Prognostic factors for metastatic colorectal cancer patients undergoing irinotecan-based second-line chemotherapy

No reports about factors that predict prognosis after second-line chemotherapy for metastatic colorectal cancer have been published.

We retrospectively analyzed 124 patients with metastatic colorectal cancer who received irinotecan-based second-line chemotherapy after first-line folinic acid/5-fluorouracil (5-FU)/oxaliplatin (FOLFOX) with or without bevacizumab.

A multivariate Cox model revealed 5 prognostic factors for worse survival: ECOG performance status 2, pathologically poorly differentiated adenocarcinoma, peritoneal metastasis, progression-free survival of first-line FOLFOX < 6 months, and lactate dehydrogenase ≥ 400 IU/L. When patients were categorized into 3 risk groups-patients without any prognostic factors (low-risk, n = 55), patients with one prognostic factor (intermediate-risk, n = 32), and patients with 2 or more prognostic factors (high-risk, n = 37)-overall survival from initiation of second-line chemotherapy was 23.5, 14.6, and 5.5 months, respectively. The proportion of patients who were eligible to receive further chemotherapy after disease progression was significantly lower in the high-risk group (41%) than in the intermediate- (67%) and low-risk (95%) groups.

Several prognostic factors for survival after second-line therapy and probability of receiving third-line chemotherapy were identified. This risk classification system might be useful for determining which patients should receive cetuximab in the second-line setting rather than the third-line setting.