Doctor's Insight.

Among different types of cancer, colorectal cancer cases have been increasing significantly around the world.

The number of people developing colorectal cancer worldwide has increased from an estimated 1.02 million per year in 2002 to 1.8 million per year in 2018,

which means that the number of new patients per year has gone up 1.7 times in 16 years.

Colorectal cancer is the most common form of cancer in Japan.

The most important key to saving lives is colorectal cancer screening, which involves examining stool samples.

In Japan, anyone over the age of 40 can undergo this test.

Today, we'll discuss testing methods that can lead to the early detection of colorectal cancer.

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 so much for joining us today.

Thank you for having me.

Today, we're focusing on colorectal cancer screening.

Is it necessary to get screened if we want to protect ourselves from colorectal cancer?

Yes. With advanced colorectal cancer, the patient may experience rapid weight loss and visible bloody stools, but most people do not develop noticeable symptoms until the disease has progressed.

Also, it is likely to develop after the age of 50.

I see.

For these reasons, it's recommended in developed countries such as the United States, European countries and Japan, that people undergo regular colorectal cancer screening starting around 40 to 50 years old.

So this means that getting tested is especially important for early detection and treatment?

Yes.

In the U.S., for example, the number of people dying from colorectal cancer is much lower than before.

A major reason for this is the increase in colorectal cancer screening rates.

According to statistics, the screening rate was 38% in the year 2000, but rose to 67% in 2018.

Quite increase.

Looking at the death rate from colorectal cancer in men, it is less than eight deaths per 100,000 people in the U.S.,

whereas in Japan, it is more than 10 deaths per 100,000 people.

In the U.S., both the number of patients and deaths have decreased.

But, can you explain why this is?

It was the introduction of "endoscopy," a procedure using a camera to look inside the body, for colorectal cancer screening.

People over the age of 50 can get either an endoscopy once every 5 to 10 years or a stool test that checks for blood once a year, at no cost.

I see.

An endoscopy can detect colorectal polyps before they develop into cancers.

Since polyps can be removed and treated, colorectal cancer cases have greatly reduced.

So endoscopies are useful for early detection.

How about in Japan?

Do people regularly get tested for colorectal cancer?

Is it the common thing?

In Japan, we conduct what's called "fecal occult blood test" to check for presence of blood in the stool as part of the colorectal cancer screening.

It is recommended that people over 40 years old take this test once a year.

If it comes back positive, the patient then undergoes an endoscopy as a follow-up test.

Oh, I see.

The screening rate in Japan was at the 20% level in 2010, but in 2019, it had increased to 48% for men and 41% for women, but the number is still low.

It is thought to be even lower now due to the reluctance to get tested because of the pandemic.

The number was in the 40% range even before the pandemic.

This seems pretty low, but what is the reason for the low rate?

According to different surveys, the low screening rate in Japan is due to the following reasons: People don't think they will get cancer.

They think screening is for those who have symptoms.

And people assume they're okay, because they've taken the test before.

But, these are all misconceptions.

I imagine that it's easy for us not to think of these things especially when we don't have symptoms, but can you please explain each of them?

Yes. One in two people in Japan will develop cancer at least once in their lifetime.

And by the time symptoms appear, the disease is already advanced and cannot be completely cured.

The risk of developing colorectal cancer increases with age, so we need to get screened regularly.

As a start, you should get a stool test when you reach the age of 40.

Can a person tell if they have colorectal cancer by taking the "fecal occult blood test?"

If, in fact, a person has colorectal cancer, it causes colonic bleeding, and blood will be present in the stools.

That's why the "fecal occult blood test" can lead to the early detection of cancer at a high rate.

If it's early stage, it can be cured almost 100%.

Now, let's find out how to do a fecal occult blood test.

First, obtain a fecal occult blood test kit from a medical institution or a laboratory.

The kit contains two containers and floating paper.

The sampling stick is attached to the lid.

Next, place the paper in the toilet bowl so that it floats on clean water.

After passing stool on top of the sheet, scratch the surface of the stool lightly with the sampling stick.

It's important to scrape the surface in several places.

Leave the sheet in the toilet bowl and flush.

The paper is soluble.

Put the stick back into the container and close.

Keep the container in a dark cool place.

Bring your stool sample to your healthcare provider during your next visit or send it to a designated lab.

Doctor, why are there two collection containers?

Is one a spare?

It is standard to collect stool samples for two days.

Oh, I see.

The detection rate of cancer with a one-day stool sample is about 45%, but increases to about 70% with samples taken from two different days.

When this is done two years in a row, with a total of four stool samples, the detection rate is 91%.

When you do it three years in a row, it's close to 100%.

By increasing the detection rate, most colorectal cancer can be found at an early stage.

Collecting two stool samples every year is important and effective.

If the test comes out positive, there is a possibility of having colorectal cancer, so a follow up test, in other words, an endoscopy, is recommended for definitive diagnosis.

Do all the people who test positive go for a follow-up test?

This is another major issue.

In Japan, about 30% of those who test positive do not go in for a follow-up.

Oh, really?

This number really stands out compared to other major types of cancer.

What's the reason for this?

Many people assume that the bleeding is caused by hemorrhoids.

With hemorrhoids, bleeding occurs around the anus, so blood is found just slightly on the surface of the stool.

It's unlikely that this will lead to a positive result using the test kit.

With colorectal cancer on the other hand, blood is likely to be detected with the test kit because it's often mixed in with the stool.

People should not assume that a positive result is caused by hemorrhoids, but suspect the possibility of colorectal polyps or cancer and take a follow up test.

That's a really important point.

Also of concern is the impact COVID-19 has on the low screening rate.

What are your thoughts on this?

If a person develops colorectal cancer but misses the opportunity of one annual screening, he or she will be left untreated for two years.

As a result, they may not be able to cure cancer that could have been eradicated.

I urge people to take protective measures against COVID-19 and go in for a checkup.

What would you say to those who are relatively young, say, in their 40's who are thinking about putting off their screening?

Colorectal cancer is the third most common cancer in the world and affects many of us.

After the age of 40, make sure to start paying attention to your health.

Getting colorectal cancer screening regularly offers peace of mind and allows early detection.

Dr. Yoshino, thank you so much for your time today.

Thank you.