Background and study aims: Current surveillance guidelines risk stratify patients with adenoma by using only
one or two factors: adenoma multiplicity or presence of an advanced adenoma characteristic.
Combinations of adenoma characteristics are not considered, which limits the predictive
value of these guidelines. The aim of the study was to develop a scoring system for
more refined risk stratification of patients with adenoma.
Patients and methods: The Dutch Pathology Registry (PALGA) was used to identify newly diagnosed patients
with adenoma in 10 Dutch hospitals between 1988 and 2002. Medical records were reviewed
until 1 December 2008 for follow-up. Logistic regression analysis was used to assess
patient- and adenoma-related predictors of metachronous advanced neoplasia. The prediction
model was validated by bootstrapping and cross-validation. A score chart was developed
based on identified adenoma-related predictors. The discriminative ability of the
prediction model was compared with currently used risk stratifications in surveillance
guidelines.
Results: A total of 2914 patients with adenoma were included (mean age 61 years; 55 % male).
The score chart consisted of characteristics that contributed 1 point (size ≥ 10 mm,
villous histology, proximal location, having 2 – 4 adenomas) or 2 points (having ≥ 5
adenomas). A patient’s adenoma risk score could range from 0 to 5 points. A score
of 5 for a 75-year-old man implied a 5-year risk of advanced neoplasia of 46 %. The
discriminative ability of the model was moderate (c-statistic 0.712) but better than
risk stratifications in current international guidelines, which had c-statistics of
0.642 – 0.674.
Conclusion: A score chart that combines adenoma-related predictors of advanced colorectal neoplasia
optimized the risk stratification of patients with adenoma for appropriate surveillance
colonoscopy intervals.