Investigation of a screening programme and the possible identification of biomarkers for early disseminated histiocytic sarcoma in Bernese Mountain dogs

The aim of the study was to construct a screening programme for disseminated histiocytic sarcoma (DHS) in Bernese Mountain dogs using diagnostic imaging and blood analysis and evaluate blood borne biomarkers as early disease detection biomarkers. Healthy Bernese Mountain dogs were screened on four occasions in an attempt to detect early disease. Eleven blood borne biomarkers were examined for their worth as early tumour biomarkers. During 2.5 years, five dogs with early DHS were identified; four of these by diagnostic imaging. No dogs developed symptomatic DHS without being detected within 6 months of the screening programme. Only serum ferritin showed potential as a blood borne marker of the disease. Median survival times for the dogs with early DHS were 226 days. Screening programmes every 6 months for Bernese Mountain dogs over 4 years of age including diagnostic imaging and ferritin measurements may identify early DHS.     

A dose‐finding study with a novel water‐soluble formulation of paclitaxel for the treatment of malignant high‐grade solid tumours in dogs

A new formulation of water‐soluble paclitaxel (Paccal® Vet) has been developed for canine cancer patients, without the need for pre‐medication (traditionally required in non‐water‐soluble paclitaxel formulations). The objective of the study was to determine a clinically safe and efficacious dose of Paccal Vet and to estimate progression‐free and overall survival and to evaluate single‐dose pharmacokinetics in tumour‐bearing dogs. A positive risk:benefit ratio was established for Paccal Vet administered at 150 mg m^–2 intravenous (IV) for three or more treatment cycles. Preliminary efficacy was demonstrated by best objective response rate (86%), median time to response (14 days) and median progression‐free survival (131 days). Paccal Vet was associated with expected adverse events (AE) (e.g. myelosuppression), however the majority were transient, clinically silent and manageable. This is the first clinical report of a water‐soluble formulation of paclitaxel suggesting successful administration and being safely used without pre‐medication in dogs.     

Long‐term survival in dogs with localized histiocytic sarcoma treated with CCNU as an adjuvant to local therapy*

Histiocytic sarcoma (HS) is associated with a poor prognosis owing to the presence of metastasis at the time of diagnosis in most dogs. Improved outcome has been reported in several dogs with localized HS following local therapy, however, distant metastasis occurs in 70–91% of dogs suggesting that adjuvant systemic therapy is necessary. The purpose of this retrospective study was to describe clinical characteristics and outcome in dogs with localized HS treated with aggressive local therapy plus adjuvant CCNU chemotherapy. Data from 16 dogs were evaluated. The median disease‐free interval was 243 days. Two dogs had local recurrence and eight dogs developed metastatic disease with a median time to relapse of 201 days in these 10 dogs. The median survival time for all 16 dogs was 568 days. These results support the recommendation for aggressive local therapy combined with adjuvant CCNU chemotherapy in dogs with localized HS.     

Hypercalcemia and parathyroid hormone‐related peptide expression in a dog with thyroid carcinoma and histiocytic sarcoma

A 9.5‐year‐old, male castrated Walker Hound was presented for evaluation of progressive weakness, anorexia, and weight loss. Imaging revealed multiple abdominal and thoracic masses and ascites; fine‐needle aspirates of mesenteric and splenic masses confirmed malignancy, most likely histiocytic sarcoma. Laboratory analyses revealed increased ionized calcium and parathyroid hormone‐related peptide (PTH‐rP) concentrations, and concurrent low–normal parathyroid hormone concentration, consistent with humoral hypercalcemia of malignancy. Necropsy was performed after euthanasia. The dog had disseminated histiocytic sarcoma, including sarcomatosis, as well as bilateral thyroid carcinoma. PTH‐rP immunostaining was positive in the thyroid carcinoma but negative in the histiocytic neoplasm. These results suggest that thyroid carcinoma‐associated hypercalcemia can be caused by tumor secretion of PTH‐rP.     

Liposomal clodronate treatment for tumour macrophage depletion in dogs with soft‐tissue sarcoma

Increased numbers of tumour‐associated macrophages correlate with rapid tumour growth and metastasis in tumours. Thus, macrophage depletion has potential as a novel cancer therapy and positive responses have been reported in rodent tumour models. To investigate the effectiveness of this approach in dogs with cancer, we evaluated the effects of the macrophage‐depleting agent liposomal clodronate (LC) in dogs with soft‐tissue sarcoma (STS). To this end, we conducted a clinical trial of LC therapy in 13 dogs with STS. Repeated LC administration was well tolerated clinically. Preliminary examination of tumour biopsy sets from 5 of the 13 dogs demonstrated that the density of CD11b⁺ macrophages was significantly decreased after LC treatment. Circulating concentrations of interleukin‐8 were also significantly reduced. These preliminary studies are the first to suggest that LC can be used as a systemic macrophage‐depleting agent in dogs to reduce numbers of tumour‐associated macrophages.     

