Outcome of first line systemic treatment in elderly compared to younger patients with metastatic colorectal cancer: A retrospective analysis of the CAIRO and CAIRO2 studies of the Dutch Colorectal Cancer Group (DCCG)

Background. Metastatic colorectal cancer (CRC) is predominantly a disease of the elderly, therefore the current standards should be evaluated in this population. Material and methods. We evaluated in different age groups the outcome in terms of median overall and progression-free survival, response rate, disease control rate, relative dose intensity (RDI), tolerability, and global quality of life (QoL) of first-line capecitabine monotherapy (CAP) versus capecitabine + irinotecan (CAPIRI) and capecitabine + oxaliplatin + bevacizumab (CAPOX + BEV) in the CAIRO and CAIRO2 study, respectively. Patients were categorized into three age groups: age >75, 70-75 and <70 years. Results. Clinical outcomes were not significantly different among age groups, with the exception of a higher response rate from CAP treatment in the elderly. Elderly patients treated with CAPOX + BEV showed a trend towards a worse median overall survival compared to younger patients. Only treatment with CAP resulted in a higher incidence of grade 3-4 toxicity and a lower RDI in elderly versus younger patients. Treatment with CAP and CAPOX + BEV in elderly patients was significantly more often discontinued due to toxicity instead of progression to disease compared to younger patients. The increase in global QoL was comparable for the three age groups for each treatment regimen. Conclusion. We did not observe significant differences in survival outcomes between elderly and younger metastatic CRC patients with three different first-line systemic treatment regimens. Our data suggest that initial dose reduction of CAP monotherapy may be indicated in elderly patients.