Chemotherapy (i.e., the use of chemo drugs) can be a very effective part of the treatment of breast cancer. Chemotherapy drugs work by targeting cells that divide rapidly. However, cancer cells are not the only cells that divide rapidly. Normal cells in the bone marrow also divide rapidly. Unfortunately, the production of healthy cells in the bone marrow also may be affected by certain types of chemotherapy drugs.
When certain chemotherapy drugs produce the side effect of lowering the level of cells in the bone marrow, resulting in abnormally low number (i.e., counts) of cells in the blood, the condition is called myelosuppression (and the side effect is called a myelosuppressive effect). Depending on the kinds and doses of the chemotherapy drugs used, cancer patients may experience one or more of the following signs of myelosuppression, which can be detected by a laboratory test called a complete blood count (CBC):
• Anemia (a low level of red blood cells)
• Neutropenia (a low level of neutrophils, a certain type of white blood cell)
• Thrombocytopenia (low level of platelets, cells that are involved in the clotting of blood)
When the amount of a specific type of blood cell decreases to the lowest level during chemotherapy, the lowest level of that type of blood cells is called the nadir.
Some cancer patients may experience one or more of the following types of symptoms of the myelosuppressive side effects during the treatment:
• Fatigue due to anemia
• Infections due to neutropenia
• Bruising and bleeding due to thrombocytopenia
Be sure to tell your oncologist if you are experiencing any of these myelosuppressive side effects during chemotherapy. Various medicines and other therapies are available to minimize and manage many of these myelosuppressive side effects of chemotherapy. See our Q&As on the specific side effect and its management and treatment.
Most of the myelosuppressive side effects of chemotherapy usually go away during the recovery period portion of the chemotherapy cycle or after all of the chemotherapy treatment has been completed. Consult your oncologist if you are experiencing any of these myelosuppressive side effects during the recovery period part of the chemotherapy cycle or after all of the chemotherapy treatment has been completed. Various types of medications and other forms of therapy are available for management of myelosuppressive side effects that persist past the completion of chemotherapy.