Age at Tumor Diagnosis in 14,636 Canine Cases from the Pathology-Based UNIPI Animal Cancer Registry, Italy: One Size Doesn't Fit All.

Simple Summary: Cancer is the leading cause of death in adult dogs. All dogs would benefit from early diagnosis, but there are no official guidelines for cancer screening in pets, although many different diagnostic tools for cancer detection are being studied. With our analysis of 14,636 cases, we aimed to determine the age of cancer diagnosis for dogs. Malignant tumors were diagnosed more often than benign neoplasms in older dogs. Intact females, large-sized, brachy-/dolichocephalic, and purebred dogs developed cancer at a younger age, but wide differences between breeds were noted. The earliest age at diagnosis was recorded for lymphomas and mast cell tumors. Due to the wide phenotypic and genetic variability of canines, breed-based screening schedules should be devised. Cancer is the most common cause of death in adult dogs. All dogs would benefit from early diagnosis, but there are no specific guidelines regarding the schedule of cancer screening in companion animals. The aim of this study was to retrospectively evaluate the age at diagnosis in Italian oncological canine patients. A total of 14,636 canine histologically confirmed neoplastic cases were coded according to the Vet-ICD-O-canine-1 and stratified by malignancy, sex, neutering status, breed, cephalic index, body size, and tumor type. Differences in age distribution were analyzed and the influence of these variables on the time of first malignancy diagnosis was assessed using an event history analysis model. The median age at diagnosis for benign and malignant tumors was 9 and 10 years, respectively. Intact and purebred dogs were diagnosed earlier, but the median age differed significantly by breed. The earliest age at diagnosis was recorded for lymphomas and mast cell tumors. The model showed an accelerating effect of large size, brachy- and dolichocephaly, and sexual integrity in female dogs on the time of malignancy diagnosis. Our results confirm that a "one-size-fits-all" approach to cancer screening is not accurate in dogs and provide relevant data that may lead to the establishment of breed-based screening schedules. [ABSTRACT FROM AUTHOR]