Doctor's Insight.

The risk of colorectal cancer gradually increases with age.

And that's not all.

In 2017, the National Cancer Center published a list assessing factors related to cancer risk and prevention, which was revised in November 2020.

According to the list, they are starting to find the risk factors for colorectal cancer.

Hello and welcome to Doctor's Insight.

Latest research has shown that, while some lifestyle habits increase the risk of colorectal cancer, others can effectively reduce the risk.

Today, we will discuss lifestyle habits that can help prevent colorectal cancer and its recurrence.

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.

I'm happy to be back.

Today, we'll be discussing lifestyle habits that prevent colorectal cancer.

Can you tell us more about such research?

Reports show that it's "convincing" or "probable" that some lifestyle habits are linked to cancer.

They are hopeful that avoiding such habits will lead to cancer prevention for many people.

Improving lifestyle habits is also important
for preventing cancer recurrence.

For cancer survivors, it's one of the most essential parts of their treatment.

Alcohol consumption, smoking, and obesity are thought to increase the risk of developing colorectal cancer worldwide.

Also, it is thought that a risk factor that's unique to colorectal cancer is eating too much meat.

But not all types of meat.

Processed meat, such as ham and sausages, and red meat, such as beef, pork and lamb are considered "possible" to increase the risk.

Here is a list of factors that increase the risk of colorectal cancer.

The first one that is of particular concern is alcohol consumption, which shows "convincing" on the chart.

Can you tell us how alcohol is related?

When alcohol enters the body, some of it turns into a substance called acetaldehyde.

It is a carcinogen.

It's shown to be "convincing" in organs such as the esophagus, liver and colorectum, in which alcohol passes through.

So are you saying that we are enjoying alcohol when it is proven to cause cancer?

It depends on the extent you drink, and it's hard to say that "such amount" will or will not cause cancer.

Right.

However, various studies around the world have shown that the higher the average daily alcohol consumption, the higher the risk of cancer.

The alcohol consumption guidelines differ by country, but in general, the daily maximum intake recommended for men averages around 20 grams of alcohol per day.

Generally speaking, 20 grams of alcohol would be 500 milliliters of beer, a double shot of whiskey,

a little less than 2 glasses of wine, or 180 milliliters of Japanese sake.

Women tend to have less tolerance to alcohol than men, and in many cases, the maximum is limited to half the amount.

However, drinking is not recommended for anyone that's sensitive to alcohol.

It could cause damage to the body if you have low alcohol tolerance.

Lightweight drinkers and those who experience facial flushing need be cautious.

Now, let's move on to smoking.

How much does smoking increase the risk of colorectal cancer?

For example, a report comparing smokers and non-smokers in Japan found that the risk of developing colorectal cancer for men was 1.2 times higher than in non-smokers.

For women, the risk was 1.09 times higher.

So smoking can't be good?

When you quit smoking, it is thought to reduce the risk to 2/3 or less.

It says here that BMI is associated with the increased risk of colorectal cancer.

In other words, obesity is related to the disease.

Exactly.

To prevent cancer, it is better to be lean than obese, but there are some pitfalls to that.

Let's take a look at this video.

Here are some tips for improving health literacy as a patient.

Let's take a look at the following case.

Can you identify the pitfall?

We found a polyp in your colon, and although it was benign, we removed it, just to be safe.

Let's talk about improving your lifestyle habits to avoid colon cancer in the future.

Okay.

What do I have to watch out for?

Well, people who drink alcohol, smoke, or are obese have a particularly high risk.

Yeah, I guess I have to do something about my weight.

And also, come in for your regular screenings.

After the doctor's visit, the patient made continuous efforts to lose weight.

Now that I've lost all this weight, I don't need to worry about colon cancer.

10 years passed without undergoing regular screening.

I'm sorry to say, but you have cancer in your colon.

It seems that you've lost too much weight.

I can't believe it!

The fact is... being "too underweight" also increases the risk of cancer.

A study on Japanese people, often characterized as relatively thin, showed an increased risk of cancer.

It was seen especially among men, middle-aged and older, who were underweight, with a BMI of less than 21.

A BMI below 21 would be, for example, a person who is 170 centimeters tall and weighs less than 61 kilograms.

Being too skinny, in other words, malnutrition, is believed to be a factor in the development of cancer.

To prevent cancer, it is recommended not to be obese or too underweight.

As a rough guideline for BMI, it is important not to fall far outside the range of 21-25.

It showed to be "probable" that physical activity reduces the risk of colorectal cancer.

Yes, "probable" in this case is referring to colon cancer.

Among the various organs susceptible to cancer, colon is the only organ that hangs loosely.

Thus, it is believed that physical stimulation, easily caused by exercise, may be related to the prevention of cancer.

That's really interesting.

What kind of exercise do you recommend for preventing colorectal cancer?

For instance, walking 60 minutes every day would be effective.

In addition to that, it is recommended to do more strenuous exercises, that'll make you huff and puff.

The recommended amount is 60 minutes per week or more.

I see.

For colorectal cancer, it's considered "possible" that nutrients such as dietary fiber, calcium and unsaturated fatty acid can help prevent the disease.

Foods that are high in fiber include vegetables, fruit, potatoes, beans, seaweed and mushrooms.

Dairy products and spinach are high in calcium.

Unsaturated fatty acid is typically found in fish.

However, patients who have had colorectal cancer and undergone surgery, are often instructed to avoid dietary fiber, as it can aggravate your colorectum.

Oh, really?

Please make sure to follow the instructions given by your physician or dietitian regarding how to eat.

We should be aware that colorectal cancer could affect any of us, and put to practice the preventative measures we learned today.

I shared various lifestyle habits that help reduce the risk of colorectal cancer.

However, they are all generally considered to be ways for maintaining good health.

If you consider each of them, it's not so difficult.

You don't need to do them all at once, but just make it a habit, one at a time.

- Dr. Yoshino, thank you so much for being on our show.
- It was great a pleasure. Thank you.

- It's great to have you here. Thank you.
- Thank you.