Aim: Colorectal cancer (CRC) is a common disease in the older population, but it has become increasingly evident that it is also not infrequent in the young. The aim of this study was to describe the epidemiological, clinical and pathological characteristics of CRC in young Cambodians.
Methods: We examined clinical and pathological data from all CRC cases registered in the two reference centres for gastrointestinal tumours in Cambodia between 2005-2010. Age-specific CRC incidence rates were computed using the national population census 2008 data from the National Institute of Statistics. We compared differences in distribution of tumour location, histology, differentiation and UICC/TNM stage in two age groups, namely < 40 and ≥ 40.
Results: During this period, there were 356 new CRC cases, of which 29.8% affected patients younger than 40. This proportion is the second highest in the world, with a higher proportion only reported in Egyptian population. The crude incidence was 2.82 and 2.36 per 100,000 in females and males, respectively. Adenocarcinoma was the most common histologic type, and >50% of all tumours occurred in the colon, with no appreciable variation between the two age groups. Mucin-producing and advanced-grade tumours were twice more frequent in the young.
Conclusion: The unusually high CRC proportion in the young in our study could be due to referral bias. Nevertheless, together with the continuous exposure to hazardous environmental agents and the prevalent consanguinity in Cambodia, this question warrants further research to advance our understanding of CRC risk factors and perhaps genetic-environmental interactions in CRC epidemiology in young adults.