High-Grade, Stage 2 Mast Cell Tumors: Outcome in Dogs With Local and Systemic Therapy.

Canine mast cell tumors (MCTs) have highly variable clinical behavior, and predicting outcomes in individual dogs remains challenging. Many studies combine dogs with varying tumor grades, clinical stage, or treatments, confounding those results. The purpose of this retrospective study was to determine outcome and prognostic factors in a specific subset of dogs with high-grade, stage 2, cutaneous MCTs treated with adequate local control via surgery with or without radiation therapy and adjuvant cytotoxic chemotherapy. Seventeen dogs met the inclusion criteria, and the median survival time was 259 days. Development of local recurrence, tumor location, and presence of ulceration were all associated with shorter survival times. Tumor size, mitotic count, chemotherapy protocol, lymph node classification, and radiation therapy were not significantly associated with outcome. In this study, a specific population of dogs characterized by high-grade MCTs with local lymph node metastasis who received aggressive local and systemic therapy had a median survival of about 8.5 mo. Dogs with ulcerated tumors, recurrent tumors, or tumors located on the head had a worse outcome despite aggressive therapy. These results may serve as a basis of comparison for future research exploring alternative treatment combinations in this specific population of dogs.

MRI characteristics of canine prostatic neoplasia.

Magnetic resonance imaging (MRI) has been used to evaluate dogs with suspected prostatic neoplasia, however, published studies describing MRI characteristics of canine prostatic neoplasia are currently lacking. The aims of the current retrospective case series study were to describe MRI findings of the pelvic region in dogs with a histopathologic or cytologic diagnosis of prostatic neoplasia. Retrospective analysis of these images was then performed by a board-certified veterinary radiologist for shared imaging characteristics. The most consistent characteristics were heterogeneous hyperintensity of the tumor on T2-weighted images (10/10) and short tau inversion recovery images (10/10), prostatic capsular margin distortion by the tumor (10/10), cavitations (10/10), complete effacement of the prostatic architecture (9/10), neurovascular bundle (NVB) compression or invasion (9/10), heterogeneous isointensity of the tumor on T1-weighted images (9/10), and strong contrast enhancement of the tumor (8/10). Additional features included an overlying pattern of distorted radiating striations (7/10), regional lymphadenomegaly (5/10), mineralization within the mass (5/10), urinary bladder trigone involvement (6/10), and post-prostatic urethral involvement (7/10). These findings supported the use of MRI as an adjunct imaging modality for diagnosis and therapeutic planning of prostatic neoplasia and including prostatic neoplasia as a likely differential diagnosis for dogs with these MRI characteristics.

Gender Imbalance in Authorship of Veterinary Literature: 1995 versus 2015.

Despite increasing representation of women in veterinary medicine, gender differences persist in pay and attainment of senior and leadership positions. In academia, scholarly publication is a measure of productivity and is emphasized in the promotion process. This study aimed to analyze gender differences in the authorship of veterinary research articles to understand factors that could influence women's advancement and standing in academic medicine. We hypothesized that the proportion of women authors would increase between 1995 and 2015 and be similar to employment rates of women in academia, and that gender differences would exist in authorship by species, veterinary specialty area, and role (junior versus senior author). We examined 2,086 articles published in eight prominent veterinary journals in 1995 and 2015, determined the gender of first authors, corresponding authors, and senior authors, and collected article information including study design, species, and veterinary specialty area. The proportion of women as first and corresponding author increased significantly between 1995 and 2015, and in both years studied, women authored a larger percentage of articles than the reported percentage of women working in academia. In 2015, women were first authors of 60.0% (95% CI 56.9-63.0) of articles but accounted for only 38.3% of senior authors (95% CI 33.4-43.3). Female first authors were concentrated in articles pertaining to small animal, equine, and internal medicine disciplines and under-represented among articles pertaining to livestock or surgical specialties. The gender gap in the authorship of veterinary clinical research articles has improved dramatically over the past 20 years, although gender disparities persist.

