“Stella Beans”, a sweet and wiggly middle aged kitty, presented to the CWVS Oncology service in February 2019 for evaluation of a mass on the left side of her chest wall. Her family veterinarian suspected a feline injection site sarcoma, a rare type of cancer that can develop in cats at the site of a previous injection such as a vaccine or a microchip. A CT scan was performed to determine the extent of the mass. The external portion of the mass was just the “tip of the iceberg” as the internal portion of the mass extended into both the abdomen and chest and was resting against her lungs and liver. A needle core biopsy was performed and confirmed the suspected diagnosis of an injection site sarcoma.
Stella then had surgery to remove the mass where Dr. King removed a portion of the left chest wall including ribs 9 – 13 and the lateral portion of the diaphragm. Stella’s body wall was reconstructed with prolene mesh which was secured to the surrounding muscles and remaining diaphragm. She spent three days in the CWVS ICU to ensure adequate pain control and recovery before being discharged to home care.
The pathology report showed a high grade spindle cell sarcoma. This type of tumor would be expected to have rapid regrowth and a higher risk of spread to other body sites (metastasis). Unfortunately the surgical margins were incomplete, meaning we were not successful in removing all of the tumor. This is common for injection site sarcomas, especially in difficult areas such as the body wall. Post-operative radiation treatment and post-operative chemotherapy were discussed with Stella’s owners. As there are no radiation oncology facilities for pets in B.C., Stella’s owners elected to treat with chemotherapy.
Once her surgical incision was healed, Stella returned to CWVS Oncology for treatment with chemotherapy. She received a total of five doses of an injectable chemotherapy medication called doxorubicin. Chest x-rays performed before her first and fourth doses of chemotherapy did not show any evidence of cancer recurrence.
Because Stella finds hospital visits stressful her owners decided not to bring her in for routine rechecks after her chemotherapy protocol was finished. They report that she is very happy, comfortable, and clinically well at home.
Canada West Veterinary Technician Amanda Brackett prepared a detailed case report on Stella’s situation that was submitted to the Veterinary Cancer Society’s 2019 Case Report Competition. Her presentation was selected for presentation at the society’s annual conference in Houston, and after presenting she was awarded first place in the competition! Congratulations Amanda!
You can read the full clinical case study here: Feline vaccine associated sarcoma: staging and treatment