Integrated Oncology Services

Lymphoma (lymphosarcoma, LSA) is a cancer of the lymphocytes (white blood cells) most commonly originating in the lymph nodes (lymph glands), although it may affect any organ, including spleen, liver, intestines, and skin. Fortunately, most (~90%) patients treated with combination chemotherapy undergo clinical remission (no visible evidence of cancer) for extended periods of time.

Mammary tumors in dogs are extremely common and approximately 50% of them are malignant. Mammary tumors are more common in intact than in spayed females. In fact, spaying before the first or second heat cycle significantly reduces the risk of developing mammary tumors in dogs. The median age for a presentation is 10 - 11 years. Dogs fed a high-fat diet or who are overweight at one year of age are at increased risk of developing mammary gland tumors. Appropriate early treatment, even if the tumor is malignant, is often curative.

Soft tissue sarcomas (STSs) consist of a variety of tumors that arise from mesenchymal cells. Tumors included in this group are fibrosarcomas, peripheral nerve sheath tumors, and hemangiopericytomas. They typically appear as firm, subcutaneous (under the skin) masses, which may be located on the extremities, trunk, or head and neck. They usually are slow-growing tumors but may also come up quite quickly. These tumors are locally invasive and are not likely to go to other sites (metastasize).

Lymphoma is a cancer of the lymphocytes (white blood cells) most commonly occurring in the gastrointestinal tract or mediastinum (chest) of cats, although it may affect any organ, including lymph nodes, spleen, liver, kidneys, nose, and skin. Fortunately, most patients treated with combination chemotherapy go into clinical remission (no visible evidence of cancer) for extended periods of time.

Quality of life for cats with lymphoma on chemotherapy, as judged by the owners, usually is excellent.

Mammary tumors are among the most common tumors in the cat; Domestic Shorthairs and Siamese may have higher incidence rates than other breeds. The mean age at presentation is 10 to 12 years. Most affected cats are intact females; however, the disease is occasionally seen in spayed females and, rarely, in male cats. Several reports have documented a strong association between the use of contraceptives and the development of benign or malignant mammary masses in cats.

Surgery is the most widely used treatment for mammary neoplasms in cats; it is used alone or in combination with chemotherapy. Radical mastectomy (i.e., removal of all glands on the affected side) is the surgical method of choice because it significantly reduces the chance of local tumor recurrence. Early diagnosis and treatment is vital in cats with mammary tumors.

Injection-site sarcomas (ISS) are also referred to as fibrosarcoma. They are mesenchymal tumors that are locally invasive and have a low to moderate chance of spreading to other sites (metastases). These tumors develop in areas where cats have received injections, mainly vaccines. Common locations include the interscapular (between the shoulder blades) region, the flank region, and the rear legs. These tumors tend to be firm, subcutaneous masses that are not freely movable.

If you have concerns or questions about a lump on your cat, we recommend that you consult with your veterinarian. If your cat has been diagnosed with an ISS, treatment options may include a combination of surgery, radiation therapy, and chemotherapy; consultation with an oncologist is advised.

Mast cell tumors (MCTs) are one of the most common skin tumors in dogs. Although some breeds are predisposed, such as Boxers and Golden Retrievers, MCTs can develop in dogs of any breed. Middle-aged to older dogs have a higher risk of developing MCTs, but young dogs can also be affected.

The treatment is variable depending on the histopathologic grade and extent of disease. When MCTs can't be surgically removed, radiation therapy is recommended, although in some cases chemotherapy may have similar effects.