How Long Does It Take for Precancerous Polyps to Turn into Cancer?

Colorectal polyps are irregular tissue growths that protrude from mucous membranes on the lining of the large intestine (colon) or rectum. The types of polyps that may become cancerous include adenomatous polyps (adenomas), hyperplastic polyps, and sessile-serrated and traditional-serrated polyps.

Colorectal polyps are irregular tissue growths that protrude from mucous membranes on the lining of the large intestine (colon) or rectum. They may be flat or may appear to be attached by a stalk (pedunculated). Colon polyps are the most common type of polyp.

There are a few different types of polyps, some of which have the potential to become cancerous. 

Types of polyps that may become cancerous include:  

• Adenomatous polyps (adenomas)
• Hyperplastic polyps
• Sessile-serrated and traditional-serrated polyps

Colorectal polyps often have no symptoms. When symptoms occur, they may include:

• Blood in stool
• Diarrhea
• Constipation
• Changes in bowel habits
• Lower abdominal pain or discomfort
• Fatigue due to blood loss over time

Causes and risk factors for developing colorectal polyps include: 

• Age over 50
• Lifestyle 
  • High-fat diet
  • Diet high in red meat
  • Low-fiber diet
  • Smoking
  • Obesity
• Family history of polyps or colorectal cancer
• Inflammatory bowel disease
  • Ulcerative colitis
  • Crohn’s disease

In addition to a physical examination, colorectal polyps are often diagnosed during screening to check for colon or rectal cancer. 

Tests for colorectal polyps include: 

• Colonoscopy 
• Sigmoidoscopy 
• Computerized tomography (CT) colonography (also known as virtual colonoscopy) 
• Stool test 
• Capsule colonoscopy 
• Lower gastrointestinal series

A tissue sample (biopsy) may be taken of the colorectal polyp to determine if it is cancerous. 

Treatment for colorectal polyps involves removing them. This is usually done when they are found during a colonoscopy in order to eliminate the chance of them becoming cancerous. 

Surgical removal of colon polyps is called a polypectomy, which is performed through a colonoscope. 

About 2/3 of colon polyps are adenomas, which are polyps that may become cancerous.

It is believed to take about 10 years for an adenoma (precancerous polyp) to turn into cancer.

Because it takes such a long time for a polyp to become cancerous, colorectal cancer can often be prevented if precancerous polyps (such as adenomas) are detected and removed before they become cancerous (malignant). 

It’s not always possible to prevent colorectal polyps, but healthy lifestyle changes may help reduce the risk of developing some types of polys. 

• Exercise regularly
• Don’t smoke
• Avoid alcohol consumption
• Lose weight if you are overweight
• Take low-dose aspirin daily 
  • Talk to your doctor before doing this as aspirin may cause gastrointestinal bleeding
  • Children should not be given aspirin because it can cause Reye’s syndrome, a rare but serious illness