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Senior dogs face many health problems such as arthritis and cognitive decline, but cancer is, unfortunately, one of the most common. Although one in four dogs will develop cancer at some point in their life, this disease will strike almost half of all dogs over the age of 10. According to the Veterinary Cancer Society, it’s the leading cause of death in senior dogs.

That means it’s important to keep a watchful eye on your senior dog’s health and behavior. Ensure they receive regular veterinary care and remain alert for symptoms so you can get help for your pet as soon as possible before the disease spreads. With treatment options similar to those for people, there’s hope your dog can defeat the disease.

Cancer Symptoms in Dogs

Cancer is the development and out-of-control growth of abnormal cells which can move throughout the body, spreading into and destroying normal tissues. There are many types of cancer, and the signs and symptoms vary based on the type and location of the illness. Therefore, it’s important to monitor your dog’s overall health and consult your veterinarian if you see anything out of the ordinary, either physically or behaviorally. Here are some of the signs to watch for:

  • Unusual lumps and bumps. These growths could appear anywhere, so be sure to examine your entire pet regularly during petting sessions or as part of your dog’s grooming routine.
  • Sores or open wounds that don’t heal.
  • Weight loss or loss of appetite.
  • Discharge from any opening in the body, such as the nostrils, mouth, or anus. This includes bleeding, vomiting, and diarrhea.
  • Bad odor. Tumors in the mouth, nose, or anus can lead to offensive smells.
  • Lack of interest in exercise and play, or a decrease in stamina. This can be your dog slowing down from old age, but it can also be one of the first signs of illness.
  • Mobility issues like limping or stiffness. Although this can indicate arthritis, it can also be caused by nerve, muscle, or bone cancer.
  • Problems breathing or going to the bathroom. If your dog is wheezing, having trouble urinating, or straining to poop, an immediate trip to the veterinarian is in order.

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None of these signs guarantee your dog has cancer, so don’t panic. Other illnesses or issues could be to blame, including relatively harmless ones like benign fatty tumors. But the sooner your dog is diagnosed, the sooner life-saving treatment can begin.

Diagnosing Cancer in Dogs

If you suspect cancer in your dog, how will your vet confirm your fears? They will likely perform a complete wellness check including blood work and urinalysis. That will allow them to assess organ function and rule out other conditions. They may also conduct scans such as an ultrasound or CT scan to see the position and size of the tumor. Finally, they will need a sample of the tissue in question for examination under a microscope. This will be done with a biopsy. One type of biopsy is a fine-needle aspirate where a very thin needle is inserted into the tumor to withdraw a sample of the cells.

Your vet may also refer you to a specialist known as a veterinary oncologist. These experts focus on cancer development and treatment. You can find a board-certified veterinary oncologist through Vet Specialists. Don’t be afraid to ask your vet for a referral or second opinion. You want to ensure your dog is getting access to the best care available including clinical trials for new treatments.

Dog Cancer Treatments

There are three main avenues of treatment for cancer in dogs, and they are the same as those for humans: surgery, radiation therapy, and chemotherapy. The treatment your vet or veterinary oncologist suggests will vary based on your dog’s diagnosis, such as the type or stage of cancer.

Although the purpose of surgery is to remove a tumor, it’s not always the best option for every cancer. More cancer may be cured with surgery than with other treatments, but if the tumor has microscopic fingers that surgery can’t remove, cancer will likely return. That may make radiation or chemotherapy necessary. Also, examination of the cancerous tissue after it has been removed will help answer questions such as whether the tumor will grow back and whether it will spread, and therefore what additional steps should be taken.

Radiation therapy is the use of high-dose ionizing radiation to damage the DNA of cancer cells, thereby killing them. It can shrink a tumor or even destroy it entirely. This treatment is most effective in tumors with rapidly dividing cells, and it can be used on its own or as part of a combination of treatments. It can help shrink a tumor before surgical removal or limit the growth of cancer cells left behind after surgery.

Chemotherapy is the use of drugs to kill or slow the growth of cancer cells. These drugs can be administered in pill form or given intravenously and are often developed from natural sources like plants or bacteria. As with radiation, chemotherapy can be used before or after surgery or as a treatment on its own.

Finally, there are potential new treatments on the horizon. A newer and still evolving treatment called immunotherapy boosts a dog’s own immune system to fight off cancer. Like the more traditional treatments, immunotherapy might work best in combination with other treatments. And there are various cancer vaccines undergoing testing such as one for osteosarcoma, a bone cancer.

Golden Retriever getting comforted while lying on a table at the vet.
alexsokolov/Getty Images Plus

Caring for a Dog With Cancer

Side effects from cancer treatments vary. After surgery, your dog will need to rest and leave the incision site alone. Radiation therapy side effects are usually temporary and can include soreness or discomfort at the site of treatment. And chemotherapy side effects are much milder in dogs than in people, with 70 percent of dogs having few if any issues. The key with all treatments is to keep your dog comfortable and to maintain the best quality of life possible.

Adjunct therapies can help with side effects. For example, acupuncture may help with pain management and appetite. Be sure to consult a veterinarian knowledgeable about alternative treatments and report every supplement and alternative therapy you’re using to ensure there aren’t any conflicts with the main course of treatment. Cancer is a terrifying diagnosis, but you can be your pet’s best advocate. Thanks to specialized treatments your dog can battle the condition while maintaining a high quality of life.

This article is intended solely as general guidance, and does not constitute health or other professional advice. Individual situations and applicable laws vary by jurisdiction, and you are encouraged to obtain appropriate advice from qualified professionals in the applicable jurisdictions. We make no representations or warranties concerning any course of action taken by any person following or otherwise using the information offered or provided in this article, including any such information associated with and provided in connection with third-party products, and we will not be liable for any direct, indirect, consequential, special, exemplary or other damages that may result, including but not limited to economic loss, injury, illness or death.

Related article: How to Bring Your Dog Back Into Training After a Break
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