What Are the Signs a Dog Has Cancer?
Cancer can affect dogs in many ways. Symptoms will vary depending on where it starts, how fast it grows, and whether it spreads. The most common signs of cancer in dogs include:
- Lumps or Bumps: New growths on or under the skin that get bigger or don’t go away.
- Sores That Don’t Heal: Open wounds that stay the same or get worse over time.
- Weight Loss: Losing weight without a change in diet or activity.
- Changes in Eating/Drinking: A sudden change in appetite or skipping meals often. Sudden increase or decrease in drinking water.
- Tiredness or Low Energy (Lethargy): Sleeping more than usual or not wanting to play or go for walks.
- Trouble Breathing, Peeing, or Pooping: Straining, coughing, or accidents in the house can be signs of something serious.
- Limping, Stiffness, or Swelling: Difficulty walking, climbing stairs, or getting up from lying down. Swelling in the legs, neck, or abdomen.
- Bleeding or Discharge: Blood or fluid coming from the nose, mouth, or private areas.
- Acting Different: Mood or behavior changes, like hiding more, becoming grumpy, or acting nervous.
It’s impossible to list all the signs of cancer in dogs. If you’re worried or notice changes in your dog’s health or behavior, talk to your vet. Catching cancer early could save your dog’s life. And, getting pet insurance BEFORE there’s a problem can help you save money on the cost of treatment should your dog develop cancer.
How is Canine Cancer Diagnosed?
Diagnosing cancer in dogs often starts with the owner noticing unusual signs like lumps, weight loss, or behavioral changes. A veterinarian will typically begin with a physical exam and then recommend diagnostic tests to confirm cancer and determine how advanced it is.
Common diagnostic tools used to identify canine cancer include:
- Fine-needle aspiration (FNA): Collects cells from a lump or tumor for microscopic evaluation.
- Biopsy: Involves removing a tissue sample for a definitive cancer diagnosis and grading.
- Histopathology: A pathologist (a doctor who specializes in examining tissue samples under a microscope) examines the biopsy tissue to confirm cancer, identify the type, and assess how aggressive it is (grading).
- Blood Tests: Can reveal organ function, anemia, or markers that suggest cancer is present.
- X-rays and Ultrasound: Help visualize internal tumors or assess if cancer has spread.
- CT Scan or MRI: Provides detailed images of tumors in complex areas like the brain or chest.
- Urinalysis: Assesses kidney function and detects abnormalities that may indicate cancer.
Grading refers to how different the cancer cells look compared to normal cells and how quickly the cancer may grow. A lower grade typically means the tumor is slower-growing and less aggressive, while a higher grade indicates a more aggressive tumor that may spread more quickly. Staging, which we’ll discuss next, refers to how far the cancer has spread in the body.
Staging Cancer in Dogs
Once cancer is confirmed, staging helps determine how far it has progressed. Staging is based on tumor size, lymph node involvement, and whether the cancer has metastasized (spread). This process guides treatment decisions and helps predict prognosis.
General cancer stages in dogs:
- Stage 0: Cancer cells are present but confined to a small area.
- Stage I: A small tumor is present but has not spread to lymph nodes or other tissues.
- Stage II: The tumor is larger or has started to affect nearby lymph nodes.
- Stage III: Cancer has invaded nearby tissues or multiple lymph nodes.
- Stage IV: The cancer has metastasized to distant organs like the lungs or liver.
Once your dog has been diagnosed with cancer, you’ll need to discuss treatment options with your vet.
How is Cancer Treated in Dogs?
Treating cancer in dogs depends on several factors. The type of cancer, its location, the stage of the disease, and the overall health of the dog all play a role. Treatment options may involve a combination of surgery, radiation therapy, chemotherapy, and alternative therapies. The goal is to either remove or shrink the tumor, slow the cancer’s spread, or manage symptoms to improve the dog’s quality of life.
Common cancer treatments for dogs include:
- Surgery: Often the first choice, surgery aims to remove the tumor or cancerous tissue. If the cancer is localized, surgery can be curative.
- Radiation Therapy: Uses high-energy rays to target and shrink tumors, typically when surgery isn’t an option or if the cancer has spread.
- Chemotherapy: Uses drugs to kill cancer cells or slow their growth. Chemotherapy may be used when the cancer has spread or to shrink a tumor before surgery.
- Immunotherapy: Helps the dog’s immune system recognize and attack cancer cells, much like how vaccines help the body fight infections. This treatment is still relatively new but shows promise in some cases.
- Targeted Therapy: Involves drugs that specifically target cancer cells without harming normal cells.
- Palliative Care: Aims to make dogs with advanced cancer as comfortable as possible. It usually focuses on relieving pain and symptoms to help improve their quality of life.
- Alternative Therapies: Some pet owners may explore complementary treatments like acupuncture or herbal supplements to help manage symptoms, but these should always be discussed with a veterinarian.
A veterinary oncologist can tailor the treatment plan based on the individual dog’s needs, and the approach may change as the cancer progresses or the dog responds to treatment.
What Causes Cancer in Dogs?
While the exact cause of cancer in dogs is not always known, several factors can lead to its development. Like in humans, cancer in dogs can occur due to genetics, environmental influences, and certain lifestyle factors. Understanding these risks can help pet owners take preventive measures to potentially reduce their dog’s risk.
Known and potential causes of cancer in dogs include:
- Genetics: Some breeds are more prone to specific types of cancer. For example, Golden Retrievers, Boxers, and Rottweilers are known to have higher rates of certain cancers.
- Age: Older dogs are more likely to develop cancer, as the body’s cells change over time. Cancer rates increase as dogs age due to longer exposure to environmental and genetic factors.
- Environmental Toxins: Exposure to chemicals, such as pesticides, herbicides, and certain household cleaners, may increase the risk of developing cancer in dogs. Secondhand smoke has also been linked to higher cancer rates in pets.
- Diet and Obesity: A poor diet or obesity can impact the immune system and overall health, potentially increasing cancer risks.
- Radiation and Sun Exposure: Prolonged exposure to UV radiation from the sun can increase the risk of skin cancers, particularly in dogs with light-colored fur or thinner coats.
- Viruses and Infections: Some viral infections, like the canine papillomavirus, can increase the likelihood of developing certain cancers, such as squamous cell carcinoma.
- Chronic Inflammation: Long-term (chronic) inflammation happens when the body keeps trying to heal itself over time. Whether from infection, injury, or other causes, this constant repair process can sometimes cause cells to grow abnormally, leading to cancer.
While some of these factors may increase a dog’s risk, it’s important to understand that cancer can still develop in dogs with no known risk factors. Regular veterinary check-ups and early detection are key to improving outcomes.
Cancer is Tough, But So Are You and Your Dog
Hearing that your dog has cancer is heartbreaking, but you’re not alone. Advances in veterinary care mean that many cancers can be treated or managed to give your dog more time—and a better quality of life. Whether your dog needs surgery, chemotherapy, or simply comfort care, working closely with your veterinarian is the best way to make informed, compassionate decisions.
If you notice any changes in your dog’s behavior, energy level, or physical appearance, don’t wait. Early detection can make all the difference. And if you’re worried about the cost of treatment, pet insurance can help ease the financial burden, especially if you enroll before any health issues arise.
Your dog counts on you to be their voice and advocate. Trust your instincts, ask questions, and know that even small steps can lead to big hope.