What does low platelet counts mean in cancer patients
If you are receiving chemotherapy, at times, your chemotherapy may have been delayed because your cancer doctor told you that you have low platelets. But, what does this mean? First, what are platelets? They are like human band-aids to help with clotting blood. Whenever you cut yourself, platelets are released by the bone marrow to help with clotting blood. How does chemotherapy reduce platelet counts? When you receive chemotherapy, let’s say for colon cancer, the chemotherapy circulates throughout the body mainly to the cancer cells, but also chemotherapy attacks the bone marrow. Why is this? Chemotherapy attacks any cell in the body that is dividing. Your bone marrow contains cells that continuously make blood cell products such as white blood cells, red blood cells, and platelets. and chemotherapy will damage the bone marrow and reduce the platelet counts. Eventually, your bone marrow platelet count returns to a normal level. However, after repeated chemotherapy sessions, the bone marrow’s ability to recover its platelet count gets diminished and this results in lower platelet counts and delayed chemotherapy.
Medically speaking, platelets are called thrombocytes. Normal platelet counts are between 150,000 to 450,000 cells per microliter of blood. A microliter of blood is like a pinprick of blood. If your platelet count is below 150,000 cells per microliter of blood, then this is called thrombocytopenia. Penia means low and as mentioned before, thrombocytes are known as platelets. Hence, thrombocytopenia means low platelets. If you are receiving chemotherapy, and your platelet count is less than 150,000, this is called chemotherapy-induced thrombocytopenia. You should know that there are 4 grades of thrombocytopenia:
Grade 1: Platelet count of 75 – 149,000 cells per microliter of blood.
Grade 2: Platelet count of 50 – 75,000 cells per microliter of blood.
Grade 3: Platelet count of 25 – 50,000 cells per microliter of blood
Grade 4: Platelet count of 0 – 25,000 cells per microliter of blood.
It is expected that after you start chemotherapy, your platelet count won’t always be in the normal range. Some cancer doctors will give their patients chemotherapy as long as their platelet counts are at least greater than 100,000 cells per microliter of blood. For some other cancer patients, their ‘new’ normal platelet count might be 80,000 cells per microliter of blood and some cancer doctors will elect to have patients resume chemotherapy only if their platelet counts are greater than 80,000 cells per microliter of blood. You should ask your cancer doctor what they consider as an acceptable level of platelet counts for you to continue with chemotherapy.
Low platelet counts in hematopoietic stem cell transplant patients:
For some cancer patients who are undergoing stem cell transplant for their blood cancer, they will undergo chemotherapy prior to stem cell transplantation. This chemotherapy will cause a massive depletion of platelets which are necessary for the transplanted stem cells to repopulate the bone marrow. This massive depletion is a normal process of hematopoietic stem cell transplantation.
Besides chemotherapy and hematopoietic stem cell transplantation causing low platelets, cancer patients can have low platelets for other reasons. It may be due to the nature of cancer itself. For example, in certain blood cancers such as certain leukemias, MDS (myelodysplastic syndrome), lymphomas, and multiple myeloma, these cancers are the cause of low platelets. In the case of acute leukemias, white blood cells overcrowd the platelets. In the case of multiple myeloma, plasma cells overcrowd platelets. In the case of MDS, the bone marrow fails to produce platelets.
What is the concern about thrombocytopenia?
As mentioned earlier, platelets are human band-aids and if you have fewer of these band-aids, you may bruise and bleed easily. You have to be careful about flossing and shaving and make sure you don’t bump into things.
In the next article, I will review how to increase platelet count during chemotherapy naturally.