Page 1368 - Clinical Small Animal Internal Medicine

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1306 Section 11 Oncologic Disease

liver lobe and is therefore amenable to surgical resection. chemoembolization, immunotherapy, and antiangio
VetBooks.ir In addition to surgical resectability, other prognostic fac genic medications.
tors for massive HCC include the side of the liver affected
(right side worse than left side), pretreatment ALT and
AST elevations, and ratio of ALP:AST and ALT:AST. In Bile Duct Tumors
a paper evaluating surgery in 42 dogs with massive HCC, Initial treatment for bile duct tumors should be surgical
the median survival time after liver lobectomy was 1460 resection if they are confined to one (or two) liver lobes
days versus 270 days for dogs managed medically only. with no evidence of distant metastatic disease. The prog
Many of the dogs that underwent liver lobectomy were nosis for surgically excised adenomas is excellent with no
lost to follow‐up as they were still alive or went on to die reports of local recurrence of metastasis. On the other
of other unrelated causes at the end of the study period. hand, bile duct carcinomas carry a guarded prognosis
Right‐sided liver tumors are considered to have a worse even when surgically excised due to their high rate of
prognosis because of their proximity to the caudal vena metastasis and local recurrence. The median survival
cava, resulting in an increased risk of intraoperative time for patients with bile duct carcinoma is less than six
death. Massive HCC has a low metastatic potential months despite surgical removal. Chemotherapy can be
(0–37%) and a low recurrence rate (0–13%) after surgical considered to slow disease progression but specific
resection. chemotherapy protocols and recommendations have not
In contrast, the prognosis for dogs with nodular or dif been effectively evaluated to date in veterinary medicine.
fuse HCC is poor. This is primarily because that these There is also no known effective treatment for nodular
tumors are not typically surgically resectable due to the or diffuse tumors which cannot be surgically excised.
involvement of multiple liver lobes and they have a high
metastatic rate (93% and 100%, respectively). It is often Neuroendocrine Tumors
not possible to clinically determine if nodular and diffuse
types of HCC are secondary to intrahepatic metastasis Neuroendocrine tumors carry a poor prognosis.
prior to diagnosis or represent multiple foci of disease. Metastatic disease is documented in greater than 90% of
There is little information in the veterinary field about patients at the time of diagnosis. These tumors are often
chemotherapy for the treatment of nonresectable HCC. morphologically nodular or diffuse, limiting the ability to
In general, HCC is thought to represent a chemoresist surgically excise them. There is currently no known
ant cancer as response rates of less than 20% are reported effective treatment or chemotherapy protocol and the
in the human literature. This is thought to be secondary role of these treatments is largely unknown.
to the development of drug resistance within the hepat
ocytes, owing to their role in detoxification, or through Hepatic Sarcomas
the expression of P‐glycoprotein. A recent paper evalu
ated the chemotherapy agent gemcitabine (2’,2’‐dif Liver lobectomy is recommended if tumors are confined
luorodeoxycytidine), which has been used in human to a single liver lobe. Hepatic sarcomas, however, carry a
medicine for the treatment of solid tumors, including poor prognosis despite surgical resection due to their
HCC. This study did not find a statistical improvement high metastatic rate (86–100%). The role of chemother
in survival time for those patients with nodular, diffuse apy is still under investigation but protocols utilizing
or nonresectable massive HCC with the use of gemcit doxorubicin and ifosfamide as well as antiangiogenic
abine but the overall survival time of this small patient protocols should be considered to slow disease progres
population was 983 days. Other treatment techniques sion based on their use in sarcomas in other locations
that have been explored more recently include arterial such as the spleen.