Is a 10 mm polyp considered large? In a screening population, cancerous polyps are uncommon. ... In the National Polyp Study, 610 mm and larger than 10 mm adenomas were 4.8 and 20.3 times more likely to have high-grade dysplasia compared with small adenomas, respectively (7)., You can Find A Cancer Hospital Please Join Here, Please join All Cancer Treatment Centers, Be sure to consult your doctor, Health Guide