Comparison of harmonic shears, diode laser, and scissor cutting and suturing for caudal palatoplasty in dogs with brachycephalic obstructive airway syndrome.

Traditionally, staphylectomy has been performed using scissors cutting and suturing. Alternative surgical techniques such as staphylectomy with monopolar electrocoagulation, CO2 or diode laser, bipolar vessel sealing device and harmonic shears have also been described. The purpose of this prospective study was to compare the difference in surgical time, intraoperative haemorrhage and histological damage between staphylectomy performed with harmonic shears (HSS), diode laser (DLS) and traditional scissor 'cutting and suturing' technique with Metzenbaum scissors (SIS). Group HSS included 17 dogs, whereas Group DLS and Group SIS included 10 dogs each. Double masked histological evaluation was performed on the excised specimens. The harmonic shears resulted in the shortest surgical times (HSS 46 s, DLS 300 s, SIS 360 s; P < 0.001). There was a difference in the intraoperative haemorrhage among the three techniques; intraoperative haemorrhage did not occur in HSS and DLS groups. HSS was associated with more frequent damage involving the connective tissue (P = 0.001), muscle (P = 0.038), salivary gland tissue (P < 0.001), but less oedema was observed (P < 0.001). HSS was the fastest of the techniques evaluated for caudal elongated soft palate resection, resulting in less tissue oedema, and no intra-operative haemorrhage. These characteristics might result in reduced postoperative swelling and airway obstruction compared to other techniques.

Canine cutaneous and subcutaneous mast cell tumours: a narrative review.

Cutaneous and subcutaneous mast cell tumours are common neoplasms in the dog. While the majority can be treated with adequate local therapy alone, a subset demonstrates a biologically aggressive behaviour associated with local recurrence or metastasis. This article reviews the diagnosis and tumour staging of canine mast cell tumours alongside treatment options and the evidence supporting their use. In addition, prognostic markers are evaluated to highlight how one can recognise mast cell tumours that may behave in a biologically aggressive manner as well as the challenges of tumours that are large, infiltrative or in locations not amenable to wide surgical excision.

Owners' perception of their dogs' quality of life during and after radiotherapy for cancer.

OBJECTIVES: To determine the owners' perception of dogs' quality of life before, immediately after and 6 weeks after radiotherapy treatments for a variety of neoplasms and assess owner satisfaction over their decision to treat. MATERIALS AND METHODS: Questionnaires were given to owners whose dogs completed a radiotherapy treatment at a referral radiation oncology centre. Questionnaires were given at three time points: before treatment, on the last day of treatment and more than 6 weeks after the treatment was finished. Owners were asked questions regarding their perception of radiotherapy and the quality of life of their pets before, during and after treatment with radiation therapy. Quality of life was scored from 1 (could not be worse) to 10 (could not be better). RESULTS: Seventy-one owners met the inclusion and exclusion criteria. Results showed that 6 weeks or more after treatment, most owners were happy that they had chosen to treat their dogs (92%) and would treat another pet again, if indicated (88%). Across the three time points, median quality of life perception score was 9. CLINICAL SIGNIFICANCE: Radiotherapy was well tolerated by owners and dogs in this study. The great majority of clients were happy to have pursued radiotherapy, would choose to do it again (if indicated) and would recommend it to a friend.

Prognostic significance of histopathology in canine anal sac gland adenocarcinomas: Preliminary results in a retrospective study of 39 cases.

Metastatic rates and survival times of canine anal sac gland adenocarcinomas (ASGACs) vary among studies, making prognostication difficult. Little is known about the prognostic significance of histopathology of ASGACs. This retrospective study investigated associations between histological features, clinical presentation and outcome for 39 ASGACs. Most tumours were incompletely excised (62%) and had moderate to marked peripheral infiltration (74%). The predominant growth pattern was solid, tubules/rosettes/pseudorosettes and papillary in 49%, 46% and 5% of the cases, respectively. Nuclear pleomorphism was either moderate (77%) or mild (23%). Necrosis and lymphovascular invasion were present in 54% and 10% of the cases, respectively. All histological features except mitotic count and necrosis were associated with nodal metastasis at presentation. A statistically significant poorer outcome was identified for tumours with a solid growth pattern, moderate or marked peripheral infiltration, necrosis and lymphovascular invasion. These results need further validation in a larger cohort of dogs.

