Colorectal Cancer #2: Endoscopic Diagnosis and Treatment

Doctor's Insight.

Hello and welcome to Doctor's Insight.

This is an endoscope used for diagnosing and treating colorectal cancer.

Roughly 90% of colonoscopes used throughout the world are made in Japan, and Japan is said to be a pioneer in the endoscopic treatment of colorectal cancer.

Diagnostic methods are also advancing.

In 2021, an AI system became available in Japan which instantly analyzes the images of the colorectum.

It is used to support the doctor with diagnosis and is gradually being adopted throughout the country.

However, some 30% of Japanese people who should be getting tested, do not undergo the endoscopic procedure.

What is the reason behind it?

And what is being done to address this issue?

Today, we'll look at the latest on endoscopic diagnosis and treatment.

Today's expert is Dr. Yoshino Takayuki, Deputy Director of the National Cancer Center Hospital East.

He is one of the world's leading physicians in colorectal cancer and has been involved in the development of numerous drugs.

Dr. Yoshino, thank you for joining us again today.

Thank you for having me.

Now, as it was mentioned, why is it that 30% of people in Japan who tested positive for blood in their stools do not undergo endoscopy?

The reasons vary, but common responses would be: They are embarrassed because the tube is inserted into the anus.

The procedure sounds painful.

They previously had an unpleasant experience using laxatives for an endoscopy.

However, improvements are being made to address such issues.

As you said, the endoscope is inserted through the anus, but is it safe?

Yes, the procedure is safe.

Today, I have with me a colonoscope.

Improvements have been made, and the ones being used currently are 11 to 13 millimeters in diameter.

As you can see, there's a camera at the tip.

And we can move it like this.

For patients who are truly afraid, many hospitals provide anesthesia, letting them to sleep through the procedure.

So let the doctor know in advance, if that's the case.

What does the inside of a colorectum look like?

The images of the rectum and colon are projected on a monitor.

This is a picture of an early-stage colon cancer.

The shape is more deformed compared to a polyp.

This one is about 8 mm in diameter.

I can understand that some people may feel embarrassed or maybe find it uneasy to use laxatives.

How are these issues being addressed?

During the endoscopy, your bottom will not be fully exposed.

You'll put on a trouser-type patient wear, which has a flap on the back that is opened only when inserting the endoscope.

Laxatives were unpopular, as people had to drink two liters of bad-tasting solution.

However, now, there are different flavors available.

Patients also drink less now;
one liter of laxative, followed by 500 milliliters of water.

There is also a system using AI to detect cancer.

Can you tell us more about it?

To be precise, it is called the "AI-assisted Endoscopic Diagnosis System."

AI instantaneously analyzes the images and shows where lesions, or polyps, that could become cancerous are located.

Here is a video where the system is being used.

It shows the endoscope passing through the rectum and colon and projecting the inner walls.

Notice that a section of the wall is instantly marked by lines.

This is how AI identifies the presence of a polyp.

And the numbers indicate the probability of it being a polyp.

So the AI does the job instead of the doctor?

No, it is only used to assist doctors with diagnosis.

The doctor makes the diagnosis with what the AI detects.

As doctors are human, it's possible that they miss a lesion due to fatigue or differences in their skills.

It is hoped that such occurrences will be minimized.

According to the developer, the system is able to detect raised polyps about 95% of the time, and flat polyps about 78% of the time.

As artificial intelligence enhances its ability through learning, its accuracy will continue to improve in the future.

If polyps or cancer are found during an endoscopy, how are they treated?

We remove polyps and early-stage cancer with the endoscope.

In many cases, treatment can be performed as part of the exam.

What does an early-stage cancer look like?

Let's take a look.

Colorectal cancer originates from inside the wall of the colon or rectum and penetrates deeper into the wall as it progresses.

Cancer is considered "early-stage" when it remains in the "mucosal layer" or in the "submucosal layer" just below.

In the early-stage, there is very little chance that the cancer has spread to other parts of the body.

It can be treated using an endoscope since the treatment only requires a small resection of the cancer and its surrounding area.

How do you treat early-stage cancer and polyps with an endoscope?

The tip of the endoscope has a camera plus a tiny hole.

A special instrument to remove the cancer comes out through here.

There are several types of instruments and methods.

And this here is called a snare.

The doctor loops the wire around the polyp or cancer.

Here is a video of a real procedure.

The snare tightens around the base of the cancer.

Next, high-voltage current is applied to the area to burn it off.

When the cancer is flat, the doctor injects saline solution to raise the tumor.

It is then burned with a snare or removed with an electric scalpel.

Early-stage cancer can be cured almost 100% with such treatments.

However, in some cases, a section of the colon may be adhered, making it difficult for the tube to pass through.

In such cases, there are mainly two testing options.

One is the "capsule endoscopy," which is a procedure using an 11 mm-diameter capsule with a built-in camera.

After swallowing the capsule, it passes through the colon and rectum while taking pictures.

The images are transmitted to a receiver and the capsule is excreted during a bowel movement.

This is an image taken with the capsule camera.

It has lower resolution compared to the images of a regular endoscopy.

The other method is called CT Colonography.

It uses CT scanning to produce a three-dimensional image of the colon as shown here.

The bulging area is the cancer.

This is a comparison of a regular endoscopic image and a CT Colonography image of the same cancer.

The image of cancer is reproduced very realistically through computer graphics.

If in case polyps or suspicious tumors are detected, patients will have to be examined with the conventional endoscopy procedure for definitive diagnosis.

You mentioned that endoscopic treatment can be performed for early-stage cancer, but how about for cancer that is more advanced?

For cancer that's found deeper than the layer of early-stage cancer, there is a chance that it has spread, even if the tumor is removed.

In that case, the patient will need to undergo surgery to remove a large area of the colon instead of an endoscopic treatment.

There is open surgery as well as laparoscopic surgery, in which the procedure is conducted through several small incisions.

And recently, robot-assisted laparoscopic surgery is also becoming available.

If no cancer is found away from the colorectum, there is a good chance that it can be cured with surgery.

However, it's still possible that cancer cells had already spread, leading to recurrence even after surgery.

Furthermore, with surgery, there are often side effects such as bowel and bladder problems and sexual dysfunction.

The most important thing is to undergo regular colorectal cancer screening, and if an endoscopy is recommended, be sure to get one.

Doing so will help detect and cure cancer in its early stages almost 100% of the time.

That's good to know.

Dr. Yoshino, thank you for being with us today.

My pleasure. Thank you for having me.