Cancer is a leading cause of death among companion animals, with many cases diagnosed at advanced stages when clinical signs have appeared, and prognosis is poor. Emerging diagnostic technologies, including Artificial Intelligence (AI)-enhanced imaging, liquid biopsies, molecular diagnostics, and nematode-based screening, can improve early detection capabilities in veterinary medicine. These tools offer non-invasive or minimally invasive methods to facilitate earlier detection and treatment planning, addressing the limitations of traditional diagnostics, such as radiography and tissue biopsies. Recent advancements in comparative oncology, which leverage the biological similarities between human and companion animal cancers, underscore their translational value in improving outcomes across species. Technological advances in genomics, bioinformatics, and machine learning are driving a shift toward precision medicine, enabling earlier detection, personalized treatments, and monitoring of disease progression. Liquid biopsy testing detects circulating tumor DNA and tumor cells, providing actionable insights into tumor genetics without invasive procedures. Imaging systems enhance diagnostic precision, offering consistent and accurate tumor identification across veterinary practices, while portable innovations like