Comparison of minichromosome maintenance protein 7, Ki67 and mitotic index in the prognosis of intermediate Patnaik grade cutaneous mast cell tumours in dogs.

A previous study found that minichromosome maintenance protein 7 (MCM7) score was associated with prognosis in dogs with cutaneous mast cell tumours (MCTs) independent of histological grade. The primary aim of this study was to validate this score in a different cohort of dogs focusing exclusively on patients with Patnaik intermediate grade MCTs treated with surgery alone and followed for a minimum of 1 year. A secondary aim was to evaluate the prognostic performance of MCM7 in relation to Kiupel histological grade, mitotic index (MI) and Ki67 index in the same cohort of dogs. Ninety dogs were identified, 82 were low Kiupel grade and 8 were high Kiupel grade. Seventy-two dogs were alive after a median follow-up of 1136 days and 18 dogs died of MCT-related causes after a median of 116 days. A MI threshold of 5 was associated with a sensitivity of 0.39 and a specificity of 0.99 in predicting MCT-related death; for Ki67 a threshold of 0.018 was associated with a sensitivity of 0.78 and a specificity of 0.83; and for MCM7 a threshold of 0.18 gave a sensitivity of 0.83 and a specificity of 0.86. Combining MI, Ki67 and MCM7 showed an improved accuracy of predicting death compared with each individual variable. Therefore, performing Ki67 and MCM7 in dogs with GII MCT, low Kiupel grade and low MI might be a consideration.

Assessment of Lymphoid Molecular Clonality in Canine Thymoma.

The aim of this study was to document the molecular clonality of lymphoid cells in canine thymoma using polymerase chain reaction for antigen receptor rearrangement (PARR). Fifteen formalin-fixed and paraffin wax-embedded samples of canine thymoma were analyzed for T- and B-cell receptor clonality. Two of these 15 cases were excluded from the study due to insufficient DNA concentration. Twelve of the 13 remaining samples (92.3%) showed a polyclonal lymphoid component and in one case the lymphoid component was monoclonal (T-cell clonality). PARR could therefore be a useful tool for differentiating canine thymoma from canine mediastinal lymphoma.

Use of Oncept melanoma vaccine in 69 canine oral malignant melanomas in the UK.

OBJECTIVES: Oral malignant melanomas carry a poor-to-guarded prognosis because of their local invasiveness and high metastatic propensity. The Oncept melanoma vaccine is licensed to treat dogs with stage II or III locally-controlled oral malignant melanoma and this retrospective study aimed to assess survival of affected dogs treated with the vaccine in the UK. MATERIAL AND METHODS: Medical records of dogs with histopathologically-confirmed oral malignant melanoma that received the vaccine as part of their treatment were evaluated. Survival analyses for potential prognostic factors were performed. RESULTS: Sixty-nine dogs were included; 56 dogs, staged I to III, and with previous locoregional therapy, had a median survival time of 455 days (95% CI: 324 to 586 days). Based on Kaplan-Meier survival analysis with associated log-rank testing, no significant prognostic factors were identified for this population. Of the 13 patients with macroscopic disease treated with vaccine alone or in combination therapy, eight showed clinical response. Three patients with stage IV oral malignant melanoma survived 171, 178 and 288 days from diagnosis. CLINICAL SIGNIFICANCE: Patients treated with the melanoma vaccine in our study had survival times similar to their counterparts receiving the vaccine in the USA. There were observed responses in patients with macroscopic disease and so the vaccine could be considered as palliative treatment in dogs with stage IV disease.

Canine oral mucosal mast cell tumours.

Mast cell tumours (MCTs) are the most common cutaneous tumours of dogs, however rarely they can arise from the oral mucosa. This subset of MCT is reported to demonstrate a more aggressive clinical course than those tumours on the haired skin and the authors hypothesised that dogs with oral, mucosal MCT would have a high incidence of local lymph node metastasis at presentation and that this would be a negative prognostic factor. An additional hypothesis was that mitotic index (MI) would be prognostic. This retrospective study examines 33 dogs with MCTs arising from the oral mucosa. The results suggest that oral mucosal MCTs in the dog have a high incidence of lymph node metastasis at diagnosis (55%) which results in a poor prognosis. MI and nodal metastasis is highly prognostic. Loco-regional progression is common in these patients and dogs with adequate local control of their tumour had an improved outcome. Despite a more aggressive clinical course, treatment can result in protracted survivals, even when metastasis is present.

