Chemotherapy in Cats

Chemotherapy is the term used for a group of drugs designed to kill cancerous cells in the feline body. Chemotherapy can be administered in one of five ways; intramuscular (in the muscle), intralesional (injected directly into the tumor), subcutaneous (under the skin), intravenous (in the vein), or oral (by mouth).  Chemotherapy is administered by a veterinary oncologist only. The veterinary oncologist has a variety of chemotherapy drugs available to them to treat cancer and will use these drugs in combination to treat a feline’s cancer type. Common drugs used in chemotherapy include; L-asparaginase, Vincristine, Cyclophosphamide, Doxorubicin, Prednisone, Asparaginase, Cytoxan, Chlorambucil and Methotrexate. The duration a treatment lasts depends on the type of cancer the feline is diagnosed with. Chemotherapy can be given every week, but the oncologist may only require treatment every three to four weeks.

Chemotherapy is administered in a number of ways. Intravenous chemotherapy administration will be discussed here. Prior to the date of chemotherapy infusion, the oncologist will have already discussed the drug combination he or she plans on administering to the cat. On the day of chemotherapy administration, the veterinarian oncology staff will check your feline in and take vital signs. The feline’s weight, respiratory rate, temperature, pulse and blood pressure will all be taken prior to chemotherapy infusion. The feline will then be taken into the preparation area where she will be readied for therapy. 

1. An IV (intravenous) catheter will be placed. The placement of this catheter depends on the veterinarian’s personal judgment and the health of the feline.
2. To place a catheter, the feline’s hair may be shaved to view the vein. The area will be cleansed with alcohol prior to catheter insertion. 
3. The catheter has a needle inside the catheter casing and once the correct placement is made, the needle will be removed, leaving the catheter in place. 
4. The catheter will be capped off to prevent blood from leaving the vein. The technician will tape the catheter in place to ensure it will not move out of the vein during feline transport. 
5. The technician will take a sample of the cat’s blood during the IV placement to perform a complete blood cell count. A CBC simply evaluates the number of white and red blood cells the feline has at the current time. The results will be evaluated before chemotherapy drug values will be calculated. 
6. A pre-chemotherapy medication will likely be administered to the feline at to prevent nausea and a possible allergic reaction. Nausea and an allergic response are common responses to chemotherapy. 
7. The veterinarian technician may begin administering fluids through the IV catheter before infusing the drugs, as fluids help the drugs work more efficiently. 
8. The feline’s vital signs will be taken again. 
9. The infusion process will begin. Chemotherapy infusion can take several hours to complete. 
10. After the infusion process is complete, the technician will remove the IV and ensure the feline is stable by once again recording her vital signs. 
11. Before being released, the veterinary oncologist will review possible side effects (nausea, tiredness, etc.) and a schedule for the next chemotherapy session. 

The efficacy of chemotherapy in cats depends on the type of cancer, the stage of cancer, and how the feline’s body reacts to the cancer drugs. Felines that have stage 1 or stage 2 cancer types have a positive prognosis for a full recovery, whereas stage 3 or 4 type cancers have a poor prognosis. 

Immediately following chemotherapy infusion, your cat will need to drink plenty of fluids and follow prescribed tablet drugs as directed by the veterinary oncologist. Nausea drugs and prednisone are common take-home drugs given to almost all chemotherapy patients. Make sure to follow the administration schedule exactly as directed by the veterinarian for the best possible outcome. Cat owners should expect side effects of nausea, vomiting, tiredness, constipation, and abnormally dark urine coloration. 

The cost of chemotherapy treatments for cats can cost pet owners from $200 to $2,000, depending on the length of treatment. Pain and nausea medications can add another $25 to $50 in oral drug therapy costs. 

Many cat owners are concerned about putting their feline through chemotherapy, due to the duration and effects of the drugs. However, chemotherapy for felines is much milder than in human medicine and the side effects are not as severe. 

As scientists still do not know the exact cause of cancer, preventing this disease is difficult. Diet, medications, life style and use of chemical products are believed to be possible causes of cancer, but not enough evidence has been found to support these theories. Chemotherapy does not provide a permanent resolution of cancer in cats.