A population-based study of age-related variation in clinicopathological features, molecular markers and outcome from colorectal cancer

Background: To investigate age-related differences in clinicopathological features, molecular alterations and patient survival in a large, population -based series of CRC. Patients and Methods: The study cohort consisted of 5,971 cases diagnosed between 1993 and 2003 representing over 90% of the CRCs diagnosed in the state of Western Australia. Results: Patients aged <= 30, <= 40, <= 50 and <= 60 years comprised 0.9%, 3.1%, 10.6% and 27.8% of all cases, respectively. The proportion of rectal cancers and tumors with poor differentiation was higher in <= 30-year-old patients and decreased progressively with age. The incidence of tumors with microsatellite instability was significantly higher inpatients aged <= 40 years (18.3%) compared to those aged 41-60 years (6.6%; p < 0.0001). TP53 mutations were also more frequent (p=0.002), however K-ras mutations were less common (p = 0.0001) when comparing the same age groups. Conclusion: These results provide evidence for major age-related differences in the clinical and molecular features of CRC.