Evaluation of Minichromosome Maintenance Protein 7 and c-KIT as Prognostic Markers in Feline Cutaneous Mast Cell Tumours.

Mast cell tumours (MCTs) are a common skin tumour in cats, but there is currently no histological grading system or reliable prognostic marker for this species (unlike the situation for dogs). This study utilized a set of 71 feline cutaneous MCTs with known clinical outcomes to assess the potential of various prognostic markers, including the cellular proliferation marker minichromosome maintenance protein (MCM)-7, mitotic index and various KIT labelling characteristics, including KIT positivity, KIT labelling pattern and KIT immunoreactivity score (IS). Of the factors studied, the mitotic index and the KIT labelling pattern were the only features associated significantly with survival times, while the proliferation marker MCM7 and the KIT IS were not. The study also highlights the variability of KIT labelling characteristics between tumours, which may prevent use of this marker as a diagnostic and prognostic tool.

Histologic grading of canine mast cell tumor: is 2 better than 3?

Mast cell tumor (MCT) is a common canine cutaneous neoplasm with variable biological behavior. A 2-tier histologic grading system was recently proposed by Kiupel et al to reduce interobserver variation and eliminate prognostic uncertainty of the Patnaik system. This study compared the ability of these 2 grading systems to predict survival in a cohort of dogs with MCTs. However, surgical margins were unknown, and the risk of developing new/metastatic MCTs was not studied. Histologic grade was assessed according to both systems for 137 surgically resected cutaneous MCTs. The relationship between grade and survival was evaluated. According to the Patnaik system, 18 MCTs (13.1%) were classified as grade I, 83 (60.6%) as grade II, and 36 (26.3%) as grade III. Grade III was associated with a poorer prognosis (P < .001), but no significant difference between grades I and II was detected. Grading according to the Patnaik system was based on consensus grading among 3 pathologists, and interobserver variability was not considered. All grade I MCTs were low grade in the Kiupel system, and all grade III were high grade. Among grade II, 71 (85.6%) were low grade, and 12 (14.4%) were high grade, with a 1-year survival probability of 94% and 46%, respectively (P < .001). The 2-tier system had a high prognostic value and was able to correctly predict the negative outcomes of some grade II MCTs. Data also confirm that histologic grading cannot predict biological behavior of each MCT and should be supplemented with molecular methods for more accurate prognostication.

Comparison of mitotic index and Ki67 index in the prognostication of canine cutaneous mast cell tumours.

Proliferation markers are commonly used for prognostication of mast cell tumours. The aim of the study is to compare the relative abilities of Ki67 and mitotic index to predict survival in the same cohort of dogs with cutaneous MCTs. Histological grade, mitotic index and Ki67 index were performed in all samples and clinical information was obtained by a follow-up questionnaire. Ninety-five dogs were included in the study with a median follow-up of 1145 days. Survival times varied significantly between categories of histological grade, mitotic index and Ki67 index. Multivariable analyses showed that the risk of dying due to MCT was similar in dogs with increased Ki67 index [hazard ratio, HR: 3.0 (95% CI 1.3-6.8)] or increased mitotic index [HR: 2.7 (95% CI 1.1-6.5)]. In conclusion, both mitotic index and Ki67 index were able to independently differentiate MCTs with worse prognosis. This distinction is particularly meaningful in selecting intermediate grade MCTs that may benefit from more aggressive local or systemic treatment.

Rectal lymphoma in 11 dogs: a retrospective study.

