"Canine Stomach Tumors" TUMOR TIDBITS, A BIWEEKLY EMAIL NEWSLETTER FROM GULF COAST VETERINARY ONCOLOGY Number 69; September 13, 2002. ======================================================================= THIS WEEK'S TUMOR TIDBIT: CANINE STOMACH TUMORS ======================================================================= WHO IS "Murphy"? Two weeks ago I saw Murphy, a 10 yr old Miniature Schnauzer, in our clinic presenting with signs of weight loss and projectile vomiting. The primary care veterinarian had performed complete laboratory work (complete blood count, serum biochemistry analysis, urinalysis), survey radiographs of the chest cavity, and an abdominal ultrasound. The primary reason for referral was a mass observed on ultrasound in the gastric region along with enlarged lymph nodes caudal to the stomach. The laboratory work was generally unremarkable and consistent for a dog with poor appetite, vomiting and dehydration. The chest xrays were normal in appearance. WHAT DID WE FIND ON OUR EXAM? A repeat ultrasound examination was performed in our hospital, a needle cytology sample obtained from the gastric mass and lymph nodes, and an in- house evaluation was highly suggestive of carcinoma. The dog went to surgery, the mass was removed, and samples of the mass submitted for histologic examination. A diagnosis of gastric adenocarcinoma was confirmed and the dog at present is doing very well. WHAT DO WE KNOW ABOUT STOMACH CANCER IN DOGS? In a recent issue of the Journal of the American Animal Hospital Association (2002 Mar-Apr; 38(2):157-64), Drs. Swann and Holt from the Veterinary Hospital at the University of Pennysylvannia reported on a retrospective study that described 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. In this study the beneficial effects of chemotherapy alone or adjuvant chemotherapy were 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. It appears from this report that surgical resection does alleviate gastric outflow obstruction in the immediate postoperative period. WHAT DID WE DO FOR MURPHY? In our dog, we began Adriamycin chemotherapy 1 week after surgery and our plan is to continue Adriamycin every 2 weeks for a total of 5 treatments, then follow using a maintenance protocol of monthly Vincristine and weekly Cytoxan chemotherapy, along with daily Doxycycline (for antiangiogenesis) and Piroxicam (immune support as a COX2 inhibitor). Our intent is to chemically control the growth of cancer cells to induce remission of the nodes (Adriamycin therapy) and keep the remaining post-surgical microscopic disease "dormant" or in remission using the other medications. In our experience, Murphy should have few complications during therapy and have a good chance for 1 year remission and a reasonable chance for 2 years. SUGGESTED READING * Veterinary Oncology, From "The Practical Veterinarian Series". By Hahn KA. Butterworth-Heinemann Press, 2002. ======================================================================= Hope this info helps and don't hesitate to call us Gulf Coast Veterinary Oncology! Kevin A. Hahn, DVM, Phd, Diplomate ACVIM (Oncology), drhahn@gcvs.com Janet K. Carreras, VMD, Diplomate ACVIM (Oncology), drcarreras@gcvs.com Glen K. King, DVM, MS, Diplomate ACVR (Radiology & Radiation Therapy), drking@gcvs.com Gulf Coast Veterinary Diagnostic Imaging & Oncology 1111 West Loop South, Suite 150, Houston, TX 77027 P: 713.693.1166 F: 713.693.1167 W: www.gcvs.com