Cancer morbidity in Croatian cats: Retrospective study on spontaneously arising tumors (2009-2019).

One of the current leading causes of death in pet cats is neoplasia. The scarcity of data on tumor prevalence in cats from south-eastern Europe led to this retrospective study which reports an abundant collection of tumors diagnosed in cats living in Croatia. Archived histopathology findings (diagnosis, cell origin, and biological behavior), and epidemiological data (breed, sex, age, and anatomical site of the tumor) of the cats diagnosed with at least one tumor were collected and statistically analyzed. For the research, 2338 archived feline samples, obtained from 2009-2019, have been reviewed. In 659 samples (28.1%) one or more tumors were diagnosed. Tumors have most often affected non-pedigree cats, cats between 7 and 15 years of age, and female cats. Most tumors showed malignant behavior (85.7%). The most frequent diagnoses were mammary adenocarcinoma, lymphoma, and squamous cell carcinoma. Regarding origin, most samples were epithelial (46.9%), but mesenchymal (28.7%) and lymphoid tumors (17.0%) were also frequently found. Tumors most often occurred in the skin and subcutis, mammary gland (in females), digestive system, and hemolymphatic system (in males). Statistical analysis did not reveal breed, sex, and age predisposition, but female animals and non-pedigree cats were significantly more likely to develop malignant tumors. This detailed study gives insight into the most frequent tumors that occur in cats from Croatia, and the data reported here is likely applicable to other countries. This data will contribute to clinical veterinary oncology, as it presents the most extensive tumor index of cats in south-eastern Europe.