OBJECTIVES: To retrospectively evaluate the clinical behaviour and immunophenotype of lymphoma of the rectum in dogs. METHODS: Eleven dogs diagnosed with lymphoma of the rectum on histopathology were retrospectively reviewed. Immunohistochemistry with CD3 and CD79a antibodies was performed at diagnosis or retrospectively. RESULTS: Treatment protocol varied with six dogs undergoing surgery and adjuvant chemotherapy, two received chemotherapy after only incisional biopsy, one had surgical resection only, one was treated symptomatically and one dog was not treated. Chemotherapy treatment consisted of either a -low-dose COP (cyclophosphamide - prednisolone - vincristine) protocol (four dogs) or a six-week CHOP-based (cyclophosphamide - vincristine - -prednisolone - anthracycline) protocol (four dogs). Dogs that received chemotherapy lived significantly longer than dogs that did not receive chemotherapy (2352 versus 70 days). Median survival time was not reached, and there was an overall mean survival time of 1697 days. Immunohistochemistry was performed in 10 of 11 samples, and was consistent with B-cell -lymphoma in all cases. CLINICAL SIGNIFICANCE: Canine lymphoma of the rectum is associated with a favourable prognosis. Immunohistochemical evaluation of these lesions was consistent with B-cell lymphoma in all cases in which it was examined.

Initial evaluation of canine urinary cystatin C as a marker of renal tubular function.

OBJECTIVES: To evaluate the performance of a particle-enhanced turbidimetric assay for measuring canine urinary cystatin C and to investigate if the urinary cystatin C to creatinine ratio is higher in dogs with renal disease than in non-renal disease dogs. METHODS: Urinary cystatin C was measured by particle-enhanced turbidimetric assay using an avian antihuman cystatin C antibody and the performance of this assay was evaluated. Clinical relevance was tested in 46 dogs that were divided into three groups: healthy dogs (n=14), non-renal disease dogs (n=17) and dogs with renal disease (n=15). RESULTS: The assay was linear (R(2)=0·99) and precise (mean intra- and inter-assay coefficients of variation were 2·3 and 2·9%, respectively). The recovery was 111·5% and the limit of blank was 0·02 mg/L. Urinary cystatin C and urinary cystatin C to creatinine ratio differed significantly (P<0·001) between the three cohorts of dogs. CLINICAL SIGNIFICANCE: Measurement of cystatin C by particle-enhanced turbidimetric assay performed with high precision and linearity. This assay can be processed on automated clinical chemistry analysers making it widely available to commercial laboratories. Urinary cystatin C to creatinine ratio can differentiate dogs with renal disease from dogs without renal disease. These preliminary results suggest that urinary cystatin C to creatinine ratio is a promising marker for evaluating renal tubular function.

Evaluation of minichromosome maintenance protein 7 as a prognostic marker in canine cutaneous mast cell tumours.

Minichromosome maintenance proteins (MCMs) are sensitive markers of cellular proliferation and have been shown to be significant predictors of survival in several human malignancies. MCM7 was evaluated as a prognostic marker in canine cutaneous mast cell tumours (MCTs). MCM7 immunohistochemistry was performed and an index of MCM7-positive cells calculated in dogs with known outcome. The Receiver Operating Characteristics method was used to individuate the best cut-off value of MCM7 score as predictor of survival. Survival analysis and prognostic variables were analysed with statistical methods. Ninety-five dogs were included with 31 dying of MCTs. A value of 0.18 was used as cut-off value of MCM7 score as a binary variable. The median survival time for MCM7 score ≤0.18 was not reached at 3668 days, whereas for MCM7 score >0.18 was 187 days (log-rank test; P < 0.0001). In the multivariable analysis, MCM7 was significantly associated with survival after controlling for age, surgical margins and histological grade (hazard ratio 9.2; P = 0.001).

Radiotherapy in the management of localized mucocutaneous oral lymphoma in dogs: 14 cases.

Oral mucocutaneous lymphoma is rare in dogs. Surgery and chemotherapy do not usually provide effective long-term control. The objective of this study was to retrospectively evaluate survival of dogs with localized oral lymphoma treated with radiation therapy. The medical database of three institutions was searched for dogs with diagnosis of oral lymphoma treated with radiotherapy. Dogs with evidence of systemic disease were excluded. Survival was calculated with the Kaplan-Meier method and prognostic variables analysed with log-rank test. Fourteen dogs were included in the study. Mean survival was 1129 days [95% confidence interval (CI) 711-1546] with median survival of 770 days. The overall response of radiotherapy was 67% (five complete and three partial responses). A survival advantage was seen in dogs with no evidence of lymph node metastasis (P = 0.002) and that achieved a complete response to radiation therapy (P = 0.013). Radiation therapy was a well-tolerated and effective treatment for localized oral lymphoma.