Laura Blackwood

European consensus document on mast cell tumours in dogs and cats

In preparing this document the Authors aimed to pool current information on canine and feline mast cell disease. The information was gathered from international studies and a emphasis was placed on material and opinion with a strong evidence base. We intend it to form the basis of our understanding in this disease at the current time and we anticipate that it will be particularly useful for the general practitioner. It should be emphasized that the authors are presenting this work from a European perspective.

Owners ‘perception of their cats’ quality of life during COP chemotherapy for lymphoma

Questionnaires regarding the perceptions of chemotherapy and its impact on the quality of life (QoL) of their cat were received from owners of 31 cats treated for lymphoma between 2002 and 2006 with COP (cyclophosphamide, vincristine, prednisolone) chemotherapy. The QoL scores prior to the onset of cancer (mean 9.5, range 6–10) were significantly higher than the ratings given after the onset of cancer but before commencement of chemotherapy (mean 3.9, range 1–9.4). The QoL scores during chemotherapy (mean 6.3, range 1–10) were also significantly lower than prior to the onset of cancer, but significantly higher during treatment than prior to starting treatment. Adverse effects were experienced by 27 (87%) cats during the course of chemotherapy. Twenty-five (83%) of clients were happy they treated their cat and 27 owners (87%) would treat another cat. The results suggest that COP chemotherapy is perceived by owners to be tolerated by cats.

Clinical pathological and epidemiological assessment of morphologically and immunologically confirmed canine leukaemia

Traditionally, classification of leukaemia in dogs has relied on morphological examination and cytochemical staining patterns, but aberrant cellular morphology and stain uptake often curtails accurate categorization, and historical data based on this classification may be unreliable. Immunophenotyping is now the gold standard for classification of leukaemias. The purpose of this prospective study was to assess the clinical pathological and epidemiological features of a population of dogs with morphologically and immunologically confirmed leukaemia and to compare them within categories: acute and chronic lymphoid leukaemia (ALL and CLL), and acute and chronic myeloid leukaemia (AML and CML). There were 64 cases of morphologically and immunologically confirmed leukaemia: 25 cases of ALL, 17 cases of CLL and 22 cases of AML. Prevalence of B and T immunophenotypes in ALL and CLL was not statistically different. Dogs with AML were significantly younger than those with ALL at presentation (P = 0.04). Golden Retriever dogs in the study population were overrepresented in comparison with a control population of dogs (6/25 ALL cases, 8/64 leukaemia cases). No sex was overrepresented. Dogs with ALL had significantly more severe neutropenia (P = 0.001) and thrombocytopenia (P = 0.002) than those with CLL and had significantly more cytopenias. The severity and numbers of cytopenias seen in ALL and AML were not significantly different. Twenty-one of the leukaemia cases showed one cytopenia, fourteen had two cytopenias and twenty-one cases had pancytopenia. Anaemia was the most common cytopenia seen in isolation (17/21). No dogs had neutropenia without anaemia and/or thrombocytopenia. Total white blood cell counts were not different between the groups. The atypical cell counts within the peripheral blood were significantly higher in ALL than AML; both in isolation and as a percentage of the total white blood cell count (P = 0.03). This study strengthens the hypothesis that acute leukaemias give rise to more profound cytopenias, affecting more cell lines, than chronic leukaemias.

RAS, FLT3, and C-KIT mutations in immunophenotyped canine leukemias

OBJECTIVE To determine the frequency of FLT3, C-KIT, and RAS mutations in canine leukemia patients. MATERIALS AND METHODS Ethylenediamine tetra-acetic acid blood samples were recruited from dogs with suspected leukemia, categorized by quantitative and cytological evaluation and immunophenotyping. Flow cytometry was carried out using antibodies against CD3; CD3e; CD4; CD5; CD8; CD11a, b, c, and d; CD14; CD21; CD34; CD45 and 45RA; CD79a; CD90 (THY-1); major histocompatibility complex II; myeloperoxidase; MAC387; and neutrophil-specific antibody. Genomic DNA was extracted from whole blood and analyzed for mutations in N, H, and K-RAS, FLT3, and C-KIT genes by polymerase chain reaction and sequencing. RESULTS Fifty-seven (77.0%) of 74 samples submitted from dogs with suspected leukemia had cytologically and immunophenotypically confirmed leukemia. There were 36 (63.2%) acute leukemias, 16 (28.1%) chronic, 3 (5.3%) prolymphocytic, 1 natural killer cell, and 1 chronic leukemia undergoing blast transformation. N-RAS mis-sense mutations were identified in 14 (25%) dogs with acute myeloid (AML) or lymphoid (ALL) leukemia, and also in one dog in the leukemic phase of lymphoma. Mutations in K-RAS were found in two dogs with AML. There were no H-RAS mutations. FLT3 internal tandem duplications were identified in three dogs with ALL, and a mis-sense mutation was found in one dog with ALL. C-KIT mutations were identified in three dogs with AML. Sixty-one percent of dogs with acute leukemia harbored mutations in N/K-RAS, FLT3, or C-KIT. CONCLUSION RAS, FLT3, and C-KIT mutations, analogous to those found in human leukemia, occur commonly in acute canine leukemia.

