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If your dog has been diagnosed with cancer or you suspect they may have cancer, you’ve likely turned to the internet for more information. At Aspen Veterinary Clinic, we work extremely hard to bring you the trusted information you need, especially regarding something as serious as cancer in your beloved canine companion. The mention of cancer, lump, bump, tumor, or neoplasia can cause the most sensible person to panic, but we are here to help answer your questions and hopefully calm your nerves.

If you’re looking for a highly trained veterinarian in Flagstaff, Arizona, with experience diagnosing and treating numerous forms of cancer, Aspen Veterinary Clinic is the place to be. Our team can help you navigate this difficult and potentially stressful process and provide you with the treatment option that works best for you and your pet. If you’re worried your dog may have cancer or has already been diagnosed with cancer, please call us at 928-526-2423 or visit our website at to request an appointment and we can help you through it.

Is cancer in dogs common?

Unfortunately, cancer is quite common in dogs and is probably one of the most frequently diagnosed diseases at our clinic. It is believed that cancer rates in dogs are up to 8-10 times higher than in people. In general, cancer is a disease of middle-aged to older dogs, but it can, in rare cases, affect young pets. One very interesting fact about cancer that most people don’t know is that you and I, as well as our pets, produce cancer cells throughout our entire lives, but our immune systems are trained to seek and destroy these cancer cells and cancer only occurs when these abnormal cells evade the immune system. This is why, when it comes to cancer, early detection is key. Regular wellness exams and preventative care, including blood work, can be beneficial, as our veterinarians are trained to pick up on subtle changes to your pet. If you ever notice a new lump or bump on your dog, please have your veterinarian evaluate it right away.

What are the common types of cancer in dogs?

When most people hear the word cancer in connection with a loved one, it often produces fear and anxiety. By definition, cancer is a disease caused by uncontrolled replication of abnormal cells in part of the body, typically causing a tumor. Tumors are then classified into benign tumors and malignant tumors. In general, benign tumors do not cause significant disease and do not spread throughout the body. On the other hand, malignant tumors often cause serious illness and are more likely to spread throughout the body. The only way to determine if a tumor is benign or malignant is to sample that tissue. Sometimes, this can be done with a needle and syringe, called an aspirate. These aspirates are submitted for cytology or evaluation of the cells by a pathologist. The gold standard to diagnose cancer is submitting tissue for biopsy. This requires surgical removal of part or all of a tumor and then that tissue is submitted to a pathologist for review.

We see numerous benign tumors regularly, including lipomas (commonly referred to as fatty growths) and sebaceous gland adenomas (sometimes referred to as skin tags):

  • Lipomas affect every breed but tend to be more common in overweight dogs, so keep your pup as lean as possible.
  • Sebaceous gland adenomas look like small heads of pink cauliflower and are common to Spaniels and Retrievers. Despite these tumors being benign, every new lump or bump should still be evaluated by your veterinarian and monitored closely for any changes, especially if they are growing rapidly, painful or leaking fluid or becoming ulcerated.

The common types of malignant tumors or cancers we see include lymphoma, hemangiosarcoma, osteosarcoma, soft tissue sarcoma, mast cell tumor, melanoma, squamous cell carcinoma and many more:

  • .Lymphoma is one of the most common types of cancer we see and is a cancer of the lymph system or the lymph nodes, a part of the immune system, just as in humans.
  • Hemangiosarcoma is an aggressive cancer of the blood vessels and commonly affects the spleen and/or the liver. This cancer can affect any breed, but is more common in German Shepherds, Retrievers, Pointers and working dogs.
  • Osteosarcoma is an aggressive cancer of the bones. These tumors typically affect the long bones, such as the humerus and radius of the front limb and the femur and tibia of the hindlimb. Large and giant breed dogs such as Great Danes, Mastiffs, Rottweilers, and German Shepherds are the most likely group to develop this form of cancer.
  • Squamous cell carcinomas and melanomas are common skin cancers or tumors of the skin that we see, given the high-elevation desert and the active outdoor lives we lead with our dogs. These skin cancers can affect any breed or individual that spends significant time outside, especially light-skinned and thin-coated dogs and those dogs that like to sunbathe.
  • Mast cell tumors are another form of skin cancer. This type of tumor often affects dogs with chronic allergies, such as German Shepherds, Weimaraners, Retrievers, Pitbulls, French Bulldogs and English Bulldogs.
  • Soft tissue sarcomas are malignant tumors of any breed of dog and are often confused with benign fatty tumors or lipomas because both of these tumors can affect the legs and/or body wall of dogs and are often soft to semi-firm. The main difference is soft tissue sarcomas are firmly attached to the underlying tissue, while lipomas are often more freely moveable.
  • Other common types of malignant cancers include those of the urinary bladder and those of intact male and female dogs, including testicular tumors and prostate tumors for male dogs, and mammary tumors and tumors of the ovaries and uterus for female dogs.

Given the gamut of cancers we see in dogs, please make sure to have your pet evaluated by a veterinarian if you ever find a lump or bump or if you have concerns about a tumor or cancer, as it is always easier to treat cancer while it is small and early in the disease process.

