Low Platelets and Treatment Update/Bloodwork Details

Blood Tests and Treatment Update #36 (TDM-1 #19) 

One of the problems with being treated for cancer over an extended period of time is the threat of injury/damage to a person’s body by the drugs given. To help lessen this, blood tests are done before each infusion to determine treatment decisions. Many times immediately after treatment, certain bodily functions decline but recover by the time the next treatment is due. For me, a CBC (Complete Blood Count) is done every time I am scheduled for another treatment. Other times a CMP (Comprehensive Metabolic Panel) is also done. See the bottom of this post for a description of these tests.

May 6th was my two year anniversary of my first treatment for stage IV breast cancer. From that day to the day of my most recent treatment, I have seen a small yet steady decline in the function of my blood cells and liver. My lab print-out always shows a number result of each test performed and then provides the standard range that the numbers should fall. Numbers too high or too low, of course, are never good. Thankfully, there is room for increases or decreases outside the normal range before the numbers are deemed dangerous.

This past Monday, I had treatment #36 (TDM-1 #19). My internet fun was interrupted by a nurse who reported a concern about one of my blood tests.  As I already stated, many of my numbers have been decreasing or increasing slightly each time I have received treatment. This time my platelet count had taken a significant drop possibly so low that treatment may have to be delayed. Dr. R had been contacted to determine if I could receive treatment.

Platelets impact the blood's ability to clot. Their counts are supposed to fall within a range of 150,000 to 450,000. My counts have been as high as 317,000 and as low 114,000 over the course of my treatment. On Monday, though, my platelet count dipped to an all-time low of 77,000.  YIKES!! I believe if the count is below 20,000, the patient may have to have a platelet infusion. I am not there yet, but still it is in the YIKES category.

In the end, my doctor decided that my current drug, TDM-1, could be reduced by 20%. That allowed me to receive treatment without putting my blood clotting ability at significant risk. At full-dose, my drug was 3.6 mg/kilogram. The reduction put my dose to be 2.88 mg/kilogram.

Scans are due the first week of June. Hopefully all will be fine, and I can continue being treated with TDM-1 (Kadcyla). No matter what happens, my blood will be tested to see if there are any changes. If my platelets have improved then my drug can be increased to full-dose again. It could also remain at its current reduced dose if my blood test numbers do not improve.

On top of being terribly tired lately, I feel like this is the downhill descent I have so vehemently feared. I hope it is not. 

Below describes the blood tests used to determine if treatments can be given.

(Some information came from Lab Test On-line )

CBC– (Complete Blood Count) and Differential (counts different types of blood cells) 
– looks at all the parts of the blood - It shows size and number of red blood cells and looks at important proteins as well as the different types of white blood cells. 

White Blood Cells- fight infections
White Blood Cell Tests – determine numbers of each
*Neutrophils Absolute                                                
*Lymphocytes Absolute                                                             
*Monocytes Absolute
*Eosinophils
*Basophils

Red Blood Cells- transport oxygen through the body
Red Blood Cell Count – number of cells in a sample of blood
*Hemoglobin – a protein in red blood cells, carries oxygen to cells
*Hematocrit – measures what percent of blood made-up of red blood cells                                                      
 
Red Blood Cells Tests 
*MCV- (mean corpuscular volume) measures average size of individual blood cells        
*MCH – (mean corpuscular hemoglobin) calculates percentage of hemoglobin inside a red blood cells, high number indicates large red blood cells, may have macrocytic anemia—not enough folic acid or B12          
*Platelet (vital to blood clotting) Counts – low number indicates lower ability of blood to clot      

Comprehensive Metabolic Panel— test are done to determine the condition of a patient’s kidneys, liver, levels of blood glucose and blood proteins along with electrolytes and acid/base balance.

Kidney Tests
*BUN (blood urea nitrogen – waste product) this product is filtered from blood through the kidneys. If not filtered efficiently, could indicate liver damage
*Creatinine – a waste product made in the muscles filtered out of blood by kidneys. If not filtered enough, kidneys may be compromised.

Blood Proteins
*Albumin – protein made in liver, carries medicine through blood
*Total Protein- measures albumin and serum blood proteins

Liver Tests
*AST – (enzyme in cells of heart and liver)-  high number means liver is being damaged,
*ALT – (enzyme in cells of liver and kidneys)- high numbers indicate liver damage
*ALP – (enzyme found in liver, bone)- high levels indicate liver problems
*Total Bilirubin (waste product) – found in bile, produced when liver breaks down old red blood cells

Electrolytes
*Potassium- needed by all cells metabolism and for muscles to function
*CO2 – needed to maintain acid/base balance in body
*Sodium- necessary for normal bodily functions such as nerve and muscle
*Calcium- needed for muscle, nerve, heart function, required in blood clotting and development of bones
*Chloride- necessary to maintain fluid balance in body and acid/base balance
*Glucose- body needs this for energy

** Remember I am a patient and not a doctor. If you see anything wrong with my descriptions, please let me know.