Effect of age on the effectiveness of the first-line standard of care treatment in patients with metastatic colorectal cancer: systematic review of observational studies

PurposeMost metastatic colorectal cancer (mCRC) patients are elderly. This systematic review identifies and describes observational studies evaluating the influence of age on first-line treatment effectiveness in real-world practice.MethodsMedline and EMBASE were searched up to May 2016. The included studies were those that investigated first-line treatment of mCRC and reported age groups and overall survival (OS), progression-free survival (PFS) or overall response rate (ORR) were included. Studies published before 2008 were excluded. Study quality was assessed using the Newcastle-Ottawa Scale. Data were evaluated by age group (<70 vs.>= 70years; 65-75vs.>= 75years) and outcome. A pooled survival median was calculated for patients (cutoff=70years).ResultsIn total,11 articleswith 11,063 patients were included. Four studies using a cutoff of 70years of agereported OS and PFS, and twostudies reported ORRs. In terms of OS, all studiesshowed a higher OS for those <70yearsof age than for those >= 70yearsof age. PFS did notfind differences by age. For ORRs, one study favoured the younger group, while the second study did not differ by age. Based on three studies, the pooled medians for <70years of ageand >= 70years of agewere the same for PFS (10.2) andwere 27.0 and 22.9 for OS, respectively. All included studies were of high or acceptable quality.ConclusionsThe results suggest that age has no effect on PFS. For ORR, the results were inconsistent between studies. Younger patients in general had better OS, which might be partly explained by more aggressive treatment. This treatment seemed not to be guided by performance status or number of metastatic sites.