Colorectal cancer: introduction

In Scotland, after lung cancer, and prostate cancer, colorectal cancer is the third most commonly diagnosed cancer in men and the third most common in women after breast cancer, and lung cancer (this excludes non-melanoma skin cancer).  In 2015, 1,975 men and 1,696 women were diagnosed with colorectal cancer in Scotland.  It is the third most common cause of death from cancer in men after lung and prostate cancer, and the third most common in women after lung and breast cancer. Relative survival has improved over recent decades, with 60.4% of patients now surviving to five years after diagnosis.

The main risk factors for colorectal cancer are: Diet (vegetables and fibre are probably protective while red meat and processed meats may increase risk), obesity, lack of physical activity, alcohol, genetic, and (probably) long-term smoking (SIGN126, 2011 (1.6Mb)).

Incidence rates of colorectal cancer increased in Scotland between the mid-1970s and the mid-late 1990s (Gray et al, 2002), but more recent data suggest that incidence rates are now decreasing.

Randomised controlled trials carried out in Minnesota, USA; Funen, Denmark; and Nottingham, UK have shown that it is possible to reduce mortality from colorectal cancer by screening based on faecal occult blood testing (FOBt). Pilot studies carried out in Grampian, Tayside, and Fife, and in parts of West Midlands have demonstrated that screening with FOBt is feasible in the UK, and that it should reduce deaths from colorectal cancer.  The Scottish Bowel Screening Programme has been a national programme since December 2009.