Colorectal cancer is a major cause of cancerrelated deaths and the third most commonly diagnosed cancer worldwide.Current estimates indicate that 20-30% of those who undergo treatment will experience recurrence and 35% of all patients will die within 5 years.~The human colon plays host to a diverse and metabolically complex community of microorganisms. While the specific oral microbiome has been found to contribute to the development of colorectal cancer. Investigators speculate that specific oral microbiota related to colorectal cancer relapse after curative treatment.~Patients are routinely offered surveillance in order to detect disease recurrence at an early, asymptomatic stage, with the intention of improving survival. Nevertheless, controversy continues to surround the optimal surveillance protocols. Investigators aim to discover if any difference of oral microbiota is exist in patients who suffer from relapse compared with patients who do not.~Future surveillance after colorectal cancer treatment should focus on risk-stratification. Finally investigators will develop patient-centred programmes of surveillance protocols base on microbiota analysis.
Specific oral microbiome has been found to contribute to the development of colorectal cancer. We speculate that specific oral microbiota related to colorectal cancer relapse after curative treatment. This study aim to discover if any difference of oral microbiota exist in patients who suffer from cancer relapse compared with patients who do not. Finally develop patient-centred programmes of surveillance protocols base on microbiota analysis.