Palliative Chemotherapy Shows Promise for Feline Carcinoma of Unknown Primary

Carcinoma of unknown primary, or CUP, is one of those diagnoses that makes even seasoned veterinary professionals pause. Despite advanced imaging, histopathology, and immunohistochemistry, the original tumor site remains elusive. In human oncology, CUP is relatively common and notoriously challenging, accounting for a notable percentage of new cancer diagnoses and carrying a guarded prognosis. In veterinary medicine, especially in cats, documented cases are few, leaving clinicians with limited guidance and a lot of tough conversations.