For patients with metastatic colorectal cancer, the standard treatment is induction combination chemotherapy with a targeted agent. However, clinical trials that involved patients either continuing cytotoxic therapy until disease progression or observation have shown inconsistent efficacy results. To close this gap, a systematic review and network meta-analysis was conducted and revealed that continued induction therapy until progression offered no survival benefit compared with maintenance fluoropyrimidine with or without bevacizumab, and observation should be considered an acceptable option in patients with metastatic colorectal cancer.
For this study, results of which are published in JAMA Oncology, researchers analyzed data from MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Central Register of Controlled Trials on randomized clinical trials assessing various treatment methods for patients with treatment-naive metastatic colorectal cancer. The clinical trials of interest included in the study were those with patients with metastatic colorectal cancer who were treated with an initial period of cytotoxic chemotherapy (with or without a biologic) and then switched to one of the following strategies: observation; maintenance with bevacizumab, fluoropyrimidine, or both; or continuing the induction regimen until progression.
The investigators analyzed 5,540 patients aged 23 to 85 years old, and over half of the study population was male. After reviewing the data, the researchers discovered that there was no benefit of continuing full cytotoxic chemotherapy until progression versus observation in regard to progression-free survival and overall survival. However, maintenance therapy did show a progression-free survival benefit when compared with observation. In addition, all maintenance strategies showed a significant improvement in progression-free survival compared with observation.
"For patients with metastatic colorectal cancer, there is no benefit to continuing the full induction regimen until progression, without a period of either observation or maintenance treatment," conclude the study authors, led by Mohamad Bassam Sonobol, MD, of the Division of Hematology/Oncology at Mayo Clinic. "A maintenance strategy with a fluoropyrimidine, with or without the addition of bevacizumab, is preferred. However, given the lack of a clear [overall survival] benefit, shared decision-making should include observation as an acceptable alternative."
For More Information
Sonbol MB, Mountjoy LJ, Firwana B, et al (2019). The role of maintenance strategies in metastatic colorectal cancer: a systematic review and network meta-analysis of randomized clinical trials. JAMA Oncol. [Epub ahead of print] DOI:10.1001/jamaoncol.2019.4489
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