Retrospective analysis of doxorubicin and prednisone as first-line therapy for canine B-cell lymphoma.

BACKGROUND: A doxorubicin (DOX)-based chemotherapy protocol, CHOP, is the most effective treatment for canine high-grade B-cell lymphoma; however, the cost and time requirements associated with this protocol are not feasible for many pet owners. An alternative treatment option is the use of DOX, the most effective drug, in combination with prednisone. Prior studies with single-agent DOX included dogs with T-cell lymphoma, a known negative prognostic factor, which may have resulted in shorter reported survival times than if dogs with B-cell lymphoma were analyzed separately. The purpose of this study was to evaluate the outcome of dogs with high-grade B-cell lymphoma when treated with DOX and prednisone with or without L-asparaginase (L-ASP). Identification of prognostic factors was of secondary interest. RESULTS: Thirty-three dogs were included in the study; 31 dogs were evaluable for response with an overall response rate of 84%. The median progression free survival (PFS) and overall survival (OS) were 147 days and 182 days, respectively. The one-year survival fraction was 23%. No variable other than protocol completion was found to be significant for either PFS or OS including historical prognostic factors such as substage, thrombocytopenia, and body weight. CONCLUSIONS: Dogs with high-grade B-cell lymphoma treated with DOX and prednisone with or without L-ASP have similar response rates, PFS, and OS to prior studies that did not differentiate between lymphoma immunophenotype. This protocol is not a replacement for CHOP; however, it is an alternative if time and cost are factors, while providing therapeutic benefit greater than prednisone alone.

Dual Function of the IRF8 Transcription Factor in Autoimmune Uveitis: Loss of IRF8 in T Cells Exacerbates Uveitis, Whereas Irf8 Deletion in the Retina Confers Protection.

IFN regulatory factor 8 (IRF8) is constitutively expressed in monocytes and B cells and plays a critical role in the functional maturation of microglia cells. It is induced in T cells following Ag stimulation, but its functions are less well understood. However, recent studies in mice with T cell-specific Irf8 disruption under direction of the Lck promoter (LCK-IRF8KO) suggest that IRF8 directs a silencing program for Th17 differentiation, and IL-17 production is markedly increased in IRF8-deficient T cells. Paradoxically, loss of IRF8 in T cells has no effect on the development or severity of experimental autoimmune encephalomyelitis (EAE), although exacerbating colitis in a mouse colitis model. In contrast, mice with a macrophage/microglia-specific Irf8 disruption are resistant to EAE, further confounding our understanding of the roles of IRF8 in host immunity and autoimmunity. To clarify the role of IRF8 in autoimmune diseases, we have generated two mouse strains with targeted deletion of Irf8 in retinal cells, including microglial cells and a third mouse strain with targeted Irf8 deletion in T cells under direction of the nonpromiscuous, CD4 promoter (CD4-IRF8KO). In contrast to the report that IRF8 deletion in T cells has no effect on EAE, experimental autoimmune uveitis is exacerbated in CD4-IRF8KO mice and disease enhancement correlates with significant expansion of Th17 cells and a reduction in T regulatory cells. In contrast to CD4-IRF8KO mice, Irf8 deletion in retinal cells confers protection from uveitis, underscoring divergent and tissue-specific roles of IRF8 in host immunity. These results raise a cautionary note in the context of therapeutic targeting of IRF8.

Early progression during or after cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy indicates poor outcome with rescue protocols in dogs with multicentric lymphoma.

