Colorectal cancer (CRC) is the second leading cause of cancer-related deaths with a lifetime risk of 80-100 per cent for each person worldwide. Approximately 1.4 million new cases of colorectal cancer were identified worldwide in 2012, comprising 10 per cent of all new cancer cases. Survival of colorectal cancer depends on the stage at which it is diagnosed, with worse survival in later-stage diagnoses. The five-year survival rate is 90% for diagnosed early-stage colorectal cancers, compared to 13% for those diagnosed late-stage. In terms of prevalence, colorectal cancer ranks fourth among males in frequency, with about 550 000 new cases worldwide a year, and seventh among females, with an estimated 473 000 new. Among males the agestandardized incidence is 20.1 per 100 000 a year and among females is 14.6. Mortality is roughly half that of about 530 000 deaths in 2002 (males, 280 000; females, 250 000). For an estimated 2.8 million people living within 5 years of diagnosis, colorectal cancer accounts for 11.5 per cent of all prevalent cancer cases , the second most prevalent cancer in males following prostate cancer (1 515 000 cases) and the third most prevalent cancer in females following breast and cervix uteri (1 315 000). The precise cause of colorectal cancer is not clear, although certain risk factors, including diet, cigarette use and heavy alcohol consumption, are strongly related to the disease. Individuals with other genetic cancer syndromes or a family history of colorectal cancer may have a high chance of developing the condition.
