Second-line systemic therapy for metastatic colorectal cancer

Area of Science:

• Oncology
• Clinical Pharmacology
• Evidence-Based Medicine

Background:

• Metastatic colorectal cancer (CRC) presents therapeutic challenges, particularly for patients unresponsive to first-line treatments.
• Identifying effective second-line systemic therapies is crucial for improving patient outcomes.

Purpose of the Study:

• To evaluate the efficacy and toxicity of second-line systemic therapies in metastatic CRC patients.
• To synthesize evidence from randomized controlled trials (RCTs) on survival, tumor response, and adverse events.

Main Methods:

• A systematic literature search was conducted across major databases (CENTRAL, MEDLINE, Embase) without language or date restrictions.
• Thirty-four RCTs involving 13,787 participants were included, analyzing efficacy (survival, tumor response) and toxicity (severe adverse effects).
• Meta-analysis was performed using random-effects models, employing hazard ratios (HRs) and risk ratios (RRs) with 95% confidence intervals (CIs).

Main Results:

• Chemotherapy (irinotecan) demonstrated superiority over best supportive care for overall survival (OS).
• Modern chemotherapy regimens (FOLFOX, irinotecan) outperformed older ones (5-fluorouracil) for progression-free survival (PFS) and OS.
• Irinotecan-based combinations and targeted agents combined with chemotherapy improved survival outcomes.
• Bevacizumab-containing regimens enhanced efficacy without significantly increasing severe adverse events (SAEs). Oral fluoropyrimidines reduced toxicity with maintained efficacy in oxaliplatin-based treatments.

Conclusions:

• Second-line systemic therapy provides a survival advantage for metastatic CRC patients.
• Combining targeted agents with conventional chemotherapy is particularly effective.
• Further research is necessary to optimize treatment regimens and personalize therapy selection.