Introduction. Forty percent of newly diagnosed colorectal cancer (CRC) patients are aged over 75 years. However, often elderly patients are underrepresented in clinical trials; resulting in limited evidence based data to assist clinicians in making clinical decisions. Investigating drug deliverance in real world populations is vital in the extrapolation of clinical trial data to the diverse CRC real world population.
Aims. This study aimed to investigate the effect of patient age on quality use of medicine and outcomes using a linked dataset of real world stage IV CRC patients.
Methods. Records from Queensland’s CHARM oncology prescribing database were linked to external QLD health data collections from four hospital sites between 2009 and 2018. Statistical analysis was used to investigate relationships between patient age and the prediction of drug utilisation and survival.
Results. 25% of the 589 mCRC patients were aged ≥ 75 years. Elderly patients recorded a comparable overall survival (OS) when compared with young counterparts (17.9 vs 22.3 months, p=0.292). Patients aged ≥ 75 years were less likely to receive beneficial triplet-therapy as first line therapy when compared to younger patients (16 vs 38%, p<0.0001). Elderly patients were also more likely to be dose reduced at the initiation of first line treatment compared to younger counterparts (65 vs 31%, p<0.0001). Within the elderly cohort, such dose reduced patients and those dosed appropriately reported comparable OS outcomes (18.1 vs 15.9 months, p=0.796). Dose reduced elderly patients were however significantly less likely to experience therapy de-escalation (13 vs 29 %, p=0.036) and less likely to experience a dose reducing toxicity event throughout their first line of therapy (29 vs 57%, p=0.002).
Discussion. While age appeared to influence treatment selection and decision making, survival outcomes were found comparable between elderly and younger mCRC patients.