Cattle, horses, cats, and dogs with microscopically confirmed multiple primary tumors were reported to the Veterinary Medical Data Program, a system to collect, store and retrieve veterinary clinical information. Of 261 1 tumors diagnosed prior to, concurrent with, or subsequent to other tumors during the period studied, 2361 were in 1062 dogs and 250 were in 120 other animals in all other species categories. The 604 multiple primary malignancies (two or more malignant tumors in one animal) were similarly distributed, by species, with 512 in dogs and 92 in all other species combined. The total number of multiple tumors reported in dogs closely approximated a theoretic model of random distribution, but several site-pairs of tumors seemed to occur excessively; one pair (mammary tumors and tumors of internal female organs) might parallel a similar excessive occurrence in women, suggesting a possible spontaneous tumor model for the latter.
Cancer 40:1845-1848, 1977.
TUDY OF MULTIPLE TUMORS IN DOMESTIC ANI-
S mals, attractive because of the possibility of etiologic linkage of similar or dissimilar tumors, has been frustrated by lack of an adequate data base. However, recent availability of a file of information about 17,000 spontaneous primary tumors in domestic animals and a matching clinic-hospital reference population permits us to begin identifying some of the factors that seem to be associated with the occurrence of multiple tumors.
Methods
The case series, composed of animals with microscopically confirmed multiple primary tumors, was compiled from the abstracts of medical records submitted to Veterinary Medical Data Program (VMDP), a system to collect, store and retrieve veterinary clinical information.' The tumor series and the reference population (which consisted of animals brought to any of the clinics for any reason) were from reports sent by 13 schools of veterinary medicine