the FOLFOX/FOLFIRI group vs 14.2 months in the 5-FU/LV group (P=0.022). The median OS and 5-year survival rates were longer than 57.7 months (not reached, with median follow-up of 35.5 months) and 54.0%, respectively, in the FOLFOX/FOLFIRI group compared to 49 months and 34.6% in the 5-FU/LV group (P=0.027). FOLFOX/FOLFIRI chemotherapy was shown by multivariate analyses to be an independent factor predicting a better DFS (hazard ratio [HR]=0.37; 95% CI: 0.15-0.94; P=0.036) and a better OS (HR=0.27; 95% CI: 0.083-0.86, P=0.026) than 5-FU/LV-based. Conclusions: Adjuvant FOLFOX/FOLFIRI chemotherapy following resection of metachronous CLMs is demonstrated to have better DFS and OS than 5-FU/LV chemotherapy.