During a colonoscopy, the doctor inserts a colonoscope into your rectum to check for abnormalities in your entire colon. A colonoscopy (koe-lun-OS-kuh-pee) is an exam used to look for changes — such as swollen, irritated tissues, polyps or cancer — in the large intestine (colon) and rectum.
A positive colonoscopy result indicates that your gastroenterologist found polyps or abnormal tissue that may indicate a cancer or a precancerous lesion. If polyps are found in the colon, your doctor will remove them and send them to a laboratory for additional testing.
Some polyps can develop into cancer if left untreated for a long time (usually at least 10 years). Screening is crucial for cancer detection because most colorectal cancers don't cause symptoms in the early stages. Many times, doctors first spot colon cancer during a routine screening colonoscopy.
Here's what we know: As often as 40% of the time, a precancerous polyp — frequently a type called an adenoma — is found during a screening colonoscopy. Colon cancer is found during only in about 40 out of 10,000 screening colonoscopies, Dr. Sand said.
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.
Care begins with cancer staging
During a colonoscopy, your doctor will remove polyps, abnormal growths in the colon that can become cancerous. If biopsy results show cancer, the next step would be imaging tests for diagnosing cancer. Imaging tests check whether the cancer has spread to any organ or lymph nodes.
The 3 main symptoms of bowel cancer are blood in the stools (faeces), a change in bowel habit, such as more frequent, looser stools, and abdominal (tummy) pain. However, these symptoms are very common.
However, it will take some time to receive your test results from the lab that will confirm or rule out cancer. Your doctor may have some information for you prior to the lab test results, but the official results will come from the lab within a couple weeks.
Most of the time a colonoscopy will not find anything to worry about. But it might help to speak to someone if you're feeling worried about your results.
Nearly all cases of colorectal cancer develop from polyps. They start in the inner lining of the colon and most often affect the left side of the colon and rectum. Detection and removal of polyps through colonoscopy reduces the risk of colorectal cancer.
Immediate treatment is needed to remove the blockage. This can relieve painful symptoms and prevent serious complications such as tissue death or rupture of the small bowel. Without treatment, a bowel obstruction can be fatal.
Thin stools are a sign of colon cancer. Any time you notice a narrow or ribbon-like stool, it indicates changes in your colon.
Colon cancer can cause bleeding in the digestive tract and make your stool a dark brown, maroon, or black.
Diarrhea: Caused by an overflow of intestinal fluid around a partial obstruction. Alternating constipation and diarrhea: A more telling sign of colon cancer. Blood in stool: Also known as hematochezia, which can be bright red if the tumor is near the rectum or dark red or maroon if higher up in the colon.
Some cancers (such as colon cancer) present with a dull ache in the lower belly, or lower back. For some, this may feel less like an obvious pain, and more like a discomfort. Bellyaches that persist should not be ignored, as they can be a warning sign of a more serious problem.
Because early stages of colon cancer can go unnoticed for years, screening is important for early detection. It is generally recommended that individuals at average risk for colon cancer receive a screening test every 10 years.
Myth: I don't need a colonoscopy because I'm not having any symptoms. Fact: Many people are diagnosed with colon cancer when they are feeling just fine. People don't think they can have colon cancer if they feel OK, but they most certainly can.
Cancer of the colon is a highly treatable and often curable disease when localized to the bowel. Surgery is the primary form of treatment and results in cure in approximately 50% of the patients. Recurrence following surgery is a major problem and is often the ultimate cause of death.
If you've been diagnosed with colon cancer, your doctor may recommend tests to determine the extent (stage) of your cancer. Staging helps determine what treatments are most appropriate for you. Staging tests may include imaging procedures such as abdominal, pelvic and chest CT scans.
Stage III adenocarcinoma of the colon is a common and curable cancer. Depending on the features of the cancer, 40-50% of patients are cured without evidence of cancer recurrence following treatment with surgery alone.
Colon cancer most often spreads to the liver, but it can also spread to other places like the lungs, brain, peritoneum (the lining of the abdominal cavity), or to distant lymph nodes. In most cases surgery is unlikely to cure these cancers.
This means cancer and polyps can sometimes go undetected. 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'.
In most cases, colon and rectal cancers grow slowly over many years. Most of those cancers start as a growth called a polyp.