Outcome with surgical treatment of canine soft tissue sarcoma in the region of the ischiatic tuberosity: A veterinary society of surgical oncology retrospective study.

The aim of this study was to determine the outcome of dogs with soft tissue sarcoma (STS) within the region of the ischiatic tuberosity (ITSTS) treated surgically. This was a multi-institutional retrospective study. Fifty-two dogs met the inclusion criteria, which were: histologically confirmed STS in the region of the IT treated with surgical resection between March 1st, 2009 and March 1st, 2021 with a minimum follow-up time of 6 months. Data collected included patient signalment, preoperative diagnostics, surgical intent/method, surgical complications, histopathology, margins, outcome and cause of death. Statistical analyses were performed to determine significant factors in the treatment and prognosis of ITSTS. Overall survival time (OST) and disease progression were negatively associated with tumour grade, while recurrence was positively associated with grade and incomplete margins. Of the 52 included dogs, there were 24 grade I, 20 grade II and 7 grade III tumours. Forty dogs had reported histopathologic margins of which 26 were reported to be complete and 14 were incomplete. OST and progression-free survival was not reached for tumours graded as I or II and was 255 and 268 days respectively, for grade III. Median time to recurrence was not reached for tumours excised with complete margins and was 398 days for those with incomplete margins. The surgical complication rate was 25%. ITSTS was not found to be a unique clinical entity in dogs as tumour behavior, treatment recommendations, and prognosis were similar to STS in other locations, with overall outcome and prognosis influenced by histologic grade and margins. While surgical complications were common, none resulted in significant morbidity or mortality.

Contrast-enhanced ultrasound for sentinel lymph node mapping in the routine staging of canine mast cell tumours: A feasibility study.

Canine mast cell tumours (MCTs) typically spread to lymph nodes (LNs) before reaching distant sites, and LN assessment is an important part of MCT staging. Sentinel LN (SLN) mapping techniques to identify draining LNs are being developed and could improve the accuracy of MCT staging. The primary objective of this feasibility study was to determine the safety and effectiveness of contrast-enhanced ultrasound (CEUS) to identify SLNs. Secondary objectives were to determine if the SLNs identified by CEUS coincided with the regional LN predicted by the anatomical lymphosomes, if previous MCT excision altered CEUS SLN findings, and if CEUS could identify MCT nodal metastases. Between June 2017 and March 2019, 59 dogs with 62 MCTs were enrolled. No adverse events related to CEUS were reported. CEUS detected at least 1 SLN in 59/62 MCTs (95.2%, 95% CI: 86.5-99.0%). In only 32/59 (54.2%) MCTs, clinicians would have correctly predicted the SLN(s) identified by CEUS. Among the 35 MCTs that had histological examination of the SLN(s), the prevalence of metastasis was 60% (95% CI: 42.1-76.1%). Additional staging procedures did not reveal any metastases in dogs with histologically non-metastatic SLNs. Integration of CEUS SLN mapping into the routine staging of MCTs is promising, but future studies are required to refine this procedure and to investigate if it would translate into a clinical benefit.

Chemotherapy-induced diarrhoea in dogs and its management with smectite: Results of a monocentric open-label randomized clinical trial.

Chemotherapy-induced diarrhoea (CID) is a frequent chemotherapy adverse event in dogs. Yet, there is currently no consensus regarding its management. Smectite is a natural medical clay, widely used in the treatment of acute diarrhoea in humans. The objectives of this study were to assess the efficacy of smectite in the management of CID in dogs, and to collect epidemiological data on CID. For each episode of diarrhoea, dogs were randomized into two management groups: Smectite group, receiving smectite at 0.5 g/kg PO per day divided in two to three doses initiated at the start of CID; control group, without initial medication. In both groups, rescue metronidazole was prescribed if CID progressed or was not improved within 48 hours. Sixty dogs were recruited and received 426 chemotherapy administrations between June 2017 and March 2019. The incidence rate of CID was 110/426 (25.8%, 95% CI: 21.7%-30.2%), and significantly differed between the chemotherapeutic drugs administered (P < .001). Metronidazole was administered in 5/54 events (9.3%, 95% CI: 3.1%-20.3%) in the smectite group and in 40/56 events (71.4%, 95% CI: 57.5%-82.3%) in the control group (P < .001). The time to resolution of diarrhoea was shorter (P < .001) in the smectite group (median: 19.5 hours, interquartile range [IQR]: 13.5-32 hours) compared with the control group (median: 53 hours, IQR: 31.5-113.5 hours). The results of this study support the administration of smectite in the first-line management of CID in dogs.

Evaluation of a 0.75 × 109 /L absolute neutrophil count cut-off for antimicrobial prophylaxis in canine cancer chemotherapy patients.