BACKGROUND: Dogs with lymphoma that fail cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy (CHOP) before completion of their protocol are commonly thought to have poor long-term outcome, but no previous studies have evaluated the effect of early relapse on progression-free interval (PFI) or overall survival time (OST) for patients undergoing rescue chemotherapy. OBJECTIVE: Correlate rescue treatment outcomes in dogs with multicentric lymphoma with outcomes after 1st-line CHOP chemotherapy. METHODS: Data were collected from 6 previous retrospective or prospective studies in 187 dogs with multicentric lymphoma that received 1st-line CHOP chemotherapy and then received either lomustine (CCNU), L-asparaginase and prednisone (LAP), or rabacfosadine (RAB, Tanovea), with or without prednisone or L-asparaginase. RESULTS: The PFI after initiation of CHOP chemotherapy was significantly associated with response rate postprogression, PFI, and postrescue survival time (ST) for both rescue protocols. Immunophenotype (B- vs T-cell) was not significantly associated with response, PFI or OST for LAP but was significantly associated with response and PFI for RAB. CONCLUSION: Dogs that experience short PFI during or after 1st-line CHOP chemotherapy had lower response rates to rescue treatment, with shorter PFI and ST. Immunophenotype did not significantly affect outcome with LAP but was associated with PFI for RAB.

Design of a randomized, placebo-controlled study evaluating efficacy and safety of a cancer preventative vaccine in dogs.

Preventative anti-cancer vaccination strategies have long been hampered by the challenge of targeting the diverse array of potential tumor antigens, with successes to date limited to cancers with viral etiologies. Identification and vaccination against frameshift neoantigens conserved across multiple species and tumor histologies is a potential cancer preventative strategy currently being investigated. Companion dogs spontaneously develop cancers at a similar incidence to those in people and are a complementary comparative patient population for the development of novel anti-cancer therapeutics. In addition to an intact immune system with tumors that arise in an autochthonous tumor microenvironment, dogs also have a shorter lifespan and temporally compressed tumor natural history as compared to humans, which allows for more rapid evaluation of safety, immunogenicity, and efficacy of cancer vaccination strategies. Here we describe the study protocol for the Vaccination Against Canine Cancer Study (VACCS), the largest interventional cancer clinical trial conducted in companion dogs to date. In addition to safety and immunogenicity, the primary endpoint of VACCS is the cumulative incidence (CI) of dogs developing malignant neoplasia of any type at the end of the study period. Secondary endpoints include changes in incidence of specific tumor types, survival times following neoplasia diagnosis, and all-cause mortality.

A multi-institutional epidemiologic study evaluating environmental risk factors for feline oral squamous cell carcinoma.

Feline oral squamous cell carcinoma (FOSCC) is an aggressive cancer in domestic cats that has no effective treatment option when advanced. Preventative or early diagnostic measures are thus crucial. FOSCC is also a model for human head and neck SCC (HNSCC); strong risk factors in HNSCC include exposure to alcohol, tobacco, areca nut, and high-risk human papillomavirus. Previous studies have identified flea collar and tobacco smoke exposure, feeding canned tuna, canned cat food and cat foods with chemical additives, living in a rural environment, and having outdoor access as risk factors for FOSCC but there was no overlap in the risk factors between studies. In our study, risks for FOSCC were evaluated in an online epidemiologic survey study in 67 cats with FOSCC and 129 control cats. Clumping clay cat litter and flea collar use were significant risk factors for FOSCC on multiple logistic regression with odds ratios of 1.66 (95% CI 1.20-2.30) and 4.48 (95% CI 1.46-13.75) respectively. Crystalline silica is a carcinogen that may be present in all clay cat litters and tetrachlorvinphos is a carcinogen that is present in the most commonly used flea collars in our study. We recommend further investigation into the association between FOSCC and clay-based litter and/or flea collars containing tetrachlorvinphos.

Factors that influenced students to matriculate at a northeastern dental school: A comparative study.

PURPOSE/OBJECTIVES: There is a robust body of research on which factors dental schools consider when selecting students for acceptance, but there is considerably less research regarding what factors dental applicants consider when selecting a particular program. The aim of this investigation was to better understand which factors most influenced students to matriculate at a particular dental school and how the value of these factors has changed over time. METHODS: To answer this research question, an online survey was utilized to determine why students chose to attend Columbia University College of Dental Medicine (CUCDM). This survey was administered to students in the Class of 2023 and was compared to the responses of an identical survey that was administered to the Class of 2013. The response rate for the classes of 2013 and 2023 were 70.0% and 42.2%, respectively. Results from the Classes of 2013 and 2023 were analyzed using independent sample T-tests. RESULTS: The Class of 2013 ranked academic reputation, location, and admissions into specialty programs as the three most important factors in their selection of a dental school. The Class of 2023 ranked tuition cost, perceived patient pool, and financial aid as their three most important factors. CONCLUSION(S): For dental schools to continue to successfully attract and enroll students, they must understand what motivates a student to matriculate in a specific dental program. One way to accomplish this is through the use of a survey.

