Breed predispositions and malignancy analysis for canine tumors: A multicenter histopathological retrospective study from Central Italy.

Animal Cancer Registries (ACRs) enhance our understanding of oncology by providing insights into epidemiologic and clinical trends and fostering comparative research. This study analyzed a large dataset of canine tumors, evaluating their distribution and malignancy profiles by breed, sex, neuter status, age, and district of origin. Histologically diagnosed tumors from two pathology-based ACRs in central Italy (2008-2023) were coded using Vet-ICD-O-canine-1. Logistic regression assessed the influence of variables on tumor behavior, modeled as a binary outcome ("malignant" vs "benign"). Of 26,218 tumors, 41.6 % were benign and 58.4 % malignant. Malignancy risk increased by 8 % per year of age. Females had higher risk of malignancy (OR = 2.16; 95 %CI 2.04-2.29). Neuter status didn't affect malignancy risk (OR = 1.02; 95 %CI 0.96-1.09) but influenced risk for specific tumor groups. Highest malignancy risk was in Dogo Argentinos (OR = 2.18; 95 %CI 1.49-3.25), Rottweilers (OR = 2.00; 95 %CI 1.56-2.57), Pugs (OR = 1.99; 95 %CI 1.38-2.92), and Doberman Pinschers (OR = 1.79; 95 %CI 1.35-2.40); lowest in West Highland White Terriers (OR = 0.54; 95 %CI 0.38-0.76), Siberian Huskies (OR = 0.66; 95 %CI 0.49-0.90), Cocker Spaniels (OR = 0.69; 95 %CI 0.58-0.83), and Poodles (OR = 0.72; 95 %CI 0.60-0.87). Potential new predispositions emerged in Cane Corsos (lymphomas, basal cell tumors, histiocytic tumors) and Maremma Sheepdogs (odontogenic, adnexal, and skin appendage neoplasms). This study confirms known patterns, reveals novel risk factors, and highlights the importance of multicenter collaboration in identifying high-risk oncology patients.