What are some signs and symptoms of cancer in dogs?

Signs and symptoms of cancer in dogs may be very obvious like a lump or bump as they age. Many of the lumps and bumps are benign, but we don’t know without checking them physically and running a straightforward test called a fine needle aspirate.

However, sometimes the signs and symptoms of cancer in dogs may be more insidious like weight loss, lack of appetite or decreased energy. As dogs are inherently stoic and won’t show signs of pain or discomfort, many dogs don't have any symptoms at all, making your dog’s annual exams so critical. During your dog’s physical exam, we palpate the abdomen, feeling for enlarged organs, masses or pain. We palpate the lymph nodes feeling for signs of enlargement. We look in your dog’s mouth and eyes. We listen to the heart and lungs. Sometimes it is necessary to perform a rectal exam. And again, we’ll recommend testing those lumps and bumps to ensure they’re benign.

Unfortunately, the weight loss and breathing difficulty you might ultimately see in your dog, are symptoms that often appear when cancer is already advanced. Annual exams are essential, but you should also be looking for anything out of the ordinary. You know your dog better than anyone, so bring them in if you find a lump or if you notice behavior changes or something else you haven’t noticed before.

Why is early detection and diagnosis of cancer in dogs so important?

The best way to cure cancer is to cut it out or surgically remove the tumor or cancer. If a tumor or cancer is detected early, while it is smaller, it is less apt to have spread, it is less traumatic to remove and the prognosis is often much better. Depending on the tumor type, surgical removal is often the only treatment necessary if it is caught early enough. Prognosis and cure rates are affected by how soon we catch the cancer and if it has spread to other organs or areas of the body.

What are some ways a veterinarian would diagnose cancer in a dog?

No two cancers are the same, so diagnosing cancer in your dog involves a combination of discussing your dog’s history, your veterinarian performing a thorough physical exam, and/or perhaps you finding a lump on your pet at home. If there is concern for cancer, your veterinarian will recommend testing a lump or bump, in addition to blood work, X-rays, and/or abdominal ultrasounds, depending on the unique circumstances of your dog.

For most lumps and bumps, we can easily determine if they are benign or malignant by simply taking a needle biopsy or aspirate to submit for cytology or evaluation of cells. This is a fast, simple, relatively painless procedure using a small needle and syringe to collect cells from a tumor to evaluate under a microscope. If the tumor is found to be benign, no additional treatment will likely be necessary. If the tumor is found to be malignant, it will be recommended to surgically remove that entire growth and submit it for biopsy.

For some lumps and bumps, it is better to remove part or all of the growth and submit for biopsy to determine if it is benign or malignant. In addition to determining if a tumor is benign or malignant, the biopsy report or histopathology gives vital information such as a diagnosis of what it is, how aggressive it is, let us know whether it had reasonable margins, whether we got it all, and its recurrence rate.

What treatment options are available for dogs with cancer?

Fortunately, in veterinary medicine, we have as many or more treatment options for dealing with cancer than humans. These treatment options include but are not limited to surgical removal, anti-cancer vaccines, chemotherapy, radiation therapy, pharmaceutical medications, anti-cancer drugs, supplements and nutrition, and palliative care. At Aspen Veterinary Clinic, we believe in providing owner’s with options when dealing with cancer and every case is treated on an individual basis. We strongly believe in education to collaborate with you as the owner, to determine what is the best possible treatment plan for your beloved dog. In some situations, chemotherapy is the best plan of attack, while surgical removal may be a better option for a different pet, while palliative care may be best in another situation. We have many excellent treatments that can prolong a high quality of life for your dog, and we will partner with you should you need to go through this process with your dog.

What are some possible side effects caused by cancer treatment?

For most of the cancer treatments listed above, there are very few side effects, but just as in humans, radiation therapy and chemotherapy can cause side effects in dogs. There are revolutionary novel cancer therapies available for your dog, that are not chemotherapy, such as anti-cancer vaccines that are generated from a tumor or piece of tumor removed from your dog. Once this tumor or piece of tumor has been processed, a custom vaccine is prepared and administered to your dog, allowing your dog’s own immune system to fight the cancer. For many of these dogs receiving an anti-cancer vaccine they have nearly zero side effects and have better outcomes than dogs being treated with maximum doses of chemotherapy. Occasionally, it is necessary to treat dogs with chemotherapy and fortunately, dogs tend to tolerate chemotherapy better than humans. Some dogs can have side effects, but it's dependent on the individual pet and it depends on what treatment is being used.

The AAHA has a comprehensive guide you can review to figure out if your dog may be at risk for cancer. If your dog has been diagnosed with cancer, you’re probably wondering what you need to know as their faithful owner, but don’t let that overwhelm you—your veterinary team is there to guide you every step.

If you have further questions about dog cancer, reach out to your veterinarian. If you live in or near Flagstaff, Arizona, we’d be happy to see your dog, confirm the diagnosis, and ensure the best possible treatment plan, You can call us directly at (928) 526-2423, or you can email us at [email protected]. Don't forget to follow us on social media Facebook, Instagram.