Tumor 1

Norah has what is likely a mammary tumor behind her right armpit

Most often, it’s quite easy to catch tumors when they’re small. If you handle your rat every day, you’ll be able to feel when a small mass first appears. Another way to find growths on your rat is to simply observe him or her closely. As long as you’re handling and interacting with your rats on a daily basis, you’ll become aware when a tumor develops.

Male and female rats can both get tumors. It’s more common for females to get mammary tumors, but males can get them as well. Spaying females can greatly reduce the occurrence of tumors. If you notice a swelling or lump anywhere on your rat, take him or her to the vet as soon as you can.

Tumors are often quite easily removed. The veterinarian performing the surgery sometimes doesn’t even need to cut into the body cavity. It’s better to remove a mass before it gets so large it impedes your rat’s mobility or impinges on an internal organ. Also, if the tumor is cancerous, it’s even more important to remove the tumor as soon as possible so wide margins* can be achieved which aid in preventing further the spread of the disease.

Some tumors grow quite rapidly. Your veterinarian will often do a fine needle aspirate to ascertain what types of cells are in the mass. Most often, tumors are benign. Even if they’re cancerous, removing them (with wide margins) can many times prevent the cancer from spreading.Noras Tumor2

Removing tumors is usually a very safe procedure. I wouldn’t hesitate to have a tumor removed on any of my rats unless they were extremely old or had respiratory or heart problems. There are so many people who don’t realize just how easy it is to have the tumors removed.

You will not need to withhold food before surgery. If the veterinary hospital’s receptionist tells you to fast your rat when confirming your surgery, s/he may not have been trained properly. However, if the veterinarian tells you to withhold food, then you know this particular vet is not knowledgeable and you’ll need to find a different vet. Dogs and cats (and humans) need to fast since they run the risk of vomiting during a procedure and can aspirate their vomit, resulting in respiratory problems. Rats cannot vomit. The structures of their esophagus and stomach and the way their muscles coordinate do not allow them to vomit. Rats need to eat prior to surgery to maintain their blood sugar and to stay hydrated.

Once the tumor has been removed, your vet should send your rat home with pain medication such as buprenorphine or metacam. Your rat will either have sutures or the area could be closed up with surgical glue. Recovery should be fairly quick with your rat returning to normal energy and appetite within 1-2 days.

Your veterinarian may ask if you’d like the tumor to be sent in to a lab for analysis. This is called a histopath. It does cost extra money and your veterinarian can help you decide whether or not learning the results will help in how you take care of your rat. A histopath can Tumor3ddetermine if it’s cancer or not as well as how wide the margins are. As mentioned earlier, the majority of tumors are benign (especially mammary tumors) so, if you’re on a tight budget, you may decide to decline a histopath. Also, in most cases a fine needle aspirate will have already been done.

However, if your veterinarian recommends it and you can afford it, a histopath will allow you to know for sure what type of tumor was removed. If you do find out the tumor is cancerous and you learn the margins weren’t very wide, you’ll know your rat may have a recurrence of the cancer. Having the histopath done also gives your veterinarian more information as to what medications and treatment plans will be most effective for your rat in the future.

*Wide Margins: The ideal surgery will include removal of a significant portion of tissue around the perimeter of the mass in addition to the actual tumor.  The tissue removed from areas adjacent to the tumor is the “margin”. Wide margins are helpful because they indicate all the entire tumor was removed. This is especially important if the tumor was cancerous. The detection of the size of the margin is part of the histopathology report. 

Note: Male rats’ testicles have been mistaken as “tumors” by new rat owners. If you see two large “tumors” underneath your male rat’s tail, those are probably his testicles not tumors.

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