Currently, no effective treatments exist for veterinary patients with nonresectable liver cancer. Because of poor responses or complications with systemic chemotherapy and radiation therapy, veterinary oncologists typically treat these patients with supportive care.
Similar treatment difficulties in people with nonresectable hepatocellular carcinomas have led to investigation into regional, or liver-directed, therapies including intra-arterial chemotherapy delivery, transarterial embolization (TAE), transarterial chemoembolization (TACE) and ablation therapies (typically chemical or thermal).
TACE involves placing a small catheter in the femoral artery. Under fluoroscopic guidance, the catheter is advanced up the aorta and into the hepatic artery feeding the tumor, and a full dose of systemic chemotherapy and embolic particles or microspheres is injected to obstruct blood flow to the tumor. More recently, the development of drug-eluting beads has enabled 100 to 400 times the concentration of chemotherapy to be achieved within the tumor compared with the same dose given intravenously (systemically). See how this experimental therapy helped this terrier.
This patient had undergone previous abdominal surgery in which the nonresectable liver mass was biopsied. The surgery report described the mass as adhered to the portal vein, pancreas and bile duct, originating from the base of the liver and attaching to the body wall, right lateral and quadrate liver lobes and gallbladder. Biopsy results at that time were consistent with a well-differentiated hepatocellular carcinoma. Since these tumors demonstrate poor biological responses to systemic chemotherapy and radiation of the liver is not performed, historical standard therapy involves benign neglect and supportive care until these tumors either metastasize or, more commonly, rupture.
A CT angiogram (Figure 1) indicated that this patient was a good candidate for the drug-eluting bead TACE procedure, which was performed the next day. A combination of 1 ml of drug-eluting beads was mixed with doxorubicin (30 mg/m2) to allow the beads to absorb the chemotherapy. A 2- to 3-cm surgical incision was made in the groin to permit the placement of a vascular sheath within the femoral artery. A catheter was advanced under fluoroscopic guidance into the celiac artery. Superselective access was gained by using a 2.4-Fr microcatheter in order to minimize nontarget (normal liver parenchyma) embolization and to achieve maximal concentrations of chemotherapy and drug-eluting beads within the actual tumor.
The dog recovered uneventfully and was discharged from the hospital the next day with prednisone, amoxicillin-clavulanate, tramadol, ondansetron and omeprazole. The results of repeat complete blood counts one, two and three weeks after the TACE procedure were unremarkable.
TACE has been shown in a number of human randomized clinical trials to be associated with prolonged survival times when compared with systemic therapies.1,2 Drug-eluting beads slowly elute the doxorubicin over weeks to months within the tumor, resulting in less toxicity to patients, most of which show no side effects from the chemotherapy (such as immunocompromise or gastrointestinal toxicoses associated with systemic delivery).3
Postembolization syndrome, which is characterized by general malaise, fever, nausea and abdominal discomfort, occurs in many people after TACE. The syndrome is generally self-limiting and well-managed with supportive care such as anti-inflammatories, antinausea medications, antibiotics, pain medications and gastroprotectants. In addition, drug-eluting bead TACE therapy has been shown to result in fewer side effects such as postembolization syndrome and better results (for large tumors) than standard chemoembolization.4 It is unclear if animals experience postembolization syndrome, but we currently treat them empirically with the same medications just in case.
A fully funded study is currently looking at the use of this technique in dogs with nonresectable liver tumors (hepatocellular carcinoma), which covers the cost of three treatments and staging during the treatment process, including CT angiography. For more information about this study, please contact us at (212) 329-8816.
A video of the TACE procedure can be viewed at www.amcny.org/node/341#Liver_Cancer. For more case studies and to see how interventional radiology and interventional endoscopy can benefit patients, visit www.amcny.org/interventional-radiology-endoscopy.
Dr. Berent is the director of Interventional Endoscopy Services in the Department of Diagnostic Imaging at The Animal Medical Center in New York City. Dr. Weisse is the director of Interventional Radiology Services in the Department of Diagnostic Imaging at The Animal Medical Center in New York City.
1. Llovet JM, Real MI, Montana X, et al. Arterial embolisation or chemoembolisation versus symptomatic treatment in patients with unresectable hepatocellular carcinoma: a randomised controlled trial. Lancet 2002;359(9319):1734-1739.
2. Lo CM, Ngan H, Tso WK, et al. Randomized controlled trial of transarterial lipiodol chemoembolization for unresectable hepatocellular carcinoma. Hepatology 2002;35(5):1164-1171.
3. Varela M, Real MI, Burrel M, et al. Chemoembolization of hepatocellular carcinoma with drug eluting beads: efficacy and doxorubicin pharmacokinetics. J Hepatol 2007;46(3):474-481.
4. Lammer J, Malagari K, Vogl T, et al. Prospective randomized study of doxorubicin-eluting-bead embolization in the treatment of hepatocellular carcinoma: results of the PRECISION V study. Cardiovasc Intervent Radiol 2010;33(1):41-52.