Cancer Mythbusters: Leukemia Myths

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MEGAN: Hi. I'm Megan Riesz, and this is Cancer Mythbusters, a podcast from Dana-Farber Cancer Institute about the many myths and misconceptions in the world of cancer. Every episode, we'll take a look at a myth and debunk it with the help of our world-leading clinicians and researchers.

Leukemia, a type of blood cancer that affects the blood and bone marrow, is one of the most well-known types of cancer. In the case of leukemia, the bone marrow produces abnormal blood cells, suppressing the production of normal blood cells that help the body fight off infections. There are many different myths and misconceptions floating around about this cancer, which we'll address with the help of Dr. Daniel DeAngelo, Director of Clinical and Translational Research for the Adult Leukemia Program at Dana-Farber Cancer Institute.

Thanks for joining us, Dr. DeAngelo.

DR. DEANGELO: Thanks for having me.

MEGAN: So, to start off, one common myth is that leukemia only affects children. Can you talk about this and explain how leukemia can be similar or different in people of different ages?

DR. DEANGELO: That's a great question and a fact that even as a medical student I thought predominantly that children were the ones afflicted with leukemia, because that's what you see on TV, but it may surprise the audience that patients of all age groups get leukemia and there's different subtypes of leukemia.

So, there are pediatric leukemias, something called acute lymphoblastic leukemia, which is more common in children but can happen in adults. In fact, 15 percent of adults can have acute lymphoblastic leukemia.

In terms of acute myeloid leukemia, another type of leukemia, it's actually a disease of the elderly, patients' average age around 65, although, again, all age groups can get those leukemias from infants to older adults, so it doesn't discriminate by age.

MEGAN: Great. Thanks. So, some people also think that leukemia manifests itself through very obvious symptoms, so the idea there is that you can definitely tell if someone has leukemia because they look sick or ill. So, can you talk about this and go over some common symptoms of leukemia?

DR. DEANGELO: Yes. So, another very important fact and one that I try to spend a lot of time when I'm teaching the medical students, because the presentation of patients specifically with acute leukemia is very nondescript and very general, and if you think about it for a second, leukemia affects the bone marrow and the bone marrow is inside all of our bones and it's responsible for making the white cells, the red cells and the platelet cells, which help clot the blood.

So, when you have too many cancer cells, specifically leukemia cells in the bone marrow, what happens is that the normal bone marrow function doesn't work, so patients don't usually present with symptoms of the cancer. They present with symptoms of not having a normal bone marrow. So, what is that?

• So, a lower number of normal infection-fighting cells, so more infections, and we all get sick, but an infection that doesn't get better or it comes back again and again.
• Fatigue. Low red blood cell count causes anemia, so patients present with fatigue. “I used to play a couple of sets of tennis,” and now the patient says, “After one set of tennis or even a couple of games, I'm just winded.” Again, it could be anything, but anemia, profound anemia is often a common manifestation.
• And bruising or bleeding. It could be as simple as a patient cutting him or herself when shaving or noticing some odd bruises, but didn't really have any trauma.

So, again, very nondescript symptoms, representation of bone marrow failure, not necessarily the leukemia itself.

MEGAN: Great. Thanks. And I think a lot of people are surprised to learn there are many different types of leukemia. So, can you explain kind of the most common different types and very generally how they're different?

DR. DEANGELO: Sure. Yes, so, I like to balkanize the world into little groups. So, there are acute leukemias and chronic leukemias.

Acute leukemias are defined as diseases that occur over weeks or months, so they present themselves very rapidly, acute onset. Patients can get very sick very quickly presenting with symptoms, like I said, of bone marrow failure often.

Then there are the chronic leukemias that occur over months to many, many years before patients present with symptoms.

The acute leukemias usually present on looking at the blood smear or the bone marrow with baby white cells or immature white cells versus the chronic leukemias have more mature cells.

And then, both acute and chronic can be further divided into either lymphoid or myeloid. So, for example, acute lymphoblastic leukemia is, as I mentioned earlier, a disease that's more common in children, but still about 10-15 percent of adults can get that. Acute myeloid more common in adults, the kids can get that in about 5-10 percent, and the same thing with chronic leukemia. We have chronic myeloid leukemias and chronic lymphoid leukemias.

And then, just to complicate the world of acute leukemias, each subtype, acute lymphoid and acute myeloid, can be divided into different subgroups. For example, acute lymphoid whether it's a B-cell or a T-cell — these are two different types of lymphoid cells that we have — and then it's further divided into different cytogenetic or molecular subgroups.

So, it becomes very complicated very quickly, but the point is that not everybody's leukemia is the same and, therefore, not everybody's leukemia should be treated the same.

MEGAN: Makes sense to me. So, some people also think kind of along those lines that leukemia is incurable. So, can you kind of talk about that and talk about some recent treatment advancements in the area?

DR. DEANGELO: So, leukemia historically back in the 1940s and '50s was an incurable disease.

Our pediatricians have really changed the viewpoint of how this disease can be treated and that has extended into the adults as well. So, nowadays, pediatric leukemias, specifically acute lymphoid leukemias, about 85-90 percent or 90 percent probably are cured of that disease.

In adults, the results are not quite as good, but we do see incremental improvements. So, for example, in what we call the young adults, AYA population, which is usually 40 and under, we're curing now almost 70 percent of our patients. For adult patients, 60 and under, we're curing about 50-65 percent of our patients. Where we're struggling a little bit is in our older adult patients over 60, but, again, some of those patients are being cured.

Why the big improvement over the last decade or two? Better chemotherapy regimens, better supportive care regimens, knowing what subtypes of leukemia and how to direct that therapy, improvements in transplant for those patients who need to be transplanted.

With respect to the other acute leukemia, acute myeloid leukemia, overall from 18-80, about half of those patients can be cured. Again, it's dependent upon the patient's age, how well the patient is; all those different genetic subgroups all have different influences on prognosis.

So, it's not what it was in the old days, so at least half the patients over all can be cured and there's different groups of patients have different prognoses, of course.

MEGAN: Great. So, kind of generally, what other misconceptions about leukemia would you think about that you might want to squash for our listeners? And there might be patients who have been diagnosed or families or friends.

DR. DEANGELO: Yes. So, first of all, it's the one that we just discussed where it's a terminal disease and that's clearly not the case, and I always tell my patients, not every patient, of course — you have to be very honest — but I tell the majority of my patients the focus of our treatment is cure and that we're going to try and get the disease into remission, and once we get a disease into remission we're going to focus on how best to cure. Sometimes that's with chemotherapy. Sometimes that's with bone marrow or stem cell transplant. And I think that our patients need to know that this is a treatable disease and I think that's often a misconception.

The other thing that's a misconception is that everybody needs a stem cell transplant. That's not the case. There are clearly those patients whose disease is best befitted by transplant, but a lot of types of leukemia now can be treated with chemotherapy, traditional chemotherapy, as long as you understand the setting for which that choice is the best.

MEGAN: Makes sense. Thanks for clearing all this up and thanks for joining us, Dr. DeAngelo.

DR. DEANGELO: My pleasure.

MEGAN: So, to sum it up, patients of all ages can get leukemia from infants to older adults. Symptoms of leukemia can be very general and nondescript, such as fatigue and bruising. There are different types of leukemia which can be grouped into acute leukemias and chronic leukemias, and it's a complete myth that leukemia is incurable. Thanks to advancements in treatment such as better chemotherapy and transplant regimens, many patients can be cured of their disease.

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