Purpose: Bevacizumab has demonstrated survival benefit in metastatic colorectal cancer (mCRC) patients when combined with chemotherapy. Several randomized clinical studies have evaluated bevacizumab in combination with chemotherapy. Meta-analysis was performed to better assess the efficacy and safety of bevacizumab with chemotherapy for mCRC.
Materials and methods: Five clinical trials randomizing a total of 3,103 mCRC patients to chemotherapy alone or to the combined treatment of chemotherapy plus bevacizumab were identified. The efficacy data included progression-free survival (PFS), overall survival (OS), and overall response rate (ORR), and the safety data contained the 60-day all-cause mortality rate, adverse events (AEs), and specific toxicity such as hypertension, thrombosis, bleeding, proteinuria, gastrointestinal perforation, diarrhea, and leucopenia.
Result: There was a significant PFS benefit (P = 0.00; hazards ratio [HR] = 0.66) and OS benefit (P = 0.00; HR = 0.77) in favor of the combined treatment. The ORR was significantly higher on the bevacizumab-containing arm (P = 0.021; relative risk [RR] = 1.5), while CR was comparable between the two arms (P = 0.09). A higher incidence of grade 3/4 AEs, grade 3/4 hypertension, grade 3/4 thromboembolic/thrombotic events, grade 3/4 bleeding, and gastrointestinal perforation was associated with the bevacizumab group. The two treatment groups were similar in terms of grade 3/4 proteinuria, grade 3/4 leukopenia, grade 3/4 diarrhea, and the 60-day all-cause mortality rate.
Conclusion: The addition of bevacizumab to chemotherapy confers a clinically meaningful and statistically significant improvement in OS, PFS, and ORR. Its side effects are predictable and manageable and do not compound the incidence or severity of toxicities from chemotherapy.