Therapies for equine cancer are few and far between, but a veterinary oncologist from Colorado State University (CSU) thinks equine tumors could be treated with non-steroidal anti-inflammatory drugs (NSAIDs). Doug Thamm, VMD, Dipl. ACVIM, an assistant professor in oncology at CSU’s College of Veterinary Medicine & Biomedical Sciences, presented research at the American College of Veterinary Internal Medicine’s Forum on June 1 in Louisville, Ky. He described how some tumors he examined expressed the enzyme cyclooxygenase-2 (COX-2). COX-2-inhibiting NSAIDs could be appropriate for treating these growths.

COX-2 is an enzyme that stimulates the production of prostaglandin E2, a protein that might stimulate growth and establishment of a tumor while helping the tumor evade the immune system. "The pharmacologic inhibition of COX-2 with NSAIDs has been associated with antitumor activity in various human and canine malignancies, including canine oral squamous cell carcinoma (SCC)," said Thamm.

He and his colleagues examined 14 sarcoids and 39 SCC, and they found that COX-2 was expressed in two of 14 sarcoids (14%) and 35 of 39 SCC (90%). Sarcoids are generally considered less harmful than SCC.

"Based on this information, a majority of equine SCC appear to express COX-2 and thus might be responsive to treatment with NSAIDs," Thamm said, noting that further study of NSAID therapy for equine tumors is warranted