GENERAL CONSIDERATIONS

General Considerations

•LSA is the most common gastric tumor in cats (solitary or multicentric) and most are FeLV negative

•sex predisposition: males

•gross appearance: discrete mass or diffuse gastric wall diffusion

Clinical Signs

•clinical signs are caused by gastric outflow obstruction, altered motility, or chronic blood loss secondary to tumor necrosis and ulceration

•progressive vomiting is common and may contain fresh or digested blood

•weight loss may be caused by poor digestion, protein malnutrition, or cancer cachexia

Laboratory Tests

•laboratory tests and survey radiographs are usually unrewarding

•microcytic hypochromic anemia is common with chronic blood loss and occult blood may be detected in feces

•increased liver enzymes may be seen with hepatic metastasis or obstruction of the common bile duct

Imaging

Radiographs

•positive- or double-contrast radiographs: gastric tumors can appear as a mass effect, ulcer crater, delayed gastric emptying with poor motility, and delayed adherence of contrast material to an ulcerated tumor

Ultrasonography

•ultrasonographic findings include transmural thickening of the gastric wall with loss or altered layering (poor echogenic outer and inner lining with hyperechoic central zone)

•other findings include tumor location, ulceration, extension through gastric wall, and lymphadenopathy

Endoscopy

•gastroscopy allows direct visualization and guided biopsy

•several biopsies should be performed as superficial ulceration, necrosis, and inflammation is common

•submucosal masses are difficult to biopsy and false-negative results are common

Other Imaging Techniques

•CT and MRI

TREATMENT

Surgery

•surgery is possibly solitary feline gastric LSA but complicated by advanced stage at presentation, frequent metastasis, difficult access, and debilitated animal

•lymph node metastasis is variable and all abdominal lymph node should be evaluated for staging purposes

•curative resection should be attempted if disease is localized to the stomach

•surgical techniques: Billroth I or II or palliative bypass procedures

•Billroth I or II provides immediate relief of gastric outflow obstruction and clinical improvement in early postoperative period

•Billroth II (partial gastrectomy and gastrojejunostomy) or complete gastrectomy (with biliary by-pass) are very extensive surgeries with high morbidity and minimal survival advantage

•partial gastrectomy preferred in humans due to better nutritional status and quality of life and radical gastrectomy does not improve survival time

•palliative gastrojejunostomy for inoperable or metastatic lesions but associated with significant morbidity including anastomotic ulcers

Chemotherapy

•gastric LSA does not respond well to conventional chemotherapy protocols and chemotherapy may not be required following surgical resection of solitary gastric LSA in cats

Prognosis

•prognosis depends on surgical excision, tumor type and grade, and presence of metastatic lesions

•gastric LSA: MST 40 weeks with Madison-Wisconsin protocol and 15.5 months with prednisolone-chlorambucil