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
GASTRIC LYMPHOSARCOMA