Population pharmacokinetics identifies rapid gastrointestinal absorption and plasma clearance of oral chlorambucil administered to cats with indolent lymphoproliferative malignancies.

OBJECTIVE: To establish the pharmacokinetics of a single 2-mg oral dose of chlorambucil in cats with indolent lymphoproliferative malignancies. ANIMALS: 24 client-owned cats. PROCEDURES: Cats were assigned to 1 of 4 groups, with each group having a total of 3 sample collection time points over 12 hours after receiving a single 2-mg oral dose of chlorambucil. Each time point combined to generate 6 full patient plasma chlorambucil concentration-time curves from the 24 cats. Chlorambucil treatment was continued every other day and a single, variably timed sample collection was obtained on day 14. Population parameter estimates were obtained by nonlinear mixed-effects modeling. Covariates investigated included age, sex, baseline serum cobalamin, study location, weight, and body condition score. RESULTS: Chlorambucil administered orally to cats was found to have a peak plasma concentration of approximately 170 ng/mL (SE, 31.1 ng/mL), percent coefficient of variation (%CV) of 18.4% within 15 minutes, and a terminal half-life of 1.8 hours (SE, 0.21 hour; %CV, 12.4). At the 4-hour mark, a smaller secondary peak in plasma chlorambucil was found. Day 14 samples were similar to those of the initial dose. No covariates showed a significant effect in the population model. CLINICAL RELEVANCE: In these cats, chlorambucil at a 2-mg dose administered every other day undergoes rapid gastrointestinal absorption and plasma clearance with no drug accumulation between doses. These data are critical to inform future work investigating the association of chlorambucil drug exposure with adverse events and outcome of cats with lymphoproliferative diseases.

Retrospective immunohistochemical investigation of suspected non-visceral leiomyosarcoma in dogs.

Visceral leiomyosarcoma is well described in dogs, but information about non-visceral locations and prevalence is lacking. The diagnosis of leiomyosarcoma is challenging without a gold standard, and often includes the use of immunohistochemical (IHC) stains. We used defined histopathologic patterns, histochemical staining, and IHC staining for smooth muscle actin (SMA), desmin, and laminin to characterize suspected non-visceral leiomyosarcoma in dogs at a single academic institution. In a retrospective search, we identified 24 dogs with a definitive or suspected histologic diagnosis of leiomyosarcoma in a non-visceral location. Histopathology results and clinical details were obtained. Biopsy sections were reviewed by a single pathologist using standardized histologic criteria, including light microscopic appearance, immunohistochemistry (more than two-thirds of neoplastic cells labeled with SMA and desmin or laminin), and histochemical staining (minimal-to-mild matrix deposition by Masson trichrome). Of the 24 cases of possible non-visceral leiomyosarcomas, 4 were consistent with a definitive diagnosis of non-visceral leiomyosarcoma (3) or leiomyoma (1) based on the established criteria. Only the leiomyoma had more than two-thirds of neoplastic cells label with all 3 markers; all 3 leiomyosarcomas had more than two-thirds of neoplastic cells label with SMA and laminin. Our data highlight the uncommon nature of non-visceral leiomyosarcoma and the importance of IHC for their diagnosis. A definitive diagnosis could not be made based on SMA alone, and desmin was not useful in this cohort. Further studies are needed to clarify the histopathologic, IHC, and clinical features of canine non-visceral SMA-positive mesenchymal tumors.

Clinical outcome and Ki67 evaluation in dogs with nodal small cell B-cell lymphoma diagnosed by flow cytometry.

