Anemia is defined as too few red blood cells or red blood
cells that don't work as well as they should.
Red blood cells contain hemoglobin which use iron to help
transport oxygen throughout the body. Red blood cells pick up
oxygen in the lungs, and carry it to the body's tissues. The red
blood cells deliver the oxygen to the tissues and pick up carbon
dioxide, a waste product. The red blood cells then bring the
carbon dioxide back to the lungs where it is exhaled and
released from the body.
If the number of red blood cells decreases quickly then the
person with anemia can feel sick right away. If the red blood
cell count falls slowly over a longer period of time, the body
adjusts. In this case, the person may not feel sick - just tired
If there are not enough red blood cells, the tissues don't
get enough oxygen. When the body's tissues don't get enough
oxygen, then they aren't able to do their normal jobs. For
- The body tells the heart to pump faster to get more oxygen
to the tissues. As the anemia gets worse, the heart beats
faster, called tachycardia. At first, it happens only with
activity, but later the heart beats fast at rest. Sometimes,
the heart can skip a beat or two. The irregular beat is
called an arrhythmia.
- If the person has heart disease, then the person may get
chest pain if the heart muscle isn't getting enough oxygen.
- The person may feel dizzy, or feel faint when moving from
lying to standing positions. The person often feels tired,
since oxygen is like energy. The muscles in the body need
oxygen to walk, talk, and do any exercise. When anemia is
slight, the person may just be a little more tired than
usual after doing an activity. When the anemia is severe, it
can make the person exhausted, or may prevent the person
from doing anything at all.
The body also tells the lungs to breathe faster to bring in
more oxygen, so if the anemia is severe, the person may have
fast breathing, called tachypnea.
The brain also needs oxygen. If the anemia is severe, then
the person may be indifferent or have trouble making decisions
With severe anemia, the person will be very sensitive to cold
temperatures, and have difficulty sleeping (insomnia). A blood
test, called a complete blood count, can tell how many red blood
cells and how much hemoglobin are in the blood. These laboratory
values are shown below in Table 1.
Normally, the body makes enough red blood cells with
hemoglobin to replace the ones that the body has used up. A
hormone called erythropoietin, which is made in the kidneys,
tells the body when more red blood cells are needed. Red blood
cells are produced in the bone marrow (inside the bones). Normal
red blood cells live about 120 days, or 3 months.
Anemia can happen when the:
- body can't make enough red blood cells (such as with
- body loses too many red blood cells (such as with
- red blood cells in the body are destroyed (such as with
- red blood cells don't work right (such as with sickle cell
The most common cause of cancer-related anemia is body's
inability to make enough red blood cells (Arnold et al, 2001).
This can happen because of the cancer itself (called anemia of
chronic disease), treatment , or because cancer cells are in the
bone marrow and, are crowding out the normal red blood cells.
Doctors and scientists are not sure what causes anemia of
chronic disease. It seems like the body tries to fight the
cancer by forming an army of immune cells. This causes an
inflammatory reaction, like with an infection. The immune cells
make chemical messengers called cytokines. Scientists know of
two cytokines -- interleukin 1 (IL-1) and tumor necrosis factor
(TNF). Cytokines may stop the iron from getting into the red
blood cells, which prevents red blood cells from being made.
Cytokines may also lower the level of the hormone erythropoietin,
so that bone marrow is not told to make more red blood cells. If
the red blood cells are made in a person with anemia of chronic
disease, they don't seem to live as long as normal red blood
Sometimes, cancer treatments such as chemotherapy or
radiation can cause anemia by damaging healthy cells and organs.
Radiation treatment to areas like the pelvis, which includes
bones with bone marrow, can cause anemia. People who receive a
combination of chemotherapy and radiation therapy usually
develop anemia. Cisplatin, a chemotherapy drug, can injure the
kidney, so it lowers the production of erythropoietin and red
blood cells. Without erythropoietin, the bone marrow is never
told to make more red blood cells. When the healthy red blood
cells die after about 3 months, there are no new red blood cells
to replace them and the person gets anemia. This is why some
people get anemia months after treatment ends.
Another cause of anemia is f the body doesn't have the
building blocks it needs to make red blood cells. One important
building block is iron. Normally, the body gets enough iron from
food, but iron can be lost if the person has bleeding from the
stomach or intestines. If the body loses more iron than it takes
in, it causes iron deficiency anemia. A lack of folic acid (folate)
can also cause anemia.
The treatment of anemia depends upon the cause. If the anemia
is due to a lack of red blood cells, then red blood cells can be
given through transfusions or treatment.
Red blood cell transfusions are used a lot of the time to
treat anemia caused by cancer or its treatment when the
hemoglobin is less than 8g/dL, the hematocrit less than 25%, or
the person has symptoms. Red blood cells are looked at closely
before they are given to someone to make sure that they match
the person getting them. However, people can still have
reactions to the red blood cell transfusion. To lower the chance
that this happens, a special blood filters is usually used to
administer the blood transfusion, or the red blood cells are
irradiated. Some people donít want red blood cell transfusions
for cultural reasons, such as people of the Jehovahís Witness
PROCRIT can sometimes help these people become less anemic
without red blood cell transfusions. This is made in the
laboratory using special (recombinant DNA) methods so that it is
identical to the bodyís erythropoietin. When epoetin alfa is
given, it can take approximately four weeks to raise the
hemoglobin and hematocrit.
For most people receiving chemotherapy that have been
diagnosed with anemia, PROCRIT can be given to improve
hemoglobin and reduce red blood cell transfusions (Cascinu et
Keeping a personís hemoglobin above 12 g/dL has other
benefits as well. Cella (1998) studied patients with anemia at
Rush-Presbyterian-St. Luke's Medical Center in Chicago and found
that people with hemoglobin levels higher than 12 g/dL had fewer
symptoms of anemia such as fatigue, shortness of breath, and
fast heartbeat. Demetri from the Dana Farber Cancer Center and
colleagues (1998) studied over 2200 people receiving
chemotherapy, and found that PROCRIT improved hemoglobin values.
If a person has anemia due to iron or folate deficiency, then
the person will need to take supplements and change their diet
to eat more foods high in iron or folate. Foods high in iron are
green leafy vegetables, organ meats including liver, nuts, egg
yolks, molasses, whole grain cereals, shellfish, apricots,
peaches, potatoes, prunes, and grapes. Foods high in folate are
green leafy vegetables, asparagus, bananas, fish, oatmeal, beef
liver, wheat bran, and peanut butter (Lynch, 2001).
Iron supplements and erythropoietin are being studied in
people receiving radiation and chemotherapy to prevent anemia
and improve response. People at risk for nutritional problems
can decrease the risk of anemia by eating foods high in iron,