Thrombocytosis and tumour distribution predict outcome in dogs with hepatocellular carcinoma: A multi‐institutional retrospective analysis

Abstract Background Hepatocellular carcinoma (HCC) is the most common canine hepatobiliary tumour. This study aimed to determine which criteria influenced outcome of HCC in a modern population of dogs across eight institutions. Methods The medical records of 106 dogs with HCC were retrospectively reviewed. Inclusion criteria included histopathologic diagnosis of HCC and adequate follow‐up. Prognostic factors were evaluated for their effect on median survival time (MST). Results Massive HCCs (80%) were most common and had the longest MST (1000 days), which was significantly longer than nodular or diffuse forms. Bloodwork abnormalities at diagnosis included elevated liver enzymes (94%), thrombocytosis (26%) and neutrophilia (15%). Thrombocytosis and neutrophilia were associated with shorter median survival compared to dogs with normal values (629 vs. 1000 days; 583 vs. 976 days, respectively). MST for 104 dogs treated surgically was longer than medically treated dogs (945 vs. 265 days). Chemotherapy administered in 14 dogs did not improve outcome. Limitations The retrospective nature and multi‐institutional study design limited the standardisation of diagnostics, treatment and follow‐up. Conclusions Consistent with previous studies, massive HCC carries a better prognosis than nodular or diffuse forms. Surgery remains the mainstay of treatment for massive HCC. Thrombocytosis or neutrophilia at diagnosis may predict worse outcomes.