Injection site-associated sarcoma in the cat: treatment recommendations and results to date.

PRACTICAL RELEVANCE: Feline injection site-associated sarcomas (FISSs) have been the cause of much controversy and concern since they were first reported in the early 1990s. While not solely associated with vaccination, there are implications for vaccination sites and schedules and, while guidance has been published, this appears to be permeating only slowly through to general practice. CLINICAL CHALLENGES: Up to one-quarter of cats with this difficult condition have metastatic lung involvement. The mainstay of treatment is aggressive surgery, but even in cases where full excision with clean margins is achieved, tumour recurrence is anticipated in about one-third of cases. The role of radiotherapy and chemotherapy as adjuvant treatments has yet to be clearly defined. PATIENT GROUP: FISSs are often seen in younger cats, with a peak presentation at 6-7 years and a second peak at 10-11 years. EVIDENCE BASE: This review summarises the diagnosis and management of FISS with reference to the latest published treatment results. It focuses on surgical excision but also covers adjuvant radiotherapy and chemotherapy, and gives median survival times for the different treatment approaches.