J. W. Elliott

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.

Epirubicin as part of a multi-agent chemotherapy protocol for canine lymphoma.

The aim of the study was to report the outcome of treatment of 97 dogs with lymphoma that received a multi-agent chemotherapy protocol containing epirubicin as the primary anthracycline. Seventy-five dogs received a 25-week protocol with no maintenance phase whilst 22 dogs received a maintenance phase. Complete response rate was 96% and time to first relapse (TTR) and overall survival (OS) time for all dogs were 216 and 342 days, respectively. Dogs with T-cell lymphoma and those classified as WHO substage b had significantly poorer OS times and TTR. The protocol was well tolerated with toxicity similar to doxorubicin-containing protocols. Epirubicin as part of a multi-agent protocol is safe and effective in the treatment of canine multicentric lymphoma. There is a high initial response rate and an overall median survival time that is similar to other published doxorubicin-containing protocols.

Gastrointestinal toxicity after vincristine or cyclophosphamide administered with or without maropitant in dogs: a prospective randomised controlled study

OBJECTIVES To assess the prevalence of gastrointestinal toxicity in dogs receiving chemotherapy with vincristine and cyclophosphamide and the efficacy of maropitant citrate (Cerenia™, Zoetis) in reducing these events. METHODS Dogs receiving chemotherapy with cyclophosphamide or vincristine were randomised to either receive maropitant or not in the period immediately after treatment and for 4 days afterwards. Owners completed a diary of adverse events following treatment. RESULTS Adverse events occurred in 40/58 (69%) dogs in the vincristine group. Most of these adverse events were mild and included: lethargy (62%), appetite loss (43%), diarrhoea (34%) and vomiting (24%). Adverse events occurred in 34/42 (81%) dogs treated with cyclophosphamide. Most of these adverse events were mild and included: lethargy (62%), diarrhoea (36%), appetite loss (36%) and vomiting (21%). There was no difference in total clinical score, vomiting, diarrhoea, appetite loss or lethargy score between dogs treated with maropitant and non-treated dogs in either the vincristine or cyclophosphamide groups. CLINICAL SIGNIFICANCE Chemotherapy-related side effects are frequent but usually mild in dogs receiving vincristine or cyclophosphamide. Prophylactic administration of maropitant does not reduce the frequency of adverse events and maropitant should be administered only as required for individual cases.

Zinc toxicity in two dogs associated with the ingestion of identification tags.

RECENTLY, two patients were presented to the Small Animal Teaching Hospital, University of Liverpool, with haemolytic anaemia, icterus and gastrointestinal signs and were subsequently diagnosed with zinc toxicity. In both cases, metallic gastric foreign bodies were removed antemortem. The foreign

Treatment and Outcome of Four Cats with Apocrine Gland Carcinoma of the Anal Sac and Review of the Literature

Anal sac adenocarcinoma is uncommon in cats. We report the outcome of multi-modality therapy in two cats (surgery, definitive radiotherapy and systemic chemotherapy) and surgery alone in two cats. All received surgical excision of the primary tumour followed by radiotherapy and carboplatin chemotherapy in two cases. Both cats that underwent multimodal therapy developed distant metastatic disease and one developed recurrence of the primary tumour. One cat that underwent surgery alone with incomplete margins also developed rapid recurrence. Overall survival times were 89, 161 and 169 days. One cat that had complete surgical excision is still alive without recurrence 425 days postoperatively. Whilst the role of radiation in the local control of this disease is yet to be defined, clearly a more effective systemic therapy is required before such aggressive local treatment can be routinely recommended.

Temozolomide alone or in combination with doxorubicin as a rescue agent in 37 cases of canine multicentric lymphoma

Temozolomide (TMZ) is an alkylating agent previously used in conjunction with doxorubicin (DOX) to treat dogs with relapsed lymphoma. However, there are very limited data for this drug when used as single agent. The aim of this retrospective study was to evaluate the efficacy and toxicity of TMZ in dogs with relapsed multicentric lymphoma that failed multi-agent chemotherapy protocols, and compare the outcome to a group of dogs receiving the same drug in combination with DOX. Twenty-six patients were included in the TMZ group and 11 in the TMZ/DOX group. Responses were evaluated via retrospective review of the medical records. The overall median survival time (MST) for both groups was 40 days (range 1-527 days). For the TMZ group, median time to progression (TTP) was 15 days (range 1-202 days) and MST 40 days (range 1-527 days), with an overall response rate (ORR) of 32% and 46% recorded toxicities. For the TMZ/DOX group, median TTP was 19 days (range 2-87 days) and MST 24 days (range 3-91 days), with an ORR of 60% and 63% recorded toxicities. However, a proportion of haematological toxicoses may have gone undetected due to the absence of associated clinical signs. The difference in MST and TTP between the 2 groups was not statistically significant. Similarly, no negative prognostic factors were identified. Although responses were generally short lived, this study suggests that TMZ may achieve similar efficacy to TMZ/DOX whilst being associated with a lower frequency of recorded toxicities.

External beam radiotherapy for the treatment of feline salivary gland carcinoma: six new cases and a review of the literature

Case series summary Salivary gland carcinoma is uncommon in cats. We report the outcome of radiation therapy in six cases (four salivary gland adenocarcinomas, one tubulopapillary adenocarcinoma, one carcinoma). Five were treated after surgical excision of the primary tumour, but four had gross disease (primary or metastatic) at the time of starting radiotherapy. Exact progression-free interval from the start of radiotherapy in the two cats where this was known was 120 and 144 days, respectively. One cat was signed off at 766 days with no evidence of recurrence. Another cat was in remission at 202 days (when last seen by the referring practice) but subsequently developed recurrence (date uncertain). Survival time was known for three cats (55 days, 258 days and 570 days from initiation of radiotherapy, respectively). In two cases, locoregional progressive disease (PD) was confirmed, and the other presumed as the cause of death. Two cats, known to have developed PD, were alive at the time of writing (at 206 and 549 days, respectively). No cat died as a result of distant metastatic disease. Relevance and novel information There is a paucity of information on the treatment of salivary gland tumours. In humans, as in cats, there is no optimised standard of care for malignant tumours. It is accepted that, for surgical candidates (even with large tumours), surgery and radiotherapy is superior to radiotherapy alone. However, the benefits of postoperative radiotherapy compared with surgery alone are only clear in patients with high-risk tumours (ie, those with large and invasive primary tumours, close or incomplete margins, high histopathological grade, histological evidence of neural or vascular invasion, or positive lymph nodes). This population is analogous to the population reported here, and likely to most cats presented in practice. Thus, radiation therapy may help improve locoregional control and survival in cats.