Background and study aims: To assess whether polyp histological type can be predicted by patient characteristics and endoscopic polyp findings.
Patients and methods: 1681 polyps in 494 patients were categorized as advanced adenomas (villous component or severe dysplasia or early cancer) or insignificant polyps. Chi-squared tests were used to analyze whether polyp histological type could be predicted based on patient age (< 60 vs. > or = 60 years), gender, family history of colon polyps or cancer, presence of anemia, polyp size (< or = 5 mm vs. > 10 mm), and location (left- vs. right-sided).
Results: Insignificant polyp histology (n = 1337) correlated with patient age < 60 years (P = 0.0026), lack of anemia (P< 0.0001), polyp size < or = 5 mm (P < 0.0001), and right-sided location (P= 0.0058). Stepwise inclusion of these parameters demonstrated that the association of a < or = 5 mm right-sided polyp in a patient < 60 years yielded the highest combined predictive value (96.2%) for an insignificant polyp. Conversely, age > or = 60 years, presence of anemia, polyp size > 10 mm, or left-sided location, as single or combined parameters, demonstrated a maximum predictive value of only 75.4% for an advanced adenoma.
Conclusions: A small right-sided polyp in a young patient is associated with a small risk (3.8 %) for advanced adenomatous tissue, indicating that histological investigation of such a polyp might not always be necessary. However, the recent recognition of flat adenomas and "mini" de novo colon carcinomas in the European population also may limit the usefulness of small polyp diameters in the exclusion of severe polyp histology.