Fifty-five dogs with lymphoma were treated using a doxorubicin-based sequential combination chemotherapy protocol. Complete response, partial response, and no response were seen in 46,4, and 5 dogs, respectively. The overall median remission duration and survival times were 36 and 51 weeks, respectively. Age, sex, weight, World Health Organization stage, World Health Organization substage (i.e., a = not ill, b = ill), serum calcium concentration, blood urea nitrogen concentration, breed, and protocol alteration secondary to toxicity were evaluated for prognostic significance. Univariate analysis of prognostic factors identified sex, World Health Organization substage, and serum calcium as statistically significant (P I .05) variables for both survival and remission duration. Upon multivariate analysis, only substage (P = .036) was a significant prognostic factor for remission duration, whereas, both substage (P = .006) and sex (P = .005) were significant prognostic factors for survival. times were shown; however, several reports of doxorubicin used as a sole chemotherapeutic agent for treatment of lymphoma, for reinduction of remission in failed lymphoma, or in combination with other drugs for induction or maintenance of lymphoma have indicated results comparable to several cyclic combination protocol^.^-'^ One study has shown an overall median survival time of 5 1 weeks when doxorubicin was included in a combination chemotherapy protocol.' There is controversy in the literature regarding prognostic factors for canine lymphoma. These factors have been summarized in a recent review article.I6 Previous studies have used univariate analysis, and therefore have not accounted for confounding variables when evaluating for prognostic factors. Multivariate analysis would help eliminate confounding variables.Because doxorubicin is effective against lymphoma, we evaluated the effect of including doxorubicin in a sequential combination chemotherapy protocol on survival time and remission duration. Additionally, several factors were evaluated for prognostic significance using multivariate analysis. Materials and MethodsFifty-five dogs with lymphoma underwent sequential combination chemotherapy without any prior treat- 289

Results suggested that a high percentage of cats with lymphoma will respond to treatment with the University of Wisconsin-Madison chemotherapy protocol. Age, sex, anatomic form, and clinical stage were not significantly associated with duration of first response or survival time, but initial response to treatment was.

Hemangiosarcomas confined to the skin and underlying muscle were surgically excised in 2 5 dogs. Tumors were staged based on their histological location (ie, dermal, hypodermal, and deep). Dermal (stage I) hemangiosarcomas were small, most commonly ventral-abdominal or prepucia1 in location, and were associated with prolonged survival times (median survival, 780 days). Tumors with hypodermal (stage II) and underlying muscular involvement (stage 111) were grouped together because of their larger size, bruise-like appearance, lack of anatomic predilection, emangiosarcoma (HSA, malignant hemangioendo-H thelioma, angiosarcoma) is a neoplasm arising from endothelial cells.' It occurs more frequently in the dog than in any other species, with a reported prevalence of 0.3% to 2.0%.2-6 The spleen is the most frequent primary site of involvement; however, primary dermal and hypodermal HSAs are also common, accounting for 14% of these tumors in There are few reports specifically describing the biological behavior of HSAs originating from cutaneous (ie, dermal or hypodermal) tissues in dogs."-" Most cutaneous forms are included in the literature as part ofa large series ofdogs with HSAs, regardless of the tissue of rigi in.^,','^-^^ Frequently, it is difficult to distinguish cutaneous HSA from HSA of other origins (eg, splenic, right atrial) in these reports. The presence of 1 or more cutaneous HSAs may represent metastatic disease rather than a primary lesion, and therefore has frequently been associated with a poor prognosis." Cutaneous HSAs are rare in humans, in whom they have been described as highly invasive neoplasms with a high rate of local recurrence.23 They occur almost exclusively in I of 3 separate clinical presentations: ( 1) previously irradiated skin; ( 2 ) the face and scalp of elderly patients; and (3) the chronic lymphedematous extremity, often in postmastectomy patients.24 The long-term prognosis for these patients is extremely poor, with a reported median survival time of only 20 months after radical surgxal excision and adjuvant radiotherapy.25 The only two prognostic factors identified in humans with cutaneous HSA include the size of the lesion at the time of diagnosis and the degree of lymphocytic infiltration around the t~m o r .~~,~~ Tumors less than 5 cm in diameter and those with lymphocytic infiltrates are associated with longer survival times.",26Vascular stasis, radiation therapy, trauma, and sun exposure have been suggested as predisposing factors for the development of cutaneous HSAs in humans.26 Solar radiation has been proposed to play a causal role in spontaneously occumng dermal HSAs in dogs.'' In addition, HSAs have been experimentally induced with UV radiation in dogs2'The purpose of this study is to describe the clinical characteristics and survival times in dogs with primary cutaneous HSAs treated by surgical excision. Materials and MethodsRecords of the University of Florida and The Ohio State University veterinary pathology services were reviewed to identify all pribiological beha...

BackgroundGastrointestinal stromal tumors (GISTs) are uncommon intestinal neoplasms in the dog. Literature regarding adjunctive therapy for GISTs in dogs is sparse. High‐risk GISTs in humans respond to tyrosine kinase inhibition in the adjuvant setting.ObjectivesTo review cases of toceranib phosphate use in dogs with GISTs and provide initial assessment of possible biological activity. A secondary aim was to evaluate patient and tumor characteristics for possible prognostic value.AnimalsTwenty‐seven dogs with confirmed GISTs based on histopathology and immunohistochemistry treated with toceranib.MethodsRetrospective study in which cases of toceranib use in dogs with GIST were solicited using the American College of Veterinary Internal Medicine Oncology and Small Animal Internal Medicine listservs.ResultsFive of 7 dogs with gross disease experienced clinical benefit (71%; 3 complete responses, 1 partial response, 1 stable disease). These included 2 dogs with durable responses after toceranib discontinuation. Median progression‐free interval (PFI) in dogs with gross disease was 110 weeks (range, 36‐155 weeks). Median PFI in dogs with microscopic disease was 67 weeks (range, 9‐257 weeks). Metastasis at diagnosis (P = 0.04) and high mitotic index (P < 0.001) were associated with shorter PFI in toceranib‐treated dogs.Conclusions and Clinical ImportanceBiological activity of toceranib is evident in dogs with gross disease. Metastasis of GIST at diagnosis, as well as high tumor mitotic index, was associated with shorter PFI in toceranib‐treated dogs. Larger studies are needed to define postsurgical risk and refine the use of toceranib in dogs with gross and microscopic GIST.

Stereotactic radiosurgery (SRS) involves precise delivery of a single large dose of radiation to a designated tumor target. This report describes use of SRS in combination with a frameless stereotactic localization system to treat 11 dogs with appendicular osteosarcomas. Five dogs were treated with SRS alone; 6 were treated with a combination of SRS and chemotherapy. Overall median survival time was 363 days (range, 145 to 763 days), with 6 dogs still alive 90, 142, 234, 367, 633, and 763 days after SRS. Limb function was good or excellent in all 6 dogs that were still alive. Results in these dogs suggest that SRS may be a viable option for dogs with appendicular osteosarcoma, with the potential to provide long-term local tumor control and improvement in limb function, especially when combined with chemotherapy. Because of the destructive nature of osteosarcoma and limitations of SRS, dogs with tumors that are small and have caused minimal bone destruction would likely be the best candidates for this procedure.