JOHN YANG: Bowel cancer or cancer in the colon or rectum is the second leading cause of cancer deaths worldwide killing nearly 1 million people a year and cases of colorectal cancer have been on the rise, especially among those younger than 50.

But there are glimmers of hope for patients with a certain type of bowel cancer in two separate studies, one in the United States and a more recent one in Britain.

Each found that using immunotherapy drugs before surgery dramatically increased the chance of curing bowel cancer in patients with a certain genetic profile.

Dr. Vikram Reddy is chief of Colon and Rectal Surgery at the Yale School of Medicine.

He's not affiliated or connected with either of these studies.

Dr. Reddy, how potentially how big a deal is this?

DR. VIKRAM REDDY, Yale School of Medicine: So this is a huge deal for us because it's a new category of medications that we can use to treat patients with bowel cancers.

JOHN YANG: And immunotherapy drugs tell us what is immunotherapy and how does it work?

VIKRAM REDDY: So immunotherapy is different from conventional chemotherapy.

So immunotherapy actually augments and uses your own immune system to fight the cancers.

Whereas the old conventional chemotherapy, we were targeting the cancer cells and killing them with drugs.

JOHN YANG: And or immunotherapy drugs used in other types of cancer?

VIKRAM REDDY: Oh, yeah, immunotherapy drugs have been used and other kinds of cancers for a while.

But recently, we've been using them for colorectal cancers.

JOHN YANG: What more do you want to know about these drugs?

They're going to continue to try clinical trials, sort of looking at long term results, and relapses, what else do you want to know?

What should the researchers be looking at?

VIKRAM REDDY: I think what the immunotherapy trials, we're seeing a lot of promise in them creating colorectal cancers, we want to see if they can maintain those over a longer period of time.

So whenever we have a patient with cancer, we follow them for five years or even more to make sure the cancer doesn't come back.

Now, most of these trials have been going on for about a year to two years.

So we have short term data, they're very promising.

We just want to make sure there's a sustained response even five years.

JOHN YANG: And as I understand it, there's only - - they've only been testing or there's only been effective found to be effective among patients with a certain genetic pattern.

How widespread is that?

How many colorectal cancer patients have that genetic pattern?

VIKRAM REDDY: So about 15 percent of the patients have these types of cancers called mismatch repair deficient type of colon cancers.

So in those patients, these immunotherapy drugs can work beautifully.

In the past conventional chemotherapy did not -- was not effective against these patients.

But now with immunotherapy, we can actually make a difference for these patients.

JOHN YANG: Why are cases of colorectal cancer on the rise, especially among young people?

VIKRAM REDDY: So it's a multitude of factors, you know, one, you know, our diets have changed.

So diets high in red meat, processed meat, sugars, sedentary lifestyle, these are all associated with an increase in colorectal cancers.

And unfortunately, all of these are going up over the past two decades, and that's why we're seeing an increase in colorectal cancers.

JOHN YANG: Does it suggest that there should be screening earlier are screening in particular cases earlier?

VIKRAM REDDY: So in in the older days, I mean, before 2021, you know, we used to actually start screening people starting at the age of 50.

And in blacks, we used to do it at 45.

But in 2021, we actually changed the guidelines to start screening at 45.

But unfortunately, we even see patients as young as 2018, who are getting colorectal cancers.

So even though what I tell everyone is that if they have any bleeding, like rectal bleeding, if they have abdominal pain, if they have change in their bowel habits, like you know, if you're usually having one problem today, and now you're constipated, or you're having diarrhea, which persists, I say get a colonoscopy, because it can diagnose you, it can even create an early polyp, it can even get rid of the cancer, if it's early stage.

So a colonoscopy is important, but unfortunately, screening by itself only starts at 45.

JOHN YANG: And we've said in the introduction about how prevalent deaths from colon cancer are in terms of cancer deaths, but if it's caught earlier, does that change that that sort of prognosis?

VIKRAM REDDY: Oh, yeah, early stage cancers, the survival is so much better than advanced or metastatic cancers, once it metastasizes.

I mean, our survival is still pretty good.

But you know, you're talking about maybe 50 percent survival, if you resect all metastatic disease.

If you can resect metastatic disease, you know, the survival is much lower.

So if you catch them early, you're looking at almost close to 100 percent.

And especially if you have this MMR deficient, which is the mismatch repair deficient kinds of cancers, with these new category of drugs, I mean, you're, you're talking about a cure.

JOHN YANG: Earlier, we talked about the things that seem to be contributing to the increased number of colorectal cases.

What can people do?

Are there things people can do in terms of diet and terms of lifestyle to reduce the chances of developing colorectal cancer?

VIKRAM REDDY: Absolutely, you know, what I tell patients are, you know, trying to minimize how much red meat really and pork counts as a red meat.

The second thing is try not to eat any processed meat.

Third thing you know, try to increase your fiber intake.

Fiber intake usually comes from fruits and vegetables, so increase your fiber intake to back 25 to 30 grams of fiber a day.

Fourth thing there's some data to show that to tablespoon full of tree nuts like walnuts, almonds or pecans can actually decrease the incidence of colorectal polyps and colorectal cancers.

So I tell them to do those.

The last thing is 30 minutes of exercise five days a week can actually, you know, mitigate the incidence of colorectal cancer.

JOHN YANG: Dr. Vikram Reddy of the Yale School of Medicine.

Thank you very much.

VIKRAM REDDY: Oh, you're welcome.