Chemotherapy: metronomic

Metronomic chemotherapy involves giving small regular doses of chemotherapy. This can be administered at home.

 

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Traditional chemotherapy involves giving a large dose of the chemotherapy drug and then giving the body time to recover. Metronomic chemotherapy is different as it is given at a low dose at regular intervals, usually daily or every second day. The chemotherapy drugs are given orally at home. This treatment suppresses blood vessel growth (angiogenesis) and stimulates the immune response against cancer rather than directly killing the cancer cells. If cancer cells lose their blood vessel supply, they are starved of oxygen and nutrients, and will die.

Metronomic chemotherapy can be used to treat a range of tumors and may be used after traditional chemotherapy or on its own. It may be used to slow tumor growth or to try and prevent recurrence.

Metronomic therapy typically consists of a combination of two drugs: cyclophosphamide and a non-steroidal anti-inflammatory drug such as meloxicam.

Other chemotherapy drugs may be given in metronomic protocols.

The low dose of drug used in metronomic chemotherapy means that the risk of side-effects are much lower. The dose used is usually less than 1/10th of that used in traditional chemotherapy protocols. However, it can take a longer time for the drugs to be effective and so this may not be the best treatment in patients with fast growing tumors.

• Always follow the instructions provided by your veterinarian and make sure that the drugs are stored correctly and securely.
• Always wear disposable gloves when handling the drug, and wash your hands immediately afterwards.
• Pregnant women or young children must not handle cytotoxic drugs such as cyclophosphamide (and the drug must not be given to another person or another pet).
• Contact your veterinarian immediately if you have given more than the recommended dose.

Your cat will excrete products from the chemotherapy drug for a number of days after administration and this period is referred to as a the “chemo barrier” period. If your cat is on regular chemotherapy tablets then this period is in place throughout treatment and for 7 days after the final treatment is administered.

The risk of you absorbing any of the toxic products from your cat is small. However, as the risk cannot be quantified, there are some sensible precautions you should take to reduce your exposure during this time.

• Wear gloves when  handling any urine, feces, vomit or saliva from your cat. 
• Always wash your hands after handling your cat and before eating or drinking.
• The following people should minimize direct contact with your cat:
  • Pregnant or breastfeeding women
  • Young children who do not understand the need for hand washing after contact
  • Immunosuppressed or receiving chemotherapy or immunosuppressive drugs
• Outdoor cats should be kept indoors for 72 hours after treatment, particularly if they have access into parks or areas where children play.
• Cat litter trays should be lined with plastic litter tray liners and filled with clumping cat litter. This is to prevent contaminated dust.
• Wear gloves when handling the litter tray contents.
• Empty the tray by lifting all the litter out with the liner as soon as possible after soiling to prevent your cat from scratching around in their dirty tray. It may be sensible to use a smaller amount of litter when you refill it during this time. Covered litter trays will restrict the amount of dust that can be spread into the air.
• If your cat has an accident in the house or has soiled itself, you should wear gloves to clean the area as quickly as possible using copious amounts of soapy water. Use disposable paper towels to dry the area and dispose of these in a plastic bag in an outside bin.
• Your cat’s bedding should be washed regularly as some toxic products may end up on your cat’s coat when they lick themselves.
• There is no risk to other pets in the home from sharing water bowls or toileting in the same litter tray.