For individuals with 1–2 small (<1 cm) low-risk colorectal adenomas, international guidelines range from no surveillance to offering surveillance colonoscopy in 5–10 years.
Dr Maria Elena Martinez and colleagues from California, USA hypothesised that the risks for metachronous advanced neoplasia among patients with low-risk adenomas differ based on clinical factors distinct from those currently used.
The researchers pooled data from seven prospective studies to assess the risk of metachronous advanced neoplasia.
The team defined 2 groups with 1–2 small adenomas based on guidelines from the UK or the European Union.
The research team found that absolute risk of metachronous advanced neoplasia ranged from a low of 3% to a high of 12%, depending on specific risk factor and guideline used.
|Absolute risk of metachronous advanced neoplasia ranged from a low of 3% to a high of 12%|
For the UK group, the highest absolute risks for metachronous advanced neoplasia were found among individuals with a history of prior polyp, villous histology, age ≥70 years, high-grade dysplasia, any proximal adenoma, distal and proximal adenoma or 2 adenomas.
For the EU/US group, the team noted that the highest absolute risks for metachronous advanced neoplasia were among individuals with a history of prior polyp or the presence of both proximal and distal adenomas.
The researchers observed strong associations for increasing age, and history of prior polyps and odds of metachronous advanced neoplasia were observed, whereas more modest associations were shown for baseline proximal adenomas and those with villous features.
Dr Martinez's team comments, "Risks of metachronous advanced neoplasia among individuals with 1–2 small adenomas vary according to readily available clinical characteristics."
"These characteristics may be considered for recommending colonoscopy surveillance and require further investigation."