Extremes of Age Versus Middle Decades of Life: A Population‐Based Analysis of Colorectal Cancer Survival in Queensland, Australia

Introduction Colorectal cancer (CRC) may behave differently depending on the patient's age at diagnosis. This study evaluated the effect of decade of life at diagnosis on the five‐year cancer‐specific and the five‐year stage‐specific survivals (5YCSS and 5YSSS, respectively). The authors hypothesised that both 5YCSS and 5YSSS would be poorer at extremes of age (EoA) compared to middle decades of life (MDoL). Methods Data was sourced from Queensland Oncology Repository (QOR) and held by Cancer Alliance Queensland. Patients diagnosed between 01 January 2001 and 31 December 2021 were allocated into 10‐year age groups and survivals were compared. Descriptive statistics, Pearson chi‐square, Cox regression analysis, logistic regression, and Cramer's V were used. A p ‐value < 0.05 was considered significant. Results Out of 56 768 patients, 44 836 were included in the 5YCSS analysis and 29 906 were included in the 5YSSS analysis. The highest 5YCSS of 74.20% belonged to patients 50–59 years, who were selected as the reference group. In comparison, patients under 30 years had a lower 5YCSS of 66.22% ( p < 0.005) and patients older than 80 years had the lowest 5YCSS of 58.78% ( p < 0.001). Over 80 years and under 30 years Stage IV patients had the lowest 5YSSS of 3.57% and 15.87%, respectively. Conclusion Patients diagnosed at EoA had a poorer 5YCSS compared to patients diagnosed in MDoL. Stage IV patients at EoA had poorer 5YSSS compared to patients in MDoL. This finding may be a result of more aggressive behaviour of CRC in young patients, within each stage, and increased frailty and comorbidity in older patients.