The majority of colorectal cancers arise from a non-malignant growth in the large intestine known as an adenoma. In the early stages these resemble a polyp.

However in some cases adenomas have the potential to increase in size and undergo a series of changes within the cells. This can result in the cells becoming abnormal in function, structure and shape. This is commonly referred to as malignancy or a cancer.

A Polyp

Cross Section
of Polyp

X Ray Film of colon