Welcome to one of the most controversial issues in oncology!
Patients with cancer are often anemic. This anemia can be from an inflammatory state from the cancer and/or from chemotherapy. Anemia can produce symptoms of fatigue, shortness of breath (at rest or exertion), impaired concentration, depression. These can also be symptoms of cancer or of chemotherapy side effects as well. You can imagine that the picture gets cloudy when it comes to thinking about what is the cause of your fatigue if you are a cancer patient on chemotherapy with anemia-cancer, chemotherapy, and anemia may all be playing a role.
If you have significant anemia with symptoms, and would consider treatment of this anemia to maybe make you feel better, you have two options: a blood transfusion or erythropoesis stimulating agents (ESAs, also known as Procrit, Aranesp). Both options have benefits and risks.
If your hemoglobin approaches 8 regardless of your symptoms, we will consider a blood transfusion. The cutoff is a little lower for younger patients (i.e. about 7) and a little higher for older patients (i.e. about 9).
Benefits of Blood Transfusions:
- Immediate relief of anemia
Downsides of Blood Transfusions:
- Allergic reactions to someone else’s blood (note you can still react to a family member’s blood!)
- Setting up and getting a transfusion takes time (6-12 hours for the whole process, or sometimes an inpatient admission)
- Transfused blood lasts a few days to few weeks in your body
- Infections (note that the risk of Hepatitis or HIV is in the order of 1 in a million)
ESAs (Procrit, Aranesp)
A hormone called erythropoietin is produced by the kidneys that stimulates your bone marrow to make red blood cells. This hormone was synthesized in the 1980’s and in 1993, Procrit started being used for chemotherapy related anemia. Aranesp was approved in the early 2000’s and is a long acting form of Procrit. Procrit is usually given weekly (or less often) and Aranesp is usually given every 3 weeks (or less often). Both medications and the medicine Epogen (the same thing as Procrit) are used also in patients with anemia related to kidney failure.
Back in 2006, several studies were released in patients with a variety of types of cancers that showed that patients receiving ESAs died sooner than patients not receiving ESAs. The major concern with these kind of studies is whether ESAs stimulated tumor growth, and is that why patients were dying sooner? Or was there some other mechanism, such as increased blood clots, that was causing patients to die sooner? Note that many studies also showed no harm from ESA use, so there is controversy as to whether they are dangerous or not. While the studies showing harm were not perfect (for example, patients were boosted to normal levels of hemoglobin with ESAs which is not done in practice), there was sufficient concern by the FDA to lead to 2 national meetings, new warning labels on ESAs, and the mandate for informed consent for a patient who agrees to use ESAs. Additionally, while the hemoglobin prior to 2007 was allowed to be boosted to as high as 12, this ceiling was lowered to 10 (an arbitrary value without clear evidence based on studies) in 2007.
As you can imagine, some patients were put off by the question of whether ESAs stimulate cancer cells, and the use of ESAs fell significantly since 2007. Nevertheless, some patients still are OK with using them. Note that there was controversy once upon a time whether blood transfusions stimulated cancer cells through immune cells contained in transfusions!
ESAs in cancer patients are currently used in the minimum dose needed to avoid transfusions and are not to be used to boost the hemoglobin over 10. They are not to be used when you are not on chemotherapy (though they can be used after chemotherapy is finished to speed up your recovery from anemia).
Benefits of ESAs:
- Quick injection
- Few side effects (other than what I have said above)
Downsides of ESAs:
- Take 4-6 weeks to work
- Two major controversies:
- Do they stimulate cancer cells?
- Do they increase blood clot risk at current dosing regimens?
- In my opinion it will be very hard to answer these questions due to the size of the studies required and patient reluctance to participate in these studies.
*I know too much about the ESA topic because this was my pet project at the FDA from 2006-2008! Google my name and Procrit/Aranesp if you are interested in finding out more.