Age-dependent differences in first-line chemotherapy in patients with metastatic colorectal cancer: the DISCO study

摘要

Objectives: First-line chemotherapy for metastatic colorectal cancer (mCRC) is effective and feasible in selected older patients. We investigated age-dependent differences in treatment and outcomes in patients with mCRC in clinical practice.Material and methods: A retrospective study of 654 patients with mCRC referred to first-line chemotherapy in 2008-2014. Patients were divided into two age groups: 50-69 and >70 (older patients). Binary outcomes were analyzed by logistic regression. Progression-free survival (PFS) and overall survival (OS) were analyzed by Cox proportional hazards regression, CRC-specific and other-cause mortality with Fine and Gray proportional hazard model for the sub-distribution of a competing risk. Results: After adjusting for performance status (PS) and comorbidity, older patients were more likely to receive monotherapy (adjusted odds ratio (aOR) = 9.00, 95% confidence interval (Cl) 4.52-17.91), lower doses, and no additional targeted therapy (aOR= 1.89, 95% Cl 1.28-2.78) than younger patients. Yet, older patients experienced more toxicity and hospitalizations (aOR=1.53, 95% Cl 1.08-2.17). Among those treated, older patients had shorter PFS (hazard ratio (HR) = 1.32, 95% Cl 1.11-1.57), but after adjusting for PS and comorbidity, PFS was similar. No significant difference was found in CRC mortality (HR=1.15, 95% Cl 0.95-1.40) between age groups. Poor PS was associated with shorter OS and PFS and higher CRC mortality.Conclusions: In the DISCO study, older patients with mCRC received less aggressive first-line chemotherapy. Yet, they experienced more toxicity. Younger and older patients had similar CRC mortality. Shorter PFS and higher CRC mortality were observed in patients with poor PS.Abbreviations: aOR: adjusted odds ratio; EGFR: epidermal growth factor receptor; Capox: capecitabine and oxaliplatin; CGA: comprehensive geriatric assessment; Cl: confidence interval; CRC: colorectal cancer; Folfox: 5-fluorouracil and oxaliplatin; 5-FU: 5-fluorouracil; HR: hazard ratio; mCRC: metastatic colorectal cancer; MSI: microsatellite instability; OR: odds ratio; OS: overall survival; PFS: progression-free survival; PS: performance status