Canine gastric adenocarcinoma and leiomyosarcoma: a retrospective study of 21 cases (1986-1999) and literature review.

This retrospective study describes the clinical course, treatment, and outcome of 21 dogs with gastric adenocarcinomas (n=19) and leiomyosarcomas (n=2). Medical records from 1986 to 1999 were reviewed for signalment, weight, diagnosis, tumor location, clinical signs, radiographic imaging procedures, surgical procedures, chemotherapy, duration of follow-up monitoring, outcome, cause of death, metastatic rate, metastatic sites, and method of detection of metastasis. Fourteen of 19 (74%) dogs with gastric adenocarcinomas had metastasis. Metastatic sites included gastric lymph nodes, omentum, liver, duodenum, pancreas, spleen, esophagus, adrenal glands, and lungs. Both cases of a gastric leiomyosarcoma had metastatic disease involving the liver (n=2) and duodenum (n=1). Surgery, consisting of either a Billroth I or a gastrojejunostomy, provided immediate relief of the gastric outflow obstruction and clinical improvement in the early postoperative period. The beneficial effects of chemotherapy alone or adjuvant chemotherapy are still unknown. Recurrence of clinical signs 3 days to 10 months after surgery caused all owners to elect euthanasia. The long-term prognosis for most cases of gastric adenocarcinomas and leiomyosarcomas is poor because of the presence of advanced disease. Surgical resection, however, does alleviate gastric outflow obstruction in the immediate postoperative period.