Report in English with a Dutch summary (KCE reports 45A)

KCE reports vol.45 Screening for Colorectal Cancer 47
Key messages
About 70-75% of patients with colorectal cancer have sporadic
disease, with no apparent evidence of having inherited the disorder.
The remaining 25-30% of patients has a family history of colorectal
cancer that suggests a genetic contribution, common exposures
among family members, or a combination of both.
Individuals with a family history of colorectal cancer are at
increased risk of developing colorectal cancer and targeted
screening should start earlier than 50 years in those subgroups. The
risk is greater when associated with early age of onset or multiple
affected relatives.
Approximately 5 to 6% of colorectal cancers will occur in individuals
that are to be considered at high hereditary risk for development of
colorectal cancer: HNPCC, FAP, AFAP, and variants.
A personal history of adenomatous polyps is associated with an
increased risk of future development of additional polyps and of
colorectal cancer. This risk increases with sizes greater than 1 cm
for any adenomatous polyp, the number of polyps, villous or
tubulovillous histology and grade of dysplasia.
Patients with resected colorectal cancer are at risk for recurrent
cancer and metachronous neoplasms in the colon.
Patients with a personal history of long standing active
inflammatory bowel disease involving the colon, such as longstanding
(8 - 10 years) chronic ulcerative colitis or Crohn s colitis
have a predisposition for colorectal cancer.