RESUMO
The incidence of inflammatory bowel disease (IBD) has been increasing in Southeast Asia (SEA) in tandem with its economic growth and urbanization over the past 2 decades. Specific characteristics of IBD in SEA are similar to East Asia and the West, such as the declining ratio of ulcerative colitis to Crohn's disease. However, exceptionally low familial aggregation is seen. Smoking is also not a common risk factor in patients with Crohn's disease. The incidence of perianal disease is higher in SEA than in Australia and is comparable to the West. In a multiracial population, such as Singapore and Malaysia, Indians have the highest incidence and prevalence rates, which are likely to be due to important putative mutations. For instance, a higher frequency of the NOD2 predisposing mutation SNP5 and IBD risk allele IGR2198a and IGR2092a were found in Indians. Although differences in the genetic constitution play an important role in the epidemiology and prognosis of IBD in SEA, the emergence of this disease offers a unique opportunity to identify potential exposomes that contribute to its pathogenesis.
RESUMO
BACKGROUND: While the world witnesses an increasing trend of young-onset colorectal cancer (CRC), the information regarding the impact of age on CRC is limited in Malaysia. This study aimed to compare the incidence, clinic-demographic profiles and survival rates of CRC between patients above and under 50 years of age in northern Malaysia. METHODS: This was a registry-based, cross-sectional study. All the CRC cases reported by 18 hospitals to the National Cancer Patient Registry - Colorectal Cancer (NCPR-CC) between January 2007 and December 2017 were included in the analysis. The patients were categorized by age into the above-50 and under-50 groups. The changes in the age-standardized incidence and mortality rates of both the age groups were determined using the time-series analysis, and the impact of age on the mortality risk was assessed using the Cox regression analysis. RESULTS: Of the 6,172 CRC patients enrolled in the NCPR-CC, 893 (14.5%) were in the under-50 group. As compared with their older counterparts, the patients in the under-50 group were more likely to be female, be of Malay ethnicity, be non-smokers, have a family history of CRC, and present late for treatment. The age-standardized incidence and mortality rates of CRC in the under-50 group remained stable over the years, while a decreasing trend was clearly seen in the mortality rates of CRC in the above-50 group (p=0.003). Nevertheless, the two age groups also did not differ in the mortality risk (adjusted hazards ratio: 1.10; 95% CI: 0.90, 1.36). CONCLUSION: Young-onset CRC constituted a considerable proportion of CRC cases in Malaysia. However, in contrast with the findings of most studies, it demonstrated neither an uptrend in age-standardized incidence rates nor a higher mortality risk. Our findings suggest the need to upscale and lower the recommended age for CRC screening in Malaysia.