What happens if a doctor finds cancer during my colonoscopy?

Most colonoscopies end with a gastroenterologist saying to come back in 10 years for another colorectal cancer screening, a woozy ride home with a friend or relative, and an afternoon spent relaxing while the mild sedation wears off.

But what if a doctor finds cancer during your colonoscopy? What happens then? And, is there ever a chance you could wake up from a colonoscopy to discover you now have an ostomy? 

We checked in with colorectal cancer surgeon Abhineet Uppal, M.D.

No surgery or additional procedures will be performed during your colonoscopy

Some people worry that if their doctor finds any type of cancer during a colonoscopy, the procedure could suddenly morph into a major surgery — and they won’t get the chance to weigh in before something irreversible is done to them. But that’s not how doctors — or colonoscopies — work.

“Less than 1% of colonoscopies result in a finding of cancer,” says Uppal. “But even if yours is one of them, no one is going to perform an unplanned procedure on you while you’re sedated. Sometimes, we might have to stop the colonoscopy because there’s too much stool present for us to see things clearly. Or, we might not be able to advance the scope completely because a tumor or some other obstruction is in the way.”

In the case of too much stool, the colonoscopy would simply be rescheduled, and you’d be asked to repeat the bowel prep routine so your large intestine is clean enough for the doctor to see its walls through the scope lens.

If a blockage prevents your doctor from examining the entire colon, though, you’ll need additional scans and possibly exploratory surgery to determine the full extent of your disease.

Either way, notes Uppal, you’d be awakened and given time to process what you were being told before any surgery was performed.

“Even if your bowel was completely obstructed and you needed immediate relief to prevent a rupture, we wouldn’t go straight into surgery without discussing it with you,” Uppal adds.

Here are the steps that will happen if your doctor finds anything suspicious.

Step #1: Analyzing tissue samples: benign or malignant?

If a doctor does find anything suspicious during your colonoscopy, the first thing they’ll do is take tissue samples of it and send them off to a lab for a biopsy. That’s because not all abnormal colon growths are cause for concern.

“A pathologist will look at the cells under a microscope and let us know if they’re benign, pre-cancerous or cancerous,” explains Uppal. “That process takes at least a couple of days.”

Step #2: Determining the cancer type and stage

If a pathologist confirms that cancer cells are present, the next step is determining what type they are, and how much they have spread, if at all.

“Anal and rectal cancers are treated much differently than colon cancer,” notes Uppal. “With colon cancer, the first step is usually surgery, assuming the cancer hasn’t metastasized. But anal and rectal cancers usually start with either chemotherapy or radiation therapy first, followed by surgery later on.”

Once the cancer type has been identified, patients will have additional scans to determine the full extent of their disease. Then, they’ll meet with a surgeon to discuss possible treatment plans.

“Some people worry that if we wait to treat their cancer, it could spread while we’re still deciding what to do,” Uppal says. “But these tumors are not fast-growing. So, there’s plenty of time to sort out the best possible treatment plan for you. To be clear: surgery is not unimportant, but other therapies might be equally important. That’s why it’s so critical to get an accurate diagnosis.”

Step #3: Formulating a cancer treatment plan

Once your doctors have an accurate cancer diagnosis, they can start formulating a treatment plan for you.

“Some people assume that late-stage cancers are inoperable. But that’s not true,” explains Uppal. “Even if your cancer is at stage IV, you may still be able to undergo surgery.” 

Rectal cancer in particular requires a highly specialized surgeon, notes Uppal. That’s why it’s essential to go to a comprehensive cancer hospital like MD Anderson, where surgeons are not only very familiar with your exact disease but also have extensive experience in treating it.

“It’s just like our billboards say: ‘Where you go first matters,’” explains Uppal. “At MD Anderson, our colorectal group especially has shown that the quality of surgery plays a critical role in your overall risk of recurrence. It’s also crucial to ensuring that patients have the best possible outcomes, including quality of life after treatment.” 

Colonoscopies don’t spread cancer

Regardless of what doctors may find during your colonoscopy, you can rest easy knowing that the procedure won’t spread any cancer that may be present. 

“None of the procedures we perform spread cancer,” says Uppal. “That's true for both the colonoscopies we use to find cancer and the surgeries we perform to remove it.”

Request an appointment at MD Anderson online or by calling 1-877-632-6789.