My pet has cancer…are they in pain?

As an oncologist who sees many pets with cancer this is one of the questions that I sometimes find the hardest to answer.  A few years ago I found a very small swelling under my armpit that hurt when I touched it.  My doctor told me “not to worry…if it hurts it probably isn’t cancer.”  Fortunately for me he was right, but for a lot of our pets with cancer their tumors are more advanced when we find them, so they often are painful at that point. 

How can you tell if your pet is in pain?  There are some signs you can look for.  If your pet is limping it almost always is from pain.  If your pet has a tumor that is damaging bone anywhere in the body this is painful.  If your pet is acting abnormally in any way they may have pain.  For example, if they have an oral tumor and they won’t eat this is likely due to pain.  If your pet’s tumor is red or swollen or they are licking, scratching or biting at the tumor it probably hurts.

However, it is important to remember that some pets will never show these signs, even with a painful tumor.  Not that long ago dogs and cats were wild animals and their natural instinct is to hide pain… or be eaten!   Cats may hide more or have a decreased appetite when they are in pain but most cats show no signs of pain.  Many large breed dogs such as retrievers will wag their tail and beg for food, even with a tumor that we know would be horribly painful in a person.

It is very important to try to identify whether your pet is in pain because controlling that pain will improve their quality of life and in some cases can improve their response to treatment.  The best way to get rid of pain from a tumor is to get rid of the tumor.  Surgery, radiation or chemotherapy may help achieve this, but in cases where the tumor cannot be removed or controlled, pain management is important and veterinarians are getting much better at it.  Currently there are many more choices for pain control in pets than there were in the past.  Non-steroidal anti-inflammatory drugs, pain killers like buprenorphine and gabapentin help keep animals comfortable.  Also radiation can be very effective in controlling pain for certain tumors.  In some cases acupuncture may be used.

So if your pet has cancer of any type, whether you are going through treatment or you just want to keep them comfortable, ask your veterinarian to help you determine if your pet is in pain, and discuss what you can do to make them comfortable.

John Farrelly, DVM, MS, ACVIM (Oncology), ACVR (Radiation Oncology)
The Veterinary Cancer Center