BACKGROUND: Nodal small cell B-cell lymphoma subtypes in dogs cannot be distinguished by flow cytometry and information regarding treatment, prognosis, and outcome are limited. HYPOTHESIS/OBJECTIVES: Objectives were to describe outcome in dogs with nodal small cell B-cell lymphoma diagnosed by flow cytometry and correlate clinical and laboratory data with survival. We hypothesized that B-cell Ki67 expression measured by flow cytometry is associated with shorter progression free survival (PFS) and overall survival (OS). ANIMALS: Forty-nine dogs with nodal small cell B-cell lymphoma, defined by >80% CD21+ B-cells by flow cytometry and small-sized B-cells by forward scatter. METHODS: Retrospective study reviewing treatment and outcome data extracted from medical records. Percentage of Ki67-expressing B-cells was measured by flow cytometry. Clinical, laboratory, and flow cytometry data were assessed for association with outcome. RESULTS: Median percentage of B-cell Ki67 was 41% (range, 3%-97%). Median PFS was 119 days and median OS was 222 days (n = 49). Among cases treated with CHOP-based chemotherapy (n = 32), median PFS was 70 days, median OS was 267 days, and 50% of cases achieved complete response. Low percentage of B-cell Ki67 (≤11%) was associated with prolonged OS by univariable analysis. Greater age, substage B, high B-cell CD25 expression and low B-cell CD21 and class II major histocompatibility complex expression by flow cytometry were independently associated with shorter OS. CONCLUSIONS AND CLINICAL IMPORTANCE: Most nodal small cell B-cell lymphoma cases had aggressive disease. Low Ki67 expression can help identify cases with better prognosis. Age, substage, and flow cytometry variables are useful prognostic factors.

Evaluation of the use of a novel bioabsorbable polymer drug-eluting microsphere for transarterial embolization of hepatocellular neoplasia in dogs.

In dogs with non-resectable hepatic neoplasia, treatment options are limited. The objectives of this study were to describe the use of a novel drug-eluting embolic microsphere containing paclitaxel for use during transarterial chemoembolization (TACE), to compare results of liver-specific owner questionnaires and tumor volume pre- and post-TACE, and to measure systemic paclitaxel concentration post-TACE. Client-owned dogs with non-resectable hepatic neoplasia were prospectively enrolled. All owners completed questionnaires validated for the assessment of subjective outcomes in dogs with cancer before the TACE procedure and approximately 4 weeks after the TACE procedure. A CT scan was performed before TACE and 1 month after TACE; results were compared. Blood samples were obtained at specified time points post-TACE to determine systemic paclitaxel concentrations. Seven dogs (median weight: 8.9 kg; range, 4.3-31 kg) were enrolled. TACE was successfully performed in all dogs, and no intra-procedural complications were encountered. Questionnaire scores improved significantly post-TACE. Among the 6 dogs for which full data were available, median pre-TACE tumor volume was 390 cc (range 152-1,484; interquartile range 231-1,139) and median post-TACE tumor volume was 203 cc (range 98-889; interquartile range 151-369), which was significantly (P = .028) lower. All 6 dogs had a reduction in volume at the post-TACE measurement. Mean percent change in tumor volume was -45.6% (95%CI -58.6 to -32.6%). The mean plasma paclitaxel concentration in canine blood peaked at 4 days post-TACE procedure and was 25.7 ng/mL (range = 3.09-110 ng/mL) Median survival time was 629 days (95%CI 18 to upper limit not reached). The use of a novel paclitaxel-eluting microsphere in this cohort of dogs successfully decreased tumor volume significantly after TACE and improved clinical signs. Future investigation into the use of TACE and other similar therapies is warranted due to the promising outcomes noted in this cohort.

Inhaled recombinant human IL-15 in dogs with naturally occurring pulmonary metastases from osteosarcoma or melanoma: a phase 1 study of clinical activity and correlates of response.

