Over twelve years, fifty three of 397 (13.4%) patients treated at our centre comprised the young colorectal cancer group. Prevalence was comparable with most other reports from Asia; 10.1% in Taiwan , Istanbul 18% , another Sri Lankan report of 19.7% , and 23% in Saudi Arabia . Our figure was considerably more than that reported from the West; 2.8% in the United States , 3% in France  and 5.5% in New Zealand [6, 15]. The high percentage reported in developing countries may be due, in part, to the higher population of younger people in these countries.
Young patients with colorectal cancer may be diagnosed late due to low suspicion of malignancy in these patients . However, the duration of presentation did not seem to influence overall survival in this analysis and we are in agreement with Lin et al . The most common presenting symptom was alteration of bowel habit. Other symptoms were rectal bleeding, non-specific abdominal pain, tenesmus, anaemia, loss of appetite and weight. The majority were not obstructive lesions. Furthermore, in this study, the majority of young patient cancers were sporadic with a greater frequency in the colon compared with older patients. Synchronous cancers were to be found exclusively in young patients. Hence, young patients of Asian origin, who present with these symptoms, should be investigated without delay to exclude malignancy.
Our study showed that a majority of young patients had adenocarcinoma without a mucinous component and, that about one in 5 were poorly differentiated, which was greater than in older patients. Mucinous and signet ring cell cancer comprised 16% of all colorectal cancers in the young. This differs from most other reports where mucinous, signet ring and poorly differentiated tumour comprised the majority of pathology [4, 10, 12, 17]. One study had both mucinous and signet ring cancer as the leading type . In general, mucinous and signet ring tumours have been associated with higher mortality compared with carcinoma without a mucin component.
In the young, predicted survival at five years was 70% and disease free survival was 66%. Our findings are in accordance with several previous reports which also includes a previous report by our group for survival in older patients with colorectal cancer [8, 12, 13] , where Kaplan Meier graphs for older patients have already been displayed and discussed . Unique, in this study, is that death from cancer in those less than 40 years occurred early, within twenty months of operation, which is different to cancer related death reported in those over 50 years in our previous report . In other words, those young patients who survived more than 20 months after operation were likely to live five years and more. Our data are different to previous reports, in which, overall five year survival rates, in young patients with colorectal cancer, were around 30% [10, 18]. Greater five year survival in our patients may be due to the smaller proportion of mucinous and signet ring tumours compared with a higher prevalence of mucin producing, high grade tumours reported in other studies.
Earlier AJCC stage and non-use of neo-adjuvant therapy in patients with rectal cancer seemed to bear significant survival benefit. The association between use of neo-adjuvant therapy for rectal cancer and poor survival may reflect aggressive tumour biology and later tumour stage rather than the beneficial effect of pre-operative chemoradiation on rectal cancer. Furthermore, although univariate analysis showed a positive resection margin to be associated with poor survival, The Weibull Hazard model analysis did not find this to be a significant independent prognostic factor. We may infer that a positive resection margin in colorectal cancer, given that the surgical procedure was performed with curative intent by a trained surgeon, was a summative co-factor in a biologically aggressive tumour.
In our analysis, other variables such as gender, tumour location, tumour characteristics - invasion margin (pushing vs. infiltrative), perineural and lymphovascular invasion - did not significantly influence overall survival. Limitations in the current study may be attributed to a small sample size in a single institution.