Absolute neutrophil count (ANC) cut-offs for antimicrobial prophylaxis in veterinary cancer chemotherapy patients are empirical and vary between institutions. Evidence based cut-offs are vital for antimicrobial stewardship, particularly as global antimicrobial resistance rises. The primary objectives of this study were to evaluate the tolerability of a <0.75 × 109 /l ANC cut-off for antimicrobial prophylaxis in dogs after receiving chemotherapy and its impact on antimicrobial prescription. Predicted nadir ANCs (pnANCs) were stratified into six groups (<0.75 × 109 /l [receiving antimicrobial prophylaxis], 0.75-0.99 × 109 /l, 1-1.49 × 109 /l, 1.5-1.99 × 109 /l, 2.0-3.59 × 109 /l and 3.6-12 × 109 /l [reference interval]). The incidences of post-nadir febrile neutropenia (FN) and non-haematological toxicity (NHT) were compared between groups. Five hundred and eighty-six pnANCs were recorded for 181 dogs. There were four episodes of post-nadir FN and 90 episodes of post-nadir NHT. There was no significant difference in incidence of post-nadir FN (P = .063) or post-nadir NHT (P = .084) between pnANC groups. Antimicrobial prophylaxis was prescribed following 8.8% of the chemotherapy administrations; had cut-off values of <1.0 × 109 /l or <1.5 × 109 /l been used it would have been prescribed in 15.3% and 25.8% of cases respectively. An ANC cut-off of <0.75 × 109 /l for antimicrobial prophylaxis appears to be well tolerated and minimizes the prescription of antimicrobials.

A previously undescribed cutaneous paraneoplastic syndrome in a cat with thymoma.

BACKGROUND: Exfoliative dermatitis is a well-recognized cutaneous paraneoplastic syndrome (PNS) associated with thymoma in cats, of which the clinical and histopathological presentation has been well-characterized. OBJECTIVES: To describe a novel clinical skin manifestation associated with thymoma in a cat. ANIMAL: A 14-year-old neutered female domestic short hair cat. METHODS AND MATERIALS: Physical, abdominal ultrasonographic, thoracic radiographic, ultrasonographic and computed tomographic examinations, histopathological assessment of the skin and mediastinal mass. RESULTS: The cat was presented with noninflammatory alopecia, with a dorsal multifocal distribution. Examination of the alopecic areas using a dermascope indicated an apparent lack of follicular ostia. Histopathological assessment of alopecic areas confirmed follicular and epidermal atrophy, trichilemmal keratinization and mild orthokeratotic hyperkeratosis. Diagnostic imaging revealed a mediastinal mass, which was surgically removed. Histopathological and immunohistopathological examination of the mass was consistent with a thymoma, associated with multiloculated cyst formation and multifocal cholesterol granulomas. Following surgery, hair re-growth was noted in the previously alopecic areas. The cat was euthanized 3.5 months later because of recurrent chylothorax suspected to be a postoperative complication. The alopecic lesions had improved markedly. CONCLUSIONS AND CLINICAL IMPORTANCE: Thymoma-associated PNS might not always manifest as an exfoliative dermatitis and should be considered in the differential diagnosis of multifocal noninflammatory alopecia.

Investigation of the utility of lymph node fine-needle aspiration cytology for the staging of malignant solid tumors in dogs.

BACKGROUND: Fine-needle aspiration cytology (FNAC) of lymph nodes (LNs) is routinely used for staging canine malignant solid tumors, but studies evaluating its efficacy are limited. OBJECTIVES: The primary objectives of this study were to evaluate the sensitivity/specificity of FNAC and the significance of nondiagnostic FNAC when staging canine malignant tumors. A secondary objective was to determine the prevalence of multiple nodal metastases. METHODS: Lymph nodes draining malignant solid tumors assessed with FNAC and histopathology were included. The sensitivity/specificity of FNAC was determined for LNs with diagnostic FNAC, using histopathology as the gold standard. The proportion of nondiagnostic FNAC and associated histopathologic prevalence of metastasis were determined. Among the tumors with multiple LNs assessed, the prevalence of multiple nodal metastases was determined. RESULTS: The sensitivity of FNAC (194 LNs) was 67% for sarcomas, 100% for carcinomas, 63% for melanomas, 75% for mast cell tumors, and 100% for other round cell tumors. The specificity varied between 83% and 96%. Nondiagnostic FNAC was reported in 25% of LNs sampled (65/259), most of which were nonenlarged and/or difficult to access, and 20% of which were metastatic on histopathology. When several LNs were assessed (88/189 tumors), the prevalence of multiple nodal metastases was 24%. CONCLUSIONS: Histopathologic LN evaluation cannot be robustly substituted with FNAC when staging selected canine solid tumors. When a diagnostic FNAC is elusive, the histopathologic assessment remains ideal. Finally, staging should not always be limited to the assessment of a single LN.