PURPOSE: Although recombinant human interleukin-15 (rhIL-15) has generated much excitement as an immunotherapeutic agent for cancer, activity in human clinical trials has been modest to date, in part due to the risks of toxicity with significant dose escalation. Since pulmonary metastases are a major site of distant failure in human and dog cancers, we sought to investigate inhaled rhIL-15 in dogs with naturally occurring lung metastases from osteosarcoma (OSA) or melanoma. We hypothesized a favorable benefit/risk profile given the concentrated delivery to the lungs with decreased systemic exposure. EXPERIMENTAL DESIGN: We performed a phase I trial of inhaled rhIL-15 in dogs with gross pulmonary metastases using a traditional 3+3 cohort design. A starting dose of 10 µg twice daily × 14 days was used based on human, non-human primate, and murine studies. Safety, dose-limiting toxicities (DLT), and maximum tolerated dose (MTD) were the primary objectives, while response rates, progression-free and overall survival (OS), and pharmacokinetic and immune correlative analyses were secondary. RESULTS: From October 2018 to December 2020, we enrolled 21 dogs with 18 dogs reaching the 28-day response assessment to be evaluable. At dose level 5 (70 µg), we observed two DLTs, thereby establishing 50 µg twice daily × 14 days as the MTD and recommended phase 2 dose. Among 18 evaluable dogs, we observed one complete response >1 year, one partial response with resolution of multiple target lesions, and five stable disease for an overall clinical benefit rate of 39%. Plasma rhIL-15 quantitation revealed detectable and sustained rhIL-15 concentrations between 1-hour and 6 hour postnebulization. Decreased pretreatment lymphocyte counts were significantly associated with clinical benefit. Cytotoxicity assays of banked peripheral blood mononuclear cells revealed significant increases in peak cytotoxicity against canine melanoma and OSA targets that correlated with OS. CONCLUSIONS: In this first-in-dog clinical trial of inhaled rhIL-15 in dogs with advanced metastatic disease, we observed promising clinical activity when administered as a monotherapy for only 14 days. These data have significant clinical and biological implications for both dogs and humans with refractory lung metastases and support exploration of combinatorial therapies using inhaled rhIL-15.

Retrospective Evaluation of Acute Kidney Injury After Zoledronic Acid Administration to Dogs With Malignant Osteolysis.

Zoledronic acid (ZOL) is an intravenous bisphosphonate indicated for the use of hypercalcemia of malignancy and management of bony metastases. Its therapeutic effect lies in the targeting of malignant osteoclasts; however, administration can be associated with renal toxicity. The objective of this retrospective study was to evaluate the frequency and severity of acute kidney injury (AKI) following ZOL administration in a cohort of cancer-bearing dogs. A pharmacy search was conducted to identify dogs that received a dose of ZOL between June 2016 and July 2019. Inclusion criteria included baseline and post-treatment chemistry panels. Medical records were reviewed to obtain clinical data including signalment, dose, dosage, number of treatments administered, and changes in renal function. Forty-four dogs met the inclusion criteria. Median number of doses administered was three [interquartile range (IQR), 2-5]. The median highest creatinine value occurred after a median of one dose (IQR, 1-2 doses) compared with the median highest value of blood urea nitrogen, phosphorus, and potassium, which occurred after a median of two doses (IQR, 1-3). Six (13.6%) dogs developed an AKI, and one dog (2.3%) had progression of an existing azotemia after treatment with ZOL was initiated. Two dogs (4.5%) had ZOL treatment discontinued secondary to development of azotemia. Use of concurrent administration of non-steroidal anti-inflammatory drugs or anesthesia did not significantly increase the risk of AKI in this cohort of dogs. Acute kidney injury is observed infrequently in cancer-bearing dogs treated with ZOL and is generally mild to moderate in severity; discontinuation of ZOL due to AKI is uncommon.

Procedural description and prospective evaluation of short-term outcome for the use of prostatic artery embolization in dogs with carcinoma of the prostate.

