Objective—To compare associations between vaccine types and other injectable drugs with development of injection-site sarcomas in cats.
Animals—181 cats with soft tissue sarcomas (cases), 96 cats with tumors at non-vaccine regions (control group I), and 159 cats with basal cell tumors (control group II).
Procedures—Subjects were prospectively obtained from a large pathology database. Demographic, sarcoma location, basal cell tumor, and vaccine and other injectable history data were documented by use of a questionnaire and used to define case, control, and exposure status. Three control groups were included: cats with sarcomas at non-vaccine sites, cats with basal cell tumors, and a combined group of cats with sarcomas at non-vaccine sites and cats with basal cell tumors. χ2 tests, marginal homogeneity tests, and exact logistic regression were performed.
Results—In the broad interscapular region, the frequency of administration of long-acting corticosteroid injections (dexamethasone, methylprednisolone, and triamcinolone) was significantly higher in cases than in controls. In the broad rear limb region, case cats were significantly less likely to have received recombinant vaccines than inactivated vaccines; ORs from logistic regression analyses equaled 0.1, with 95% confidence intervals ranging from 0 to 0.4 and 0 to 0.7, depending on control group and time period of exposure used.
Conclusions and Clinical Relevance—This case-control study measuring temporal and spatial exposures efficiently detected associations between administrations of various types of vaccines (recombinant vs inactivated rabies) and other injectable products (ie, long-acting corticosteroids) with sarcoma development without the need to directly measure incidence. These findings nevertheless also indicated that no vaccines were risk free. The study is informative in allowing practitioners to weigh the relative merits and risks of commonly used pharmaceutical products.
Objective—To determine whether particular vaccine
brands, other injectable medications, customary vaccination
practices, or various host factors were associated
with the formation of vaccine-associated sarcomas
Animals—Cats in the United States and Canada with
soft tissue sarcomas or basal cell tumors.
Procedure—Veterinarians submitting biopsy specimens
from cats with a confirmed diagnosis of soft tissue
sarcoma or basal cell tumor were contacted for
patient medical history. Time window statistical analyses
were used in conjunction with various assumptions
about case definitions.
Results—No single vaccine brand or manufacturer
within antigen class was found to be associated with
sarcoma formation. Factors related to vaccine administration
were also not associated with sarcoma
development, with the possible exception of vaccine
temperature prior to injection. Two injectable medications
(long-acting penicillin and methyl prednisolone
acetate) were administered to case cats more frequently
than to control cats.
Conclusions and Clinical Relevance—Findings do
not support the hypotheses that specific brands or
types of vaccine within antigen class, vaccine
practices such as reuse of syringes, concomitant
viral infection, history of trauma, or residence
either increase or decrease the risk of vaccineassociated
sarcoma formation in cats. There was
evidence to suggest that certain long-acting
injectable medications may also be associated
with sarcoma formation. (J Am Vet Med Assoc 2003;223:1283–1292)