Aetiology
A high intake of meat and dietary fat can
increase the risk of colorectal cancer. Other
modifiable risk factors include smoking,
high alcohol consumption, lack of physical activity and a high body mass index.
Increasing evidence shows that lifestyle
changes such as quitting smoking and
losing excess weight can reduce the risk of
developing the disease (WCRF, 2007).
Some risk factors for colorectal cancer,
however, cannot be modified; these
include age and hereditary factors.
Colorectal cancer is strongly linked to
advancing age – 86% of cases arise in people
aged 60 years or more (CRUK, 2011). Three-
quarters of cancers occur by chance so,
although its high prevalence means many
people will have a family member who is
affected, only 5-10% of cases are a result of
recognised hereditary conditions.
Examples of germline mutations include
hereditary non-polyposis colorectal cancer
(HNPCC), which accounts for 5% of all olorectal cancers, and familial adenomatous polyposis (FAP), which accounts for 1%
(Burgess, 2005). Individuals diagnosed with
a previous colorectal cancer or with long-
standing ulcerative colitis are also at
increased risk of developing the disease and
need endoscopic surveillance