Dr. Skip Burris from the Sarah Cannon Research Institute discusses the impact of chemotherapy on blood counts and the consequences of low blood counts.
Q: Welcome to Understanding Cancer. Today we’re visiting with Dr. Skip Burris, who is the director of drug development at the Sarah Cannon Research Institute in Nashville, Tennessee. Dr. Burris has extensive experience in new drug development as well as clinical trials in general, with a focus on oncology. Welcome.
A: Thank you.
Q: While the chemotherapy is attacking the cancer cells, does it also attack the cells, I mean, the body’s normal cells?
A: Well, and that’s the trick to managing the dose and the schedule for the chemotherapy drug. So the simplest way to think about it is chemotherapy is going to be killing cells that are dividing rapidly. So cancer cells are dividing too fast – that’s what makes them a cancer cell – so that’s part of the target for the chemotherapy.
And then you think about the side effects of chemotherapy. It tends to be those other cells that are still growing and dividing when you’re a fully grown adult. That’s why the blood counts will go up and down. Our bone marrow is our factory that’s making these red cells and white cells and platelets that keep us from bleeding, and the chemotherapy gets into the bone marrow and interferes with the production of those cells, causes those cells to die, so your blood counts will go up and down as well.
Q: What about the effect on the blood cell counts? Can that be prevented or treated?
A: That can be, and I think we need to be careful and yet aggressive about that. There’s been news out there [late] about how much we should push the drugs that will help keep our red count up. So your red blood cells carry oxygen. That’s when we commonly hear the phrase of somebody being anemic or having low blood. And really keeping up the red count, keeping up your hemoglobin hematocrit is very, very important. It helps to make the therapies work better and it’s really probably one of the primary reasons why patients feel fatigue.
I think that that’s an important part of the therapy. Doctors need to continue monitoring that. And while any therapy can be overdone, using those drugs that can support the red blood count, the erythropoietin compounds, very, very important to avoid blood transfusions where possible and to keep your energy level up where it can be appropriate.
The other factor that we have now that’s really important is the white cell stimulator. So these are drugs that in fact cause the white blood count to increase, Filgrastim and Pegfilgrastim, these drugs that will cause the white count to come back to normal more quickly, or actually, in some cases, avoiding from going too low. The white cells are your important infection fighting mechanism, and anything you can do to keep your body strong, to keep infections away from the side effects of chemotherapy really will be a better outcome for the patient.
Q: Well, also, isn’t the rate of the white blood cell recovery, after you give somebody chemotherapy, something that’s important to control in terms of the overall management of the patient?
A: It is. I think that we look at it with using white cell stimulators, using the Filgrastim and Pegfilgrastim compounds, trying to use something like that to avoid infection is one part. But you hit a key part there, too, where in terms of being able to give your therapy on time. If your counts are slow to come back and we have to delay your therapy for a week, that’s not good for treating your cancer. Part of successfully treating cancer is getting that regimen on time and getting rid of those cells as quickly as possible. So that sort of support so that your blood counts are ready for the next treatment is another key component.
Q: Are there any patient populations that are more likely to have problems with their blood counts than others?
A: So as you age, just quite naturally, your bone marrow as a factory or as a garden that’s making all these white cells and red cells, begins to age, and like any other organ in your body, so your bone marrow is not as cellular, not as active. So patients, as they get older, need to be carefully considered for use of these agents. And I certainly think patients over the age of 65, over the age of 70, are very key folks to consider for that.
I also think we need to look at patients that have co-morbid conditions, patients that have diabetes or arthritic problems or other situations where getting too weak, having your blood counts too low, getting a secondary infection, those are important places also to avoid having your counts get too low.
And then lastly, a point we often forget about, is many of our patients are able to continue working through their chemotherapy. I think continuing to work, in addition to the economic advantages, certainly is good for your state of mind. I mean, just keep on with your life, keep doing what you’re doing. So keeping your white blood count up improves the energy level, less susceptible to infection, and often makes you feel like going to work and decreases the risk of being around other people in the work place.
Q: Now, we didn’t mention platelets, which is the third blood element. I know that a low platelet count, or thrombocytopenia, isn’t a very frequent complication of chemotherapy, but it does occur. Is there anything that can be done about that?
A: So low platelets, a difficult issue. As you mentioned, it’s not as common as seeing the red count and the white blood count be lower. But in fact if the platelet count gets too low, the physician worries about bleeding, and that can be a delay in getting your next treatment. That’s something you like to avoid. And doctors don’t like to give platelet transfusions to patients if they can avoid it at all.
There are several research initiatives underway. There is an approved growth factor that will stimulate your platelets to come back. There’s been some side effects, some flu-like syndromes with that particular growth factor, so it hasn’t been as popular as we’d like, but it can be used in certain scenarios. But there’s a whole group of new drugs that are out there now for treating thrombocytopenia, low platelets, in patients that have that as a primary disorder. And we’re beginning to see research with those drugs after chemotherapy to see if we can keep the platelet counts from going down as well.
Q: These are the drugs that are currently being used to treat what we call chronic ITP?
A: Correct, ITP, idiopathic thrombocytopenia purpura, a condition in and of itself, probably due to your immune system, and your platelet counts drop very low.
Q: Well, Skip, thank you for your time today, and we really look forward to having you back.
A: Thank you.