According to the statistic reports from World Health Organization (WHO) International Agency for Research on Cancer (IARC), the incidence and mortality rate of colorectal cancer ranked third and fourth respectively among ten most commonly diagnosed cancer worldwide; moreover, based on the statistics from Health Promotion Administration, Ministry of Health and Welfare in Taiwan, the incidence and mortality rate of colorectal cancer ranked second and third respectively among call cancer in Taiwanese population. However, if colorectal cancer is diagnosed and treated in early phase, the 5-year survival rate for stage I colorectal cancer can be up to 90%; on the other hand, the 5-year survival rate for end stage colorectal cancer is only approximately 10%. Therefore, the screening, early diagnosis od colorectal cancer is crucial. To date, there are some known risk factors for colorectal cancer, including familial adenomatous polyposis, obesity, physical inactivity, etc. Alcohol had also been identified as an important risk factor for colorectal cancer, and the risk could be higher among Asian population because of the reduced enzymatic activity of some of the alcohol metabolizing enzymes. Thus, through this study, the investigators hope to find out the risk factors of colorectal cancer among Taiwanese population, including alcohol metabolizing enzyme gene polymorphisms and their interaction with environmental factors, to attain the purpose of early prevention of colorectal cancer.

The purpose of this study is to find out relationship between alcohol metabolizing enzyme gene polymorphism and colorectal cancer, and discuss the impact of the interaction between gene polymorphism and environmental factors on the risk of colorectal cancer.

Inclusion criteria:

Case:

• Histologically confirmed colorectal adenocarcinoma at National Taiwan University Hospital (NTUH) from 2000 to 2016
• Age >20 at the time of inclusion

Control:

• No diagnosis of colorectal cancer
• Age >20 at the time of inclusion
• Family members of case, including parents, siblings, offspring, spouse mother-in-law or daughter-in-law

Exclusion criteria (Both for case and control):

• History of familial adenomatous polyposis
• History of partial or total removal of the colorectum
• History of inflammatory bowl disease
• History of malignant neoplasms

primary care clinic visit at National Taiwan University Hospital