OBJECTIVE: To describe the procedure of prostatic artery embolization (PAE) in dogs with prostatic carcinoma and to evaluate the short-term outcome for treated dogs. ANIMALS: 20 client-owned dogs with prostatic carcinomas between May 2014 and July 2017. PROCEDURES: In this prospective cohort study, dogs with carcinoma of the prostate underwent PAE with fluoroscopic guidance. Before and after PAE, dogs underwent CT and ultrasonographic examinations of the prostate, and each owner completed a questionnaire about the dog's clinical signs. Results for before versus after PAE were compared. RESULTS: Prostatic artery embolization was successfully performed in all 20 dogs. Tenesmus, stranguria, and lethargy were significantly less common 30 days after PAE (n = 2, 1, and 0 dogs, respectively), compared with before PAE (9, 10, and 6 dogs, respectively). Median prostatic volume was significantly less 30 days after PAE (14.8 cm3; range, 0.4 to 48.1 cm3; interquartile [25th to 75th percentile] range, 6.7 to 19.5 cm3), compared with before PAE (21.7 cm3; range, 2.9 to 77.7 cm3; interquartile range, 11.0 to 35.1 cm3). All dogs had a reduction in prostatic volume after PAE, with a median prostatic volume loss of 39.4% (95% CI, 20.3% to 59.3%). CONCLUSIONS AND CLINICAL RELEVANCE: Prostatic artery embolization was associated with decreased prostate volume and improved clinical signs in this cohort. The short-term response to PAE appears promising, and evaluation of the long-term impact on survival time is needed.

Use of percutaneous microwave ablation in the treatment of retroperitoneal neoplasia in three dogs.

CASE DESCRIPTION: 3 dogs with retroperitoneal masses (2 renal and 1 located near the diaphragm) were treated by percutaneous microwave ablation (MWA). CLINICAL FINDINGS: Dogs between 11 and 13 years of age weighing between 13.7 and 43.8 kg had either a renal mass (n = 2) or a mass located in the caudodorsal aspect of the retroperitoneal space near the right side of the diaphragm (1). Cytology revealed that one of the renal masses and the mass located near the diaphragm were malignant neoplasias. Findings on cytologic evaluation of a sample of the other renal mass was nondiagnostic. Maximum mass diameters ranged between 1.4 and 2.5 cm. TREATMENT AND OUTCOME: All dogs were treated by percutaneous MWA. Probes were directed into tumors by use of ultrasound and CT guidance, and microwave energy was applied to each mass. Findings on imaging of each mass following MWA was consistent with successful treatment. No intraprocedural or major postprocedural complications occurred, and all dogs were discharged from the hospital within 3 days of treatment. Two dogs died at 3 and 21 months after MWA with no known local recurrence; 1 dog was still alive 64 months after treatment. CLINICAL RELEVANCE: Although the indications for MWA in the treatment of neoplasia in companion animals are limited, the outcomes of dogs in the present report provided preliminary evidence that percutaneous MWA can be safely used to effectively treat retroperitoneal neoplasia. This procedure was successfully performed with image guidance in all 3 dogs.

Evaluation of accuracy for 18 F-FDG positron emission tomography and computed tomography for detection of lymph node metastasis in canine oral malignant melanoma.

Tumour stage has been demonstrated to have prognostic significance in canine oral malignant melanoma (OMM). Various evaluation techniques of positron emission tomography/computed tomography (PET/CT) have been reported for staging of head-and-neck tumours in people, but canine-specific data are limited, and reports for CT accuracy have been variable. In this prospective study, the head/neck of client-owned dogs with cytologically or histologically diagnosed OMM were imaged with 18 Fluorine-fluorodeoxyglucose (18 F-FDG) PET/ CT. Bilateral mandibular lymphadenectomy was performed for histopathologic assessment. Two evaluation techniques for CT and PET were applied by four independent observers. CT evaluation utilized both a standardized grading scheme and a subjective clinical interpretation. PET evaluation was first performed solely on 18 F-FDG-uptake in lymph nodes compared to background on a truncated scan excluding the oral cavity. Subsequently, the entire head/neck scan and standardized uptake value (SUV) measurements were available. Receiver operating characteristic analysis was performed with histopathology as gold standard. Twelve dogs completed the study and metastatic OMM was identified in six mandibular lymph nodes from five dogs. Of the CT-interpretation techniques, use of clinical grading performed best (sensitivity = 83% and specificity = 94%). Both PET techniques resulted in 100% sensitivity, but primary tumour site evaluation and use of SUV increased specificity from 78% to 94%. The SUVmax cut-point, 3.3, led to 100% sensitivity and 83% specificity. In this population of dogs, PET appeared to be highly sensitive but at risk of being less specific without use of appropriate parameters and thresholds.

Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events (VCOG-CTCAE v2) following investigational therapy in dogs and cats.

The updated VCOG-CTCAE v2 guidelines contain several important updates and additions since the last update (v1.1) was released in 2011 and published within Veterinary and Comparative Oncology in 2016. As the Veterinary Cooperative Oncology Group (VCOG) is no longer an active entity, the original authors and contributors to the VCOG-CTCAE v1.0 and v1.1 were consulted for input, and additional co-authors sought for expansion and refinement of the adverse event (AE) categories. VCOG-CTCAE v2 includes expanded neurology, cardiac and immunologic AE sections, and the addition of procedural-specific AEs. It is our intent that, through inclusion of additional authors from ACVIM subspecialties and the American College of Veterinary Surgery, that we can more comprehensively capture AEs that are observed during clinical studies conducted across a variety of disease states, clinical scenarios, and body systems. It is also our intent that these updated veterinary CTCAE guidelines will offer improved application and ease of use within veterinary practice in general, as well as within clinical trials that assess new therapeutic strategies for animals with a variety of diseases. Throughout the revision process, we strived to ensure the grading structure for each AE category was reflective of the decision-making process applied to determination of dose-limiting events. As phase I trial decisions are based on these criteria and ultimately determine the maximally tolerated dose, there is impact on standard dosing recommendations for any new drug registration or application. This document should be updated regularly to reflect ongoing application to clinical studies carried out in veterinary patients.

Adjuvant Sirolimus Does Not Improve Outcome in Pet Dogs Receiving Standard-of-Care Therapy for Appendicular Osteosarcoma: A Prospective, Randomized Trial of 324 Dogs.

PURPOSE: The mTOR pathway has been identified as a key nutrient signaling hub that participates in metastatic progression of high-grade osteosarcoma. Inhibition of mTOR signaling is biologically achievable with sirolimus, and might slow the outgrowth of distant metastases. In this study, pet dogs with appendicular osteosarcoma were leveraged as high-value biologic models for pediatric osteosarcoma, to assess mTOR inhibition as a therapeutic strategy for attenuating metastatic disease progression. PATIENTS AND METHODS: A total of 324 pet dogs diagnosed with treatment-naïve appendicular osteosarcoma were randomized into a two-arm, multicenter, parallel superiority trial whereby dogs received amputation of the affected limb, followed by adjuvant carboplatin chemotherapy ± oral sirolimus therapy. The primary outcome measure was disease-free interval (DFI), as assessed by serial physical and radiologic detection of emergent macroscopic metastases; secondary outcomes included overall 1- and 2-year survival rates, and sirolimus pharmacokinetic variables and their correlative relationship to adverse events and clinical outcomes. RESULTS: There was no significant difference in the median DFI or overall survival between the two arms of this trial; the median DFI and survival for standard-of-care (SOC; defined as amputation and carboplatin therapy) dogs was 180 days [95% confidence interval (CI), 144-237] and 282 days (95% CI, 224-383) and for SOC + sirolimus dogs, it was 204 days (95% CI, 157-217) and 280 days (95% CI, 252-332), respectively. CONCLUSIONS: In a population of pet dogs nongenomically segmented for predicted mTOR inhibition response, sequentially administered adjuvant sirolimus, although well tolerated when added to a backbone of therapy, did not extend DFI or survival in dogs with appendicular osteosarcoma.