What exactly is chronic lymphocytic leukemia (CLL), and what factors help determine a diagnosis? Dr. Jennifer Woyach explains how CLL originates and transforms, the tests involved in diagnosis, and shares a common misconception about CLL.
Dr. Jennifer Woyach is a hematologist-oncologist specializing in chronic lymphocytic leukemia (CLL) at Ohio State’s Comprehensive Cancer Center – James Cancer Hospital & Solove Research Institute. Find out more about this expert here.
Well, Dr. Woyach, let’s start by understanding CLL. Would you briefly walk us through what CLL actually is?
Sure. CLL is a cancer of the blood, the lymph nodes, and the bone marrow.
And it happens when a particular type of white blood cell called a B lymphocyte acquires genetic mutations and transforms into a cancer cell. And then, over time, those cancer cells continue to grow and divide. And they can cause symptoms such as enlarged lymph nodes if the cells get stuck in the lymph nodes and continue to grow there. It can cause a high white blood cell count, which usually doesn’t cause any symptoms but is one of the things that we see often in CLL. And then, it can also cause the bone marrow to not be able to produce normal cells because it can get so infiltrated or so full of CLL cells.
And this can cause things like anemia, which is lowering of the red blood cell count and thrombocytopenia, which is lowering of your platelet count.
What are the steps involved in reaching a diagnosis?
CLL is an interesting disease because it’s one of the only cancers that does not require a biopsy of something for a diagnosis.
So, we can, actually, make the diagnosis of CLL based on the peripheral blood. So, just a blood draw in somebody’s doctor’s office. Usually, CLL is diagnosed in the asymptomatic stage. So, somebody goes to their primary care doctor, has blood drawn usually for another reason, and is found to have a high white blood cell count or sometimes even a fairly normal white blood cell count but a high percentage of lymphocytes. That certain type of cancerous white blood cell. So, the next step in the diagnosis then is something called peripheral blood flow cytometry, which is a specialized test where we look at the markers or antigens on the surface of white blood cells.
So, there is kind of a code of these markers on the surface of all of your blood cells that can tell what type of cells they are. So, for CLL in particular, we’ll see that the cells express some of the normal markers we would see on a normal B lymphocyte.
Things like CD19, CD20, CD23. But they also express a marker called CD5, which is found on normal T lymphocytes but shouldn’t be found on B lymphocytes.
And so, this collection of surface markers can make the diagnosis of CLL. Sometimes, we do need to do extra studies like a bone marrow biopsy or a lymph node biopsy. But often times, those are not necessary at the time of diagnosis.
When you meet with patients, Dr. Woyach, what are some common misconceptions that you hear about?
I think the biggest thing that I hear, and granted I see a lot of patients after they’ve been diagnosed by someone, gone to see an oncologist and then, come to me after, but one of the common things that I hear is that somebody has told them along the way that they have the good type of cancer, which I think is not a very helpful thing to hear as a patient because, of course, no cancer is a good type of cancer.
I think it’s important to note that CLL is one that has a lot of treatment options and usually extended survival. But I think that’s one of the most common misconceptions that I hear.