The only maintenance strategy to show a progression-free survival (PFS) benefit in patients with metastatic colorectal cancer (mCRC) after induction chemotherapy was fluoropyrimidine with or without bevacizumab, according to a systematic review and network meta-analysis recently reported in JAMA Oncology.1 

However without a “clear” overall survival (OS) benefit associated with maintenance therapy in this setting, observation remains an option for this patient population. 

A total of 12 trials with 5540 patients with mCRC were included in the systematic review. All trials had a low risk of bias, and all patients had received induction cytotoxic chemotherapy followed by 1 of the following: continuation of induction therapy until disease progression, maintenance therapy, or observation. Maintenance therapy included treatment with bevacizumab alone, a fluoropyrimidine alone, or bevacizumab and a fluoropyrimidine. 

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The meta-analysis revealed that patients who continued to receive induction chemotherapy until disease progression had neither a PFS (hazard ratio [HR], 0.71; 95% CI, 0.46-1.09) nor OS (HR, 0.95; 95% CI, 0.85-1.07) benefit compared with patients who were merely observed. 

In contrast, patients who received maintenance therapy with bevacizumab alone, a fluoropyrimidine alone, or bevacizumab and a fluoropyrimidine, had a significantly longer PFS (HR, 0.58; 95% CI, 0.43-0.77) compared with patients who only underwent observation. However, maintenance therapy did not ultimately lead to an OS benefit (HR, 0.91; 95% CI, 0.83-1.01).

Among the maintenance therapies, fluoropyrimidine alone or bevacizumab and fluoropyrimidine had the greatest probabilities of leading to a PFS (67.1% vs 99.8%, respectively) or OS (81.3% vs 73.2%, respectively) benefit. Bevacizumab alone had the lowest likelihood of PFS or OS benefit (36.5% and 32.6%, respectively).

The study researchers concluded that continuing the full induction regimen until progression without a period of either observation or maintenance treatment has “no benefit” and that fluoropyrimidine with or without bevacizumab is “preferred.”

“However, given the lack of a clear OS benefit, shared decision making should include observation as an acceptable alternative,” the study researchers wrote. 

Disclosure: Some of the authors of the study reported financial relationships with the pharmaceutical industry. For a full list of disclosures, please refer to the original study.

Reference

  1. Sonbol MB, Mountjoy LJ, Firwana B, et al. The role of maintenance strategies in metastatic colorectal cancer: A systematic review and network meta-analysis of randomized clinical trials [published online December 19, 2019]. JAMA Oncol. doi: 10.1001/jamaoncol.2019.4489