Ninety percent of cases occur after age 50, with males somewhat more likely to develop polyps than females; therefore, colon cancer screening is usually recommended starting at age 50 for both sexes. It takes approximately 10 years for a small polyp to develop into cancer.
Polyps in the colon or rectum
Some types of polyps can change into cancer over time (usually many years), but not all polyps become cancer. The chance of a polyp turning into cancer depends on the type of polyp it is. There are different types of polyps.
While the majority of colon cancers start as polyps, only 5-10% of all polyps will become cancerous. The size of a polyp typically does make a difference. The larger the polyp becomes, the bigger the risk of it developing into colon cancer.
Q: How long does it take for cancer to form on a colon polyp? A: Time is on your side when it comes to colorectal cancer forming in a polyp. The process is estimated to take 10 years — a period that leaves ample opportunity for early discovery and treatment.
Colon cancer, or cancer that begins in the lower part of the digestive tract, usually forms from a collection of benign (noncancerous) cells called an adenomatous polyp. Most of these polyps will not become malignant (cancerous), but some can slowly turn into cancer over the course of about 10-15 years.
So, despite having had a 'clear' colonoscopy, some patients go onto develop bowel cancer – referred to as post-colonoscopy colorectal cancer (PCCRC) or 'undetected cancer'. Not detecting a cancer in this way can lead to poorer outcomes for patients – the earlier the cancer is identified the more treatable it is.
Colon cancer is typically slow-growing, starting as a benign polyp that eventually becomes malignant. This process may occur over many years without producing any symptoms. Once colon cancer has developed, it may still be years before it is detected.
It takes approximately 10 years for a small polyp to develop into cancer. Family history and genetics — Polyps and colon cancer tend to run in families, suggesting that genetic factors are important in their development.
People who have had certain types of polyps removed during a colonoscopy. Most of these people will need to get a colonoscopy again after 3 years, but some people might need to get one earlier (or later) than 3 years, depending on the type, size, and number of polyps.
Not all polyps will turn into cancer, and it may take many years for a polyp to become cancerous. Anyone can develop colon and rectal polyps, but people with the following risk factors are more likely to do so: Age 45 years and older.
Surveillance refers to the process of evaluating patients with a personal history of polyps or cancer. People who have precancerous polyps completely removed should have a colonoscopy every 3-5 years, depending on the size and number of polyps found.
Polyp Growth Rates
Cancerous polyps tend to grow slowly. It is estimated that the polyp dwell time, the time needed for a small adenoma to transform into a cancer, may be on average 10 years (17). Evidence from the heyday of barium enema examinations indicates that most polyps do not grow or grow very slowly (18).
You should be screened regularly for polyps if: You're age 50 or older. You have risk factors, such as a family history of colon cancer. Some high-risk individuals should begin regular screening much earlier than age 50.
Patients aged 50 years or older were more likely to have sessile polyps (p=0.023) and polyps located in the proximal colon (p=0.009). There were no significant differences between groups in histopathology or presence of dysplasia.
They are not cancer, and most of them have not started to change into cancer. If you get them at the precancerous phase, they don't have a chance to grow and turn into cancer. But you will need to come back for follow-up testing to see if more polyps turn up in the future.
In most cases, no. Your doctor can't usually tell, simply by looking at a polyp during a colonoscopy, if it's cancerous. But if a polyp is found during your colonoscopy, your doctor will remove it and send it to a lab for a biopsy to check for cancerous or precancerous cells.
"Precancerous polyps are extremely common," he says. "We expect to find them in more than a quarter of the colonoscopies that we do at a minimum. So, you know, maybe a third or even a half of all patients getting [a] colonoscopy will have precancerous polyps."
Foods to limit
Research suggests that eating less of the following foods may have health benefits and may lower your chances of developing polyps: fatty foods, such as fried foods. red meat, such as beef and pork. processed meat, such as bacon, sausage, hot dogs, and lunch meats.
The presence of PTSD has a marked impact on colonoscopy rates in Australian veterans. The increased polypectomy rate independent of increased colonoscopy rate suggests that PTSD is a risk factor for colonic polyp formation.
The doctor will then send any removed polyps to a pathologist for a biopsy to see if cancer is present. If the biopsy reveals that cancer is present, then cancer specialists will outline a treatment plan for the person. Common treatments for colon cancer include surgery, chemotherapy, and radiotherapy.
Signs and symptoms
The 3 main symptoms of bowel cancer are blood in the stools (faeces), changes in bowel habit – such as more frequent, looser stools – and abdominal (tummy) pain. However, these symptoms are very common and most people with them do not have bowel cancer.
Age. The risk of colorectal cancer increases as people get older. Colorectal cancer can occur in young adults and teenagers, but the majority of colorectal cancers occur in people older than 50. For colon cancer, the average age at the time of diagnosis for men is 68 and for women is 72.
In most cases, colon and rectal cancers grow slowly over many years.