I would say the vast majority of polyps will not become cancerous. But, it is too risky to leave it alone. For example, if I am doing a colonoscopy for a patient and I see a small lump, statistically speaking maybe that lump has 1-2% risk that, within 10 years, it will evolve to become cancerous.
But I can’t take that risk, so I will remove any small lumps. Having said that, not all polyps will progress to cancer, you cannot predict which will and won't when it is small and early.
