Colorectal Cancer #3: Drug Treatment

Doctor's Insight.

Every year, 1.8 million people develop colorectal cancer around the world.

It is the 3rd most common type of cancer.

This is a picture of colon polyp.

If left untreated, they can lead to colorectal cancer.

Polyps can develop into advanced cancer even within a few years.

As they cannot be surgically removed at that point, drugs become the preferred treatment option.

First, the cancer is genetically analyzed, and the doctor determines which drug is best suited for that type.

The most important drugs are molecular-targeted drugs, which are designed to attack only cancer cells.

In today's episode, we will feature the latest advances in drug treatment for colorectal cancer, that's making rapid progress.

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, we're happy to have you again today.

I'm happy to be here.

Today, we're focusing on drug treatment for colorectal cancer.

Dr. Yoshino, what are the latest advancements?

First of all, different types of drugs have come out.

When I became a doctor around 25 years ago, there were only two types of drugs for colorectal cancer.

Today, there are 22 different types that are mainly used.

This has made it easier to pick out the most effective drug for each patient.

From 2 types of drugs to 22 types.

That's quite an improvement.

Of those 22 drugs, I understand that you have been involved in the research for many of them.

Yes, our research group has conducted clinical trials on 17 of these drugs, on patients with colorectal cancer.

It has helped the drugs become available for practical use.

That's really great.

Have the drugs enhanced the efficacy of treatment?

Yes, compared to patients who don't receive any treatment, those who get treated with drugs live more than five times longer.

In the past, many people underwent drug treatment, because they could not be operated on, and there was no choice but to use drugs.

However, now, they can take drugs that are proven to be effective.

I want people to know that many patients are now using drug treatment with a more positive mindset.

Right, this is really all wonderful news.

I understand that molecular targeted drugs are key to the treatment.

Please tell us more about it.

Conventional anti-cancer drugs attack not only cancer cells, but also the normal cells surrounding them.

As a result, they are prone to cause serious side effects.

On the other hand, molecular targeted drugs attack only cancer cells.

That's why, the degree and frequency of side effects have been significantly reduced.

There are two types of molecular-targeted drugs used for colorectal cancer.

The first type is angiogenesis inhibitors.

Cancer cells form new small blood vessels around them, in order to take in nutrients and oxygen that help them grow.

This drug prevents the blood vessels from being formed.

In other words, the drug cuts off the cancer's supply lines.

The other type is anti-EGFR antibody drug.

EGFR is one of the receptors on the surface of cancer cells.

When proteins that cause cell growth attach to these receptors, the cancer becomes larger.

This drug attaches to the receptor before the protein does.

This is how it prevents cancer growth.

Does this mean that you know in advance which of these two types will be more effective?

Yes, cancer is caused by gene mutations in the cells.

We examine the genes in the cancer cells by removing a small piece of cancerous tissue.

Oh, I see.

In recent years, we can also do this with a blood test.

How is the tissue or blood examined?

With conventional genetic testing, we were only able to test for one type of gene mutation at a time.

However, in 2019, the practical application of "cancer multi-gene panel test" started in Japan.

By placing tissue on this high-speed analyzer known as the "next-generation sequencer", it allows us to examine more than 100 genes involved in hundreds of types of cancer at once.

Wow, that's amazing.

Currently, three testing methods are covered by insurance, one of which was developed specifically for a gene that is common among the Japanese.

Japan is very advanced in this field of research.

Using this "cancer multi-gene panel test," you can also find the genes involved in colorectal cancer?

Yes, six genes are currently known to be involved in the development and growth of colorectal cancer.

It's possible to identify which of these genes are mutated.

The results help determine the most effective type of drug and the combination of drugs.

That's really great to know.

Now, how does the cancer multi-gene panel test determine which drug is most suitable?

Let's find out.

The cancer multi-gene panel testing classifies colorectal cancer patients into 3 types.

This time, for the sake of clarity, we will refer to them as types A, B, and C.

For instance, in the case of East Asian patients, type A is estimated to account for 50%, type B for 6%, and type C for 44%.

Angiogenesis inhibitors are used for type A and B, while anti-EGFR antibody drugs are used for type C.

With the improvement of drug efficacy, there is a gradual increase in the number of cases where tumors are shrinking, making it possible to perform surgery.

How effective is the treatment compared to before?

Up until around the early 2000s, before the widespread use of molecular-targeted drugs, the median survival time for those who could not undergo surgery was about one year, even with drugs.

That's quite short.

The number had increased significantly to 30 months by 2015.

With the development of several new drugs since then, we believe it is now closer to three years.

Dr. Yoshino, how are the drugs administered?

Most are given by IV injections.

The conventional method of IV requires a hospital stay on a regular basis.

In many cases, patients are given an infusion once every two weeks for 48 hours.

Two whole days for IV... it's very time consuming, and I imagine it must be quite tough.

Recently, it has become possible to do this at home, or at work.

Oh, that's great.

First, a simple surgery is performed to implant a tube and an IV insertion port into the body.

This is a picture of an insertion port, which is often buried under the skin below the collarbone.

A patient goes to the hospital in the morning to have the IV needle inserted.

It is then connected to a "portable pump" like this one.

This can be worn around the neck or placed in the inside pocket of a jacket, allowing you to go to work, or go back home.

You can remove it yourself when the bag is empty.

The side effects from drug treatments are said to have reduced dramatically.

But, how have they improved?

Even now, there are some side effects in most cases.

However, many are mild cases.

For example, skin conditions and diarrhea are common, but they can be adequately treated with medications.

In the past, patients were often hospitalized and spent time in bed due to severe side effects during anticancer treatment.

Now, that's seen only in about 1 or 2 out of every 100 patients.

We've learned a lot today about the advances in drug treatment for colorectal cancer.

Patients who are being treated with drugs should continue their treatment, as they are not eligible for surgery.

Is that right?

Currently, several new drugs are being developed around the world.

And I am hopeful that, as we continue to treat cancer with current drugs, newer, more effective drugs will become available.

If you are getting treated for colorectal cancer, please stay hopeful and continue your treatment.

Dr. Yoshino, thank you so much for your wonderful insight.

Thank you.