ABSTRACT
The concept that animals may serve as sentinels of environmental hazards is not new. Nowadays, it has been widely recognized the important role that pets have in the field of comparative oncology. Cancer epidemiologic data are the foundation for prevention and control; therefore, Cancer Registries represent a fundamental tool that systematically collects, and stores validated and comprehensive data. In Veterinary Medicine, cancer registries have unfortunately been sporadic, short-lived, and lacked communication and collaboration. Therefore, there is little up-to-date information available on the incidence of different types of cancer in companion animals anywhere in the world. The purpose of this review is to provide a brief overview of the currently and globally active veterinary cancer registries. Moreover, a special focus will be dedicated to a novel web-based cancer registration system implemented in the Department of Veterinary Medicine in Naples, Italy. This platform was designed and conceived for the implementation of the regional Animal Cancer Registry, for a constant evaluation of the frequency, the incidence and/or the prevalence of cancer cases in pets and for advancement in the field of veterinary comparative oncology.

IMPACT STATEMENT
Animal Cancer Registries are a fundamental instrument for advancement in the field of veterinary comparative oncology. Epidemiologic data on cancer in companion animals can help to identify new environmental hazards.