Assessing the optimal duration of chemotherapy in patients with colorectal liver metastases

BACKGROUND AND OBJECTIVES: Few studies have addressed the optimal duration of chemotherapy, particularly prior to liver resection for colorectal liver metastases (CLM). The purpose of this retrospective analysis was to evaluate time to maximal response in patients receiving systemic +/- hepatic arterial infusion (HAI) chemotherapy alone for the treatment of CLM. METHODS: We reviewed 35 patients with CLM on clinical trials of HAI floxuridine/dexamethasone plus systemic oxaliplatin with 5-fluorouracil/leucovorin or irinotecan (PUMP + SYSTEMIC). We retrospectively identified 35 patients with CLM who received first-line systemic 5FU/leucovorin/oxaliplatin (FOLFOX) +/- bevacizumab (SYSTEMIC) during the same time period. Measurable disease was evaluated on CT scans performed at 2-month intervals. The sum of the products of bi-dimensional tumor measurements for representative lesions was compared both to baseline imaging and between consecutive time points. RESULTS: In responders to therapy, mean cumulative tumor reduction increased from 61% at 2 months to 73% at 4 months in the PUMP + SYSTEMIC group (P < 0.01) and from 39% to 56% in the SYSTEMIC group (P < 0.01). No significant incremental tumor reduction occurred between 4 and 6 months in either group. CONCLUSIONS: In responders to preoperative therapy, surgical resection should be considered after 2-4 months, when most patients have achieved maximal response.