HARI SREENIVASAN: Some cutting-edge research is giving new hope to cancer patients.

Researchers are zeroing in on the causes of specific cancers and are finding dramatically different ways to fight the disease.

To explain the latest findings, I'm joined by Dr. David Hyman, an oncologist with Memorial Sloan Kettering Cancer Center here in New York.

So, as we talk about cancer, as we talk about hope, let's just kind of clarify, what is the current way we treat cancers, and what are some of these new studies showing?

DR. DAVID HYMAN, Memorial Sloan Kettering Cancer Center: The historic ways that we have always treated cancers is by treating them based on the organ they come from, so treating patients with breast cancer or colon cancer or lung cancer identically.

What these new types of studies are really asking is whether we can target specific mutations which are mistakes in the genes that arise in tumors and treat them the same even if they come from different organs.

So we have recognized that there are certain mutations that we find across multiple disease types.

And so one question is, can we really start to think about these diseases as diseases harboring mutation A or B, rather than lung cancers or colon cancers?

HARI SREENIVASAN: And so how effective are these drugs when they target a specific mutation, instead of a specific region of the body that the cancer is coming from?

DR. DAVID HYMAN: Well, they can be very dramatically effective in ways that are really previously unprecedented.

So, we know, for example, in lung cancers, chemotherapy has a response rate at best in the 30 percent range.

We have certain medicines now that target certain mutations in lung cancer where the majority of patients have benefit and their tumors shrink.

And so what we are trying to do is take those early successes in lung cancer, in melanoma, and now extend those to the larger variety of cancers that we see.

HARI SREENIVASAN: So how much of a sea change is this? I mean, when you think about — as we began this conversation, in my own head, I was thinking lung cancer, breast cancer, colon cancer, I mean, just like you said, right?

And now you are talking about a completely different approach to even looking at and learning these cancers and saying, here is what makes you, you.

DR. DAVID HYMAN: Yes, here is what makes this cancer tick or grow.

HARI SREENIVASAN: Right. Right

DR. DAVID HYMAN: It's — it's a really big change in the way that we think about cancer.

It really is this idea of precision medicine, you know, not treating all patients the same, but treating their individual cancers based on really detailed analysis. And I think it really represents a sea change.

Now, I don't want to give the impression that the organ in which the cancer arises has no importance.

And what we have actually seen in these studies is that certain cancer types may not respond the same.

So, a colon cancer that has a BRAF mutation may not respond as well as a melanoma with a BRAF mutation.

So I think it's going to be a combination of understanding the genetics in the cancers that we treat, and also understanding the effect of the organ where they come from.

HARI SREENIVASAN: OK.

So — and these clinical trials, are they different than the clinical trials that we are used to, where one person gets the placebo and they might or might not improve, and another person gets the real drug?

DR. DAVID HYMAN: I think they are different in a variety of ways.

Number one, most clinical trials in cancer have required specific disease types. So, everyone that goes on that trial has one type of cancer.

The clinical trials that we're doing now, these so-called basket studies, allow patients from any type of cancer to participate, as long as they have a mutation in their tumor that we think suggests they would benefit from the drug being tested.

The other point is that these trials are typically not randomized trials, meaning that everybody that participates gets the drug.

We know exactly what they're getting. And the reason for that is that the benefit that we're looking for in the form of what percentage of patients have significant shrinkage of their tumor is so high, that it's previously unprecedented for those diseases.

So, we don't really need to do randomized studies, because, if half of the patients or more are having shrinkage of their tumor, there is really no question that that treatment is better than the established care.

HARI SREENIVASAN: All right.

Dr. David Hyman, an oncologist with Memorial Sloan Kettering Cancer Center, thanks so much.

DR. DAVID HYMAN: Thank you.