What is cancer in pets? - Explanation and common tumors

Cancer in pets is an umbrella term for conditions in which cells divide uncontrollably. This can lead to the formation of tumors that crowd out surrounding tissue or spread to other organs. Although cancer is often associated with serious illness, it is important to distinguish between benign and malignant tumors.

In this article, we explain exactly what cancer is, what the difference is between benign and malignant, and which tumors are most common in dogs and cats.

What is a tumor?

A tumor is an abnormal growth of cells. These cells divide faster or in a more uncontrolled way than normal. Tumors can develop anywhere in the body, for example in the skin, organs, bones, or blood.

Benign versus malignant tumors

• Benign tumors: grow slowly, do not invade surrounding tissue, and do not spread. They can, however, be problematic due to their size or location.
• Malignant tumors (cancer): grow faster, invasively penetrate surrounding tissue, and/or can spread (metastasize) to other organs such as the lungs, liver, or lymph nodes.

Common tumors in dogs

• Skin tumors (mast cell tumors, histiocytomas, lipomas)
• Mammary gland tumors (especially in unspayed female dogs)
• Lymphoma (cancer of the lymph nodes)
• Bone cancer (osteosarcoma, especially in large breeds)
• Hemangiosarcoma (a tumor arising from blood vessels, often in the spleen or heart)

Common tumors in cats

• Mammary gland tumors (often malignant, especially in unspayed female cats)
• Lymphoma (often in the intestines or chest, sometimes related to FeLV/FIV)
• Squamous cell carcinoma (skin cancer, especially on the nose and ears in white cats)
• Fibrosarcoma (connective tissue tumor, sometimes at injection sites)
• Mast cell tumors (in cats, usually found in the skin or spleen)

How is cancer diagnosed?

A cancer diagnosis is made based on:

• Physical examination and palpation of lumps
• Imaging: X-rays, ultrasound, CT or MRI scans
• Cytology: examining cells under a microscope obtained via a needle aspirate
• Biopsy: removing a piece of tissue for histological examination

Treatment options

Treatment of cancer in pets depends on the type of tumor, its location, and its stage:

• Surgery: removal of the tumor. Tumor margins depend on the type of tumor. Depending on the tumor type, the lymph nodes may also be removed
• Chemotherapy: medications that kill or slow cancer cells. Blood is regularly monitored during treatment to check for adequate white blood cell counts and to assess organ function
• Radiation therapy: local treatment of tumors or as a follow-up treatment
• Immunotherapy: activating the body's own immune system

In some cases, palliative care is chosen to improve quality of life.

Prognosis

The prognosis for cancer varies widely. Some tumors respond well to treatment and can even be fully cured, while others carry a poor prognosis. Early detection and prompt treatment significantly increase the chances of success.

Want to know more?

Read more about oncology and the various treatment options available at Nesto. Our specialized veterinarians have extensive experience in diagnosing and treating cancer in pets.

Frequently asked questions (FAQ)

What is the difference between a tumor and cancer?

Not every tumor is cancer. Only malignant tumors that spread are called cancer.

Which tumors are common in dogs?

Skin tumors, mammary gland tumors, lymphoma, bone cancer, and hemangiosarcoma.

Which tumors are common in cats?

Mammary gland tumors, lymphoma, squamous cell carcinoma, fibrosarcoma, and mast cell tumors.

How is cancer diagnosed in my pet?

Through physical examination, imaging, and tissue examination such as needle aspirates or biopsies.

Can cancer in pets be treated?

Yes, depending on the type of tumor, surgery, chemotherapy, radiation therapy, and other treatments are possible.