Second-line chemotherapy in advanced and metastatic CRC.

Background: Chemotherapy is widely used in colorectal cancer that has relapsed or failed to respond to first-line treatment.

Objectives: To determine the efficacy of second-line chemotherapy for the treatment of advanced colorectal cancer.

Search Strategy: We performed electronic searches in the following databases: MEDLINE (via PubMed; 1964-September 2007), EMBASE (via OVID; 1980-September 2007) and The Cochrane Library 2007, Issue 2.

Selection Criteria: Studies assessing the efficacy of second-line chemotherapy (single or combined treatment with any chemotherapeutic agent, at any dose and number of cycles) in patients with advanced colorectal cancer that progressed, recurred or did not respond to first-line chemotherapy.

Data Collection And Analysis: A descriptive analysis of the included trials was performed, due to the huge clinical heterogeneity between them.

Main Results: Seven randomized controlled trials (RCTs) were included; one of high quality, five of moderate quality, and one conference abstract. Second-line chemotherapy (irinotecan) showed moderate benefits in overall survival and progression-free survival over Best Supportive Care (BSC) and fluorouracil (5-FU). Fractionated administration has not proven to be more beneficial and is more toxic. Definitive results concerning the benefits and risks of oxaliplatin are pending publication.

Authors' Conclusions: Second-line chemotherapy is effective in prolonging time to progression and survival in patients with advanced colorectal cancer. Further RCTs are needed to assess the optimal chemotherapy regimen.