Individuals with hereditary non-polyposis colorectal cancer (HNPCC)
have a high risk of colorectal cancer (CRC). The benefits
of colonic surveillance in Lynch
syndrome and Amsterdam-positive (familial CRC type X familial colorectal
cancer type X (FCCTX))
families are clear; only the
interval between colonoscopies is debated.
The potential benefits for
families not fulfilling
the Amsterdam criteria are
uncertain. The aim of this study was to compare the outcome of colonic
surveillance in different
hereditary subgroups and to evaluate
the surveillance programmes.
Methods A prospective, observational study on the outcome of colonic surveillance in different hereditary subgroups based on 24 years
of surveillance data from the national Danish HNPCC register.
analysed 13 444 surveillance sessions, including 8768 incidence
sessions and 20 450 years of follow-up. CRC was more incident
in the Lynch subgroup (2.0%) than in
any other subgroup (0.0–0.4%, p<0.0001), but the incidence of
advanced adenoma did not
differ between the Lynch (3.6%) and
non-Lynch (2.3–3.9%, p=0.28) subgroups. Non-Lynch Amsterdam-positive and
families were similar in their CRC
(0.1–0.4%, p=0.072), advanced adenoma (2.3–3.3%, p=0.32) and simple
p=0.43) incidence. In moderate-risk
families, no CRC and only one advanced adenoma was found.
ConclusionsThe risk of CRC in Lynch families is considerable, despite biannual
surveillance. We suggest less frequent and more individualised
surveillance in non-Lynch families.
Individuals from families with a strong history of CRC could be offered
colonoscopies (unless findings at
the preceding surveillance session indicate shorter interval) and
individuals from moderate-risk
families could be handled with the
population-based screening programme for CRC after an initial