"Vaccination Sarcomas in Dogs" TUMOR TIDBITS, A WEEKLY EMAIL NEWSLETTER FROM GULF COAST VETERINARY ONCOLOGY Number 103; August 8, 2003. ======================================================================= THIS WEEK'S ANNOUNCEMENTS FROM GULF COAST VETERINARY ONCOLOGY We’re still recruiting canine patients for our ongoing clinical trial evaluating the role of growth hormone in the prevention and correction of anemia in cancer patients. The qualification examination is provided at no cost and eligible dogs may have all services provided at no charge (including any appropriate surgery, radiation, or chemotherapy) for 4 to 6 months. Please check our web site for additional clinical trials that are available or call our offices in Houston (713.693.1166) or San Antonio (210.822.1913) for additional information. Want to download a free copy of our latest Oncology Handbook? Visit www.gcvs.com/oncology. We also provide free email cancer consultations. ======================================================================= THIS WEEK'S TUMOR TIDBIT: Vaccination Sarcomas in Dogs ======================================================================= Do Vaccine-Associated Sarcomas occur in Dogs? Most of us in oncology, and others, believe they do but little proof exists. In this Tumor Tidbit, I've included below the abstracts of two reports, one in dogs (2003) and one in cats (1996), that describe the differences that exist between sarcomas in vaccination and non-vaccination sites. To date, these are the only two "smoking gun" reports in the veterinary literature. Currently I serve on the AVMA Council of Biologic and Therapeutic Agents (COBTA) as the Small Animal Practice Representative. Many in our profession have voiced concerns regarding proper vaccination schedules in cats and in dogs, whether the terms "injection" or "vaccine-associated" should be used, and are there factors that may predict the onset or prognosis for an affected pet animal. I am very proud of the work performed to date, albeit slow, by COBTA and others in these important issues. Continued discussion in our profession, the Center of Veterinary Medicine, and the pharmaceutical industry needs to continue and focus on issues of fact, not fiction. This Tumor Tidbit is not intended to solve these issues but to add further fact to the discussion. Canine Study Abstract Fibrosarcomas at Presumed Sites of Injection in Dogs: Characteristics and Comparison with Non-vaccination Site Fibrosarcomas and Feline Post-vaccinal Fibrosarcomas. Vascellari M, Melchiotti E, Bozza MA, Mutinelli F. J Vet Med A Physiol Pathol Clin Med. 2003 Aug;50(6):286-91. Fifteen fibrosarcomas, surgically excised from presumed sites of injection in dogs, and 10 canine fibrosarcomas excised from sites not used for injection were histologically and immunohistochemically compared with 20 feline post-vaccinal fibrosarcomas. Canine fibrosarcomas from presumed injection sites were of grade I (3), of grade II (4) and grade III (8). Two fibrosarcomas from non-injection sites were of grade I, four of grade II and four of grade III. Feline samples were classified as grade I (2), grade II (4) and grade III (14). All fibrosarcomas from presumed injection sites of both species showed lymphocytic inflammatory infiltration located at the tumour periphery, while two canine fibrosarcomas from non-injection sites showed perivascular inflammatory infiltration within the neoplasm. All samples were immunohistochemically examined for vimentin, smooth muscle actin, muscle specific actin and desmin expression. All tumours were positive for vimentin. Ten canine fibrosarcomas from presumed injection sites and all feline samples contained cells consistent with a myofibroblastic immunophenotype. Aluminium deposits were detected in eight canine fibrosarcomas from presumed injection sites and 11 feline post-vaccinal fibrosarcomas by the aurintricarboxylic acid method. The present study identifies distinct similarities between canine fibrosarcomas from presumed injection sites and feline post-vaccinal fibrosarcomas, suggesting the possibility of the development of post-injection sarcomas not only in cats, but also in dogs. Feline Study Abstract Feline fibrosarcomas at vaccination sites and non-vaccination sites. Doddy FD, Glickman LT, Glickman NW, Janovitz EB. J Comp Pathol. 1996 Feb;114(2):165-74. A retrospective study of 195 feline sarcomas diagnosed histologically between July 1988 and June 1994 showed that 170 (87.2%) were fibrosarcomas. Cats with vaccination site (VS) fibrosarcomas were younger (8.6 +/- 3.9 years; median = 8 years) than cats with non- vaccination site (NVS) fibrosarcomas (10.2 +/- 4.7 years; median = 11 years) (P = 0.03), but there was no such association with breed, sex, or "neuter status". Microscopical features more characteristic of VS fibrosarcomas than of NVS fibrosarcomas were (1) subcutaneous location (P < 0.001), (2) necrosis (P < 0.001), (3) inflammatory cell infiltration (P < 0.001), (4) increased mitotic activity (P < 0.02), (5) pleomorphism (P < 0.001), and (6) variability in the density of the extracellular matrix (P < 0.001). When these data were fitted to a logistic regression model, younger age (P = 0.003), subcutaneous location of the fibrosarcoma (P = 0.0002), and the presence of inflammation (P = 0.017) were more characteristic of VS fibrosarcomas than of NVS fibrosarcomas. The study showed that in the absence of any vaccination history, the age of a cat, coupled with certain histological characteristics (e.g., tumour location in skin, and inflammation), may help in distinguishing VS fibrosarcomas from NVS fibrosarcomas. The characteristic histological features of VS fibrosarcomas, such as necrosis, increased mitotic activity and pleomorphism, are those of aggressive tumours. ======================================================================= As always, we hope this info helps and don't hesitate to call or email 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 ======================================================================= Copyright © 2003, Gulf Coast Veterinary Oncology