A Single-Center Retrospective Exploration Of Targeted Maintenance Therapy In Advanced Colorectal Cancer

Background:Randomized trials have shown that maintenance therapy can provide survival benefits and reduce treatment-related toxicities when compared with intermittent treatment or continuous chemotherapy in patients with advanced colorectal cancer(CRC).The maintenance regimens currently used are fluoropyrimidines alone,Bevacizumab(Bev)alone,or fluoropyrimidines with Bev.The efficacy of maintenance therapy with anti-EGFR monoclonal antibody is controversial.However,some patients have received maintenance therapy with Cetuximab(Cet)in clinical practice because of the medical insurance in Zhejiang Province and the Chinese Patient Assistance Program.Therefore,we conducted this retrospective study to investigate the efficacy and safety of maintenance therapy with Cet or Bev.Methods:Patients with advanced CRC had been treated at the Second Affiliated Hospital of Zhejiang University School of Medicine and stable disease following induction chemotherapy from 2010 to 2018,and they were assigned to maintenance therapy with Cet(Cet group)or Bev(Bev group).Progression-free survival(PFS),the duration of maintenance therapy,and safety were analyzed.Kaplan-Meier method and Log-rank test were used to analyze differences in survival and prognosis between different groups.Cox multivariate regression analyses were performed to determine independent prognostic factors.Results:A total of 143 eligible patients were assigned to the Cet(n=79)or Bev(n=64)groups.In the Cet group,all patients had KRAS wild-type.The baseline characteristics were well balanced between the two groups,except for a higher percentage of patients with a left-sided primary tumour in the Cet group than in the Bev group(86.1% vs 62.5%,P<0.01).The median PFS was not significantly different between the Cet group and the Bev group: 5.9 months vs 6.3 months(HR 0.93;95%CI 0.65-1.32;P=0.68).The median duration of maintenance therapy in the Cet group was shorter than that in the Bev group: 4.1 months vs 4.8 months(HR 0.95;95%CI 0.67-1.33;P=0.76).In the Cet group,the median PFS with maintenance therapy after first-line induction chemotherapy and second-line chemotherapy or above were 6.9 months and 4.2 months,respectively(HR 1.52;95%CI 0.93-2.48;P=0.09).The incidence of adverse events during maintenance therapy was lower than that during induction chemotherapy.The frequency of any grade 3 adverse events was low,and there were no grade 4 adverse events.Conclusion:This study suggests that maintenance therapy with Cet or Bev can be considered an effective and safe option for patients with advanced CRC who have stable disease following induction chemotherapy(chemotherapy combined with Cet or Bev).