Doublet chemotherapy vs. single-agent therapy with 5FU in elderly patients with metastatic colorectal cancer. a meta-analysis

Abstract

Background: The clinical benefit of first-line doublet chemotherapy (including oxaliplatin or irinotecan) compared to single-drug therapy (5FU) in elderly patients (>70 or >75 years old) with metastatic colorectal cancer (MCRC) is controversial. Therefore, we undertook a meta-analysis of all published phase III studies.

Material and methods: We performed a PubMed search using keywords metastatic colorectal cancer, phase III studies, oxaliplatin, irinotecan, survival. We also screened Society of Clinical Oncology (ASCO) and European Society of Medical Oncology (ESMO) proceedings. Few studies have been published corresponding to our inclusion criteria. The efficacy outcomes were overall survival (OS) and progression-free survival (PFS). Toxicity was also examined when available. Hazard ratios (HRs) with their 95 % confidence intervals (CI) were collected from the studies and pooled. By convention, HRs <1 corresponded to a better outcome for doublets. p values <0.05 were considered statistically significant. A fixed-effect model was used. We used Comprehensive Meta-Analysis Software (Biostat, Englewood, NJ, USA).

Results: This meta-analysis (MA) included five original studies (Mitry and Venderbosch for CAIRO both assessing irinotecan, De Gramont and Seymour for FOCUS2 and Ducreux assessing oxaliplatin) and an already published MA (Folprecht) of four trials comparing FOLFIRI with 5FU (Saltz, Douillard, Köhne and Seymour). Our MA included 1225 patients (70 % men). For age, we chose a cut-off of 70 years for oxaliplatin and a cut-off of 75 years for irinotecan. The performance status (PS) score was 0-1 in about 90 % of patients except for the studies by Mitry and Seymour FOCUS2 which both included 30 % of PS2 patients. Overall, doublet chemotherapy, compared to 5FU alone, did not improve OS (HR = 1.00; CI: 0.89-1.13) but significantly improved PFS (HR = 0.82; CI: 0.72-0.93). When assessed separately, FOLFIRI and FOLFOX both significantly improved PFS (HR = 0.83; 0.68-1.00 and HR = 0.81; 0.68-0.97, respectively). The main grade 3-4 toxicities for FOLFIRI were diarrhoea, nausea, vomiting and neutropenia, which occurred significantly more often than with 5FU alone.

Conclusion: Addition of oxaliplatin or irinotecan to 5FU in metastatic CRC significantly improved PFS in elderly patients more than 70 years old but was associated with an increased risk of toxicity as shown for irinotecan.

Keywords: Doublet chemotherapy; Elderly; Irinotecan; Meta-analysis; Metastatic colorectal cancer; Oxaliplatin; Survival.