Determination of serum fPLI concentrations in cats with diabetes mellitus

Diabetes mellitus (DM) is one of the most common feline endocrinopathies. Pancreatitis is a reported cause for poor control of DM in cats; however, its prevalence in diabetic cats is unknown. Measurement of serum feline pancreatic lipase immunoreactivity (fPLI) has been proposed as a sensitive and specific test for the detection of pancreatitis in cats. The aim of this study was to assess fPLI concentrations in diabetic cats and compare these with non-diabetic cats of similar age. Samples from 29 cats with DM and 23 non-diabetic cats were analysed. Serum fPLI concentrations were significantly higher in samples from diabetic cats (P<0.01). A weak association was found between serum fructosamine and fPLI concentrations (R2=0.355, P=0.015), but there was no association between fPLI concentrations and the degree of diabetic control. There were no significant differences in reported clinical signs between cats with or without DM regardless of serum fPLI concentration. This is the first study to demonstrate elevated serum fPLI concentrations in cats with DM, suggesting that pancreatitis could be a significant comorbidity in these cats.

Oral malignant melanoma – the effect of coarse fractionation radiotherapy alone or with adjuvant carboplatin therapy

Abstract A retrospective study was undertaken of dogs presented to the Animal Health Trust for treatment of oral malignant melanoma, without radiographic evidence of pulmonary metastases. Group 1 (n = 13) received radiotherapy of the primary and any lymph node metastases (4 weekly fractions of 9 Gy); and group 2 (n = 15) were treated the same but additionally received between two and six doses carboplatin at 300 mg m(-2) every 3 weeks. Median survival times for the two groups were 307 and 286 days, respectively (P > 0.05). In addition, carboplatin therapy did not significantly reduce the proportion of dogs dying due to metastases (three from group 1 and four from group 2). We found no evidence of a beneficial effect of carboplatin therapy over radiotherapy alone.

Canine tonsillar squamous cell carcinoma -- a multi-centre retrospective review of 44 clinical cases.

OBJECTIVES To review the presenting clinical signs, treatment and survival of dogs with tonsillar squamous cell carcinoma and, if possible, to identify useful prognostic indicators. METHODS Medical records of 44 dogs were reviewed retrospectively. Clinical signs, clinical stage, time of diagnosis, treatment and outcome were recorded. Data were analysed using the Kaplan-Meier, log-rank, Students t test, Kruskal-Wallis test and Chi-square/Fisher Exact test as appropriate. RESULTS The most frequent clinical signs were cough (12 dogs, 27%), enlarged lymph nodes (11 dogs, 25%) and dysphagia (11 dogs, 25%). Anorexia and lethargy were less common but were significantly associated with a poor outcome. No matter what treatment modalities were used, survival times were short and median survival time for all the dogs in the study was 179 days. However, there were a small number of long-term survivors. CLINICAL SIGNIFICANCE Dogs with tonsillar squamous cell carcinoma that suffered anorexia and lethargy had shorter survival times than patients without these clinical signs. Although surgery, chemotherapy and radiotherapy seem to increase the median survival time of dogs diagnosed with tonsillar squamous cell carcinoma, there is no highly effective treatment for canine tonsillar squamous cell carcinoma.

Hypocobalaminaemia is uncommon in cats in the United Kingdom.

Recent work has highlighted the importance of cobalamin deficiency in cats with a range of alimentary tract diseases. The primary aim of our study was to determine the incidence of subnormal cobalamin concentrations in sick cats with and without alimentary system disorders. Firstly, serum cobalamin concentrations were measured in a population of cats, with and without gastrointestinal (GI) disease, evaluated at a referral hospital. In the second part of the study, the incidence of cobalamin deficiency was assessed in samples submitted to a commercial laboratory specifically for cobalamin measurement. For both studies, a validated radioimmunoassay was used to measure serum cobalamin concentrations (reference range: >150 pg/ml). In the first part of the study, 132 cats were included and none of these cats had subnormal cobalamin concentrations (median=1172; range: 278 to >2000). There were no differences in cobalamin concentrations between cats with alimentary system disorders, and those with diseases of other organs. In the second part, 682 samples were submitted for cobalamin assay over a period of 3 years, and only one cat had a result below the reference range (median=794; range: 147 to >2000). Cobalamin deficiency was rare in the population tested and this may suggest that the incidence of this biochemical abnormality is less common than reported in the USA.

Thymidine kinase assay in canine lymphoma

The aim of the study was to evaluate if thymidine kinase (TK) correlated with duration of first remission (DFR) or survival in dogs with lymphoma and if initial TK levels correlated with stage and substage; and also to assess if TK level at diagnosis correlated with immunophenotype. TK was assayed in 73 dogs with treatment naïve lymphoma, then again after treatment; 47% had an initial TK above the reference interval. Dogs with B-cell lymphoma had higher initial TK activities than dogs with T-cell lymphoma. TK levels were not higher in dogs with higher stage disease and TK activity prior to treatment was not associated with DFR or survival. Where TK was elevated at diagnosis, it fell into the reference range during remission. TK was normal in 53% dogs at diagnosis, which is higher than previously reported. Further studies are warranted to assess the utility of TK in dogs with lymphoma.

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.