Lymphadenectomy improves outcome in dogs with resected Kiupel high-grade cutaneous mast cell tumours and overtly metastatic regional lymph nodes.

INTRODUCTION: Historically, the prognosis for dogs with stage II Kiupel high-grade cutaneous mast cell tumours has been considered poor. OBJECTIVES: The aim of this study was to explore the impact of lymphadenectomy on outcome in dogs with Kiupel high-grade cutaneous mast cell tumours and overt regional lymph node metastasis. MATERIAL AND METHODS: Data from dogs with completely staged Kiupel high-grade cutaneous mast cell tumours with overt and/or certain regional lymph node metastasis undergoing excision of the primary tumours and adjuvant medical treatment were extracted. Dogs with a cytological diagnosis of regional lymph node metastasis that did not undergo lymphadenectomy were compared with dogs that underwent lymphadenectomy and had a histological diagnosis of overt lymph node metastasis. RESULTS: Forty-nine dogs were included, 18 did not undergo lymphadenectomy while 31 underwent lymphadenectomy. Median time to progression was significantly shorter in dogs that did not undergo lymphadenectomy (150 days, 95% confidence interval: 129 to 170) compared to the other dogs (229 days, 95% confidence interval: 191 to 266). Median survival time was also shorter in dogs that did not undergo lymphadenectomy (250 days, 95% confidence interval: 191 to 308) compared to dogs that underwent lymphadenectomy (371 days, 95% confidence interval: 311 to 430). On multivariable analysis, lack of lymphadenectomy was associated with higher risk of overall tumour progression (hazard ratio: 2.05, 95% confidence interval: 1.02 to 4.13), nodal progression (hazard ratio: 3.4, 95% confidence interval: 1.65 to 7.02) and tumour-related death (hazard ratio 3.63, 95% confidence interval: 1.72 to 7.66), whereas tumour size was associated with higher risk of local recurrence (hazard ratio: 3.61, 95% confidence interval: 1.06 to 13). CLINICAL SIGNIFICANCE: Regional lymphadenectomy may improve outcome in dogs with biologically aggressive cutaneous mast cell tumours.

Recombinant human thyrotropin stimulation test in 114 dogs with suspected hypothyroidism: a cross-sectional study.

OBJECTIVE: To evaluate the performance and define cut-offs for the interpretation of a thyroid-stimulating hormone (TSH) stimulation test with a recombinant human TSH dose of 75 µg/dog administered intravenously in dogs with suspected hypothyroidism. MATERIALS AND METHODS: Cross-sectional study. Medical records of dogs presented for suspected hypothyroidism were retrospectively reviewed. Animals were included if a TSH stimulation test with a recombinant human TSH dose of 75 µg/dog was performed and follow-up was available. Dogs with a post-TSH serum total thyroxine (T4) level of ≥2.2 µg/dL were considered euthyroid. Dogs with a post-TSH T4 level of <2.2 µg/dL were classified as hypothyroid or euthyroid based on follow-up, including response to levothyroxine supplementation. A receiver operating characteristic curve analysis was used to define the performance of the test. RESULTS: One hundred and fourteen dogs were included. Forty were classified as hypothyroid and 74 as euthyroid. Post-TSH T4 cut-offs of 1.3 and 1.7 µg/dL showed sensitivities of 92.5 and 100% and specificities of 97.3 and 93.2%, respectively. Post-TSH T4 levels of >1.7 µg/dL had a negative predictive value of 100%. Post-TSH T4 levels of <1.3 µg/dL showed a positive predictive value of 94.9%. Area under the ROC curve for post-TSH T4 was 0.99. CLINICAL SIGNIFICANCE: A TSH stimulation test performed with a recombinant human TSH dose of 75 µg/dog is highly reliable to discriminate between hypothyroid and euthyroid dogs, even in cases of concurrent non-thyroidal illness or administration of medications. A post-stimulation T4 concentration of >1.7 µg/dL is suggestive of normal thyroid function.