Page 1347 - Clinical Small Animal Internal Medicine

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141 Cancer of the Esophagus and Stomach 1285

postoperative complications. Esophageal surgery is prone with metastatic or nonresectable GISTs had a favorable
VetBooks.ir to serious complications, including stricture, dehiscence, response with the use of imatinib (Gleevec®), a selective
tyrosine kinase inhibitor. This resulted in stabilization or
infection, regurgitation, esophagitis, and fistula forma-
tion. This has been attributed to many factors, including
tyrosine kinase inhibitors are currently approved for use
esophageal movement during swallowing, high wound resolution of disease for a median of 20 months. Two
tension, lack of a serosal layer and the presence of a seg- in veterinary medicine (Palladia™, Pfizer, and Kinavet‐
mental blood supply to the esophagus. After esophageal CA1®, AB Science) and may also prove to be effective
surgery, use of a gastrostomy tube is recommended to against GISTs in dogs.
decrease the amount of motion occurring at the surgical
site and facilitate mucosal healing. En bloc resection is
associated with the best prognosis but submucosal resec- Prognosis
tion to debulk the mass without a full resection and anas-
tomosis can be an acceptable treatment with successful The prognosis for esophageal cancer is very poor. These
outcomes for leiomyomas/low‐grade leiomyosarcomas. cancers are usually not diagnosed until they are advanced,
Short‐term palliation can be achieved with placement of by which time they are typically difficult or impossible to
a gastric or percutaneous endoscopic gastrostomy tube. resect and often are metastatic. Photodynamic therapy
In people, palliation is commonly achieved by the place- has been attempted, but with modest results. The median
ment of an endoluminal stent. An interventional tech- survival for dogs with esophageal sarcoma following sur-
nique to perform this procedure in veterinary patients is gery and doxorubicin chemotherapy was 267 days.
potentially possible. Interestingly, in many cases, the cause of death was sec-
Radiation therapy is of limited use due to the tissue ondary to aspiration pneumonia due to abnormalities in
tolerance of the surrounding structures. In humans, esophageal motility.
radiation therapy alone is used as a palliative treatment The prognosis for gastric adenocarcinoma is poor fol-
for esophageal tumors or following surgery. Results lowing the onset of clinical signs. Without treatment,
following radiation therapy alone are short‐lived and animals usually succumb to their disease within 1–3
universally poor unless done in combination with months. Surgery affords the best chance for improving
surgery and chemotherapy. the long‐term prognosis. Animals that survive the perio-
Complete surgical excision is the treatment of choice perative period have reported median survival times of
for gastric adenocarcinomas but is typically complicated 4–6 months but a small number of long‐term survivals of
due to advanced disease, predilection for the lesser cur- greater than 36 months have been reported. Most
vature, antrum and pylorus, extensive gastric involve- patients eventually succumb due to recurrent or meta-
ment and/or metastasis to regional lymph nodes and static disease. Leiomyosarcomas and GISTs have a
liver. Surgical approaches such as a Billroth I (partial gas- slightly better prognosis with reported median survival
trectomy and gastroduodenostomy) or Billroth II (partial times of 6–12 months. Surgery can be curative for benign
gastrectomy and gastrojejunostomy) can provide imme- lesions that are completely resected. EPCs have an
diate relief of gastric outflow obstruction and clinical excellent prognosis with surgery and chemotherapy.
improvement in the early postoperative period. Careful Information on long‐term follow‐up is lacking in the lit-
staging prior to pursuing surgery is recommended to erature, but a dog treated with surgery and doxorubicin
insure the morbidity associated with the procedure can chemotherapy was alive and asymptomatic 30 months
be justified. post diagnosis. Less than 10% of cases of gastric MCT,
The beneficial effects of chemotherapy alone or in the regardless of treatment(s) utilized, lived beyond six
adjuvant setting for gastric adenocarcinoma are largely months. Occasionally, there are cases of gastric MCT
unknown. Reported chemotherapy protocols utilizing that appear to do significantly better than this, suggest-
5‐fluorouracil, 5‐fluorouracil and cyclophosphamide, ing there may be a less aggressive variant of this disease.
5‐fluorouracil, doxorubicin and cyclophosphamide (FAC This supports the palliative use of systemic chemother-
protocol) or cis‐platinum appeared to provide some clin- apy in patients with minimal clinical symptoms and a
ical benefit in a few cases. Comparatively, 80% of people reasonable quality of life.