2017 ACVIM Forum Research Abstract Program

Serious complications were overall uncommon following resection of gastrointestinal lymphoma with the majority of cases found to survive the peri-operative period. Given the significantly longer survival times of cats with large intestinal lymphoma, it may be reasonable to recommend surgical removal for cats with solitary lymphoma tumors in this location. The purpose of this study was to solicit data regarding current clinical use of toceranib in dogs with gastrointestinal stromal tumors (GIST) to provide initial assessment of biologic activity. The American College of Veterinary Internal Medicine Oncology and Small Animal Internal Medicine listservs were used to solicit data pertaining to cases in which toceranib was used to treat canine GIST. Case data from 28 dogs with histopathogically confirmed GIST were received from 17 participating institutions. Dogs undergoing treatment other than surgical excision prior to toceranib were excluded. Clinical benefit (CB) was observed in 93% (26/ 28; 24 complete response [CR]/no evidence of disease [NED] , 1 partial response [PR] , 1 stable disease [SD] ). All dogs with microscopic disease experienced CB (21/21; 21 NED), while 71% (5/7; 3 CR, 1 PR, 1 SD) with gross disease experienced CB. Median duration of treatment in dogs experiencing CB was 36 weeks (1-159). At the time of data submission, 8/26 responding dogs were still receiving treatment and an additional 4/26 were experiencing continued NED following completion of prescribed therapy. In dogs with CB, the median toceranib dose was 2.6 mg/kg (0.5-3.5) and in 81% (21/26) was given three days per week. Treatment was well-tolerated with 57% (16/28) experiencing adverse events, a majority of which were Grade 1 or 2 gastrointestinal toxicities. Biologic activity of toceranib is evident in studied dogs; however, prospective studies are needed to refine the role of toceranib in treatment of GIST in microscopic and gross disease settings. Regulatory T cells (Tregs) play an integral role in suppression of inflammation and the maintenance of immunological tolerance. In addition, Tregs infiltrate into a variety of tumor tissues and thereby suppress antitumor immunity. However, data on the association between tumor-infiltrating Tregs and prognosis in dogs with various tumors are limited. The purpose of this study was to examine the number of tumor-infiltrating Tregs and their association with prognosis in dogs with solid tumors.