Feline Gastrointestinal Adenocarcinoma Study Guide

Overview and Clinical Importance

Gastrointestinal adenocarcinoma is the second most common intestinal neoplasm in cats after lymphoma, representing 20-35% of all feline GI tumors. These are highly aggressive, locally invasive malignancies with high metastatic potential that typically affect older cats (mean age greater than 10 years). The prognosis is generally poor despite aggressive treatment, making early recognition and appropriate staging critical for NAVLE success.

Epidemiology and Risk Factors

Age and Breed Predisposition

Feline intestinal adenocarcinoma predominantly affects geriatric cats with a mean age of 10-12 years at diagnosis. Siamese and other Asian breeds (Tonkinese, Burmese) appear overrepresented, accounting for approximately 14% of cases in some studies, suggesting a possible genetic predisposition. Male cats may have a slightly higher incidence, though this is inconsistent across studies.

Anatomic Distribution

Pathophysiology and Tumor Behavior

Growth Pattern and Local Invasion

Feline GI adenocarcinomas exhibit characteristic annular, stenosing growth that encircles the intestinal lumen circumferentially, causing progressive luminal narrowing and mechanical obstruction. The tumors demonstrate transmural invasion through all intestinal layers with frequent extension through the serosa. Serosal infiltration occurs in approximately 85-87% of cases, often associated with carcinomatosis (peritoneal seeding), which is present in 81% of surgical cases.