Quality of life assessment in dogs and cats receiving chemotherapy – a review of current methods

This study aimed to review currently reported methods of assessing the effects of chemotherapy on the quality of life (QoL) of canine and feline patients and to explore novel ways to assess QoL in such patients in the light of the experience to date in human pediatric oncology. A qualitative comparative analysis of published papers on the effects of chemotherapy on QoL in dogs and cats were conducted. This was supplemented with a comparison of the parameters and domains used in veterinary QoL‐assessments with those used in the Pediatric Quality of Life Inventory (PedsQL^?) questionnaire designed to assess QoL in toddlers. Each of the identified publications including QoL‐assessment in dogs and cats receiving chemotherapy applied a different method of QoL‐assessment. In addition, the veterinary QoL‐assessments were mainly focused on physical clinical parameters, whereas the emotional (6/11), social (4/11) and role (4/11) domains were less represented. QoL‐assessment of cats and dogs receiving chemotherapy is in its infancy. The most commonly reported method to assess QoL was questionnaire based and mostly included physical and clinical parameters. Standardizing and including a complete range of potentially relevant parameters in future QoL assessments may benefit owner decision making.     

Lymphangiosarcoma in 12 dogs: a case series (1998–2013)

Lymphangiosarcoma (LAS) is an uncommon malignant neoplasia arising from lymphatic endothelium; little information exists regarding therapy. Single institutional retrospective review for canine LAS histopathology diagnoses over a 15‐year period yielded 12 dogs. Ten dogs were presented for a mass and/or swelling at cervical, trunk or limb regions. Prior to diagnosis, 10 dogs received empiric wound therapy. Cytology performed in 10 consisted of mild inflammation. Survival ranged from 60, 168 and 876 days for three dogs with palliation; 90 days with prednisone in one; 182 days with chemotherapy in one; 240, 267, 487, 630 and 941 days for five receiving surgery; and 574 days for one receiving surgery, radiation and chemotherapy. One dog is alive with recurrence at 243 days following surgery and carboplatin chemotherapy. Clinical improvement existed in LAS dogs receiving multimodal therapies. Early tissue biopsies are recommended for progressive oedematous lesions of unknown origin.     

Cancer‐testis antigens in canine histiocytic sarcoma and other malignancies

Cancer‐testis antigens (CTAs) are a category of self proteins aberrantly expressed in diverse malignancies, mostly solid tumours, due to epigenetic de‐repression. Normally expressed only in fetal or gametogenic tissues, CTAs are tantalizing immunotherapy targets, since autoimmunity risks appear minimal. Few prevalent CTAs have been identified in human hematologic cancers, and just two in their veterinary counterparts. We sought to discover new CTAs in canine hematologic cancers such as histiocytic sarcoma (HS) and lymphoma to foster immunotherapy development. To accomplish this, the ligandome binding the dog leukocyte antigen (DLA)‐88*508:01 class I allele overexpressed in an HS line was searched by mass spectrometry to identify possible CTA‐derived peptides, which could serve as CD8+ T‐cell epitopes. Twenty‐two peptides mapped to 5 human CTAs and 12 additional proteins with CTA characteristics. Expression of five promising candidates was then evaluated in tumour and normal tissue by quantitative and end‐point RT‐PCR. The ortholog of an established CTA, IGF2BP3, had unexpectedly high expression in peripheral blood mononuclear cells (PBMCs). Four other testis‐enhanced proteins were also assessed. AKR1E2, SPECC1 and TPX2 were expressed variably in HS and T‐cell lymphoma biopsies, but also at high levels in critical tissues, including kidney, brain and marrow, diminishing their utility. A more tissue‐restricted candidate, NT5C1B, was detected in T‐cell lymphomas, but also at low levels in some normal dog tissues. These results illustrate the feasibility of discovering canine CTAs by a reverse approach, proceeding from identification of MHC class I‐presented peptides to a comparative RNA expression survey of tumours and normal tissues.     

VEGFR‐2 expression in malignant tumours of the canine mammary gland: a prospective survival study

Vascular endothelial growth factor receptor‐2 (VEGFR‐2) is the main receptor activated by vascular endothelial growth factor ‐A (VEGF‐A) to promote tumour angiogenesis. Its clinical prognostic value has not been studied in canine mammary tumours (CMTs). Dogs with mammary cancer were enrolled in a survival study and the immunohistochemical expressions of VEGFR‐2 and VEGF‐A were analysed and associated with clinicopathological features. VEGFR‐2 expression was associated with VEGF immunoreactivity in cancer cells, supporting the presence of an autocrine loop that may be involved in CMTs growth and survival. VEGFR‐2 was also expressed by endothelial cells from tumour vasculature and positively associated with stromal matrix metalloproteinase‐9 (MMP‐9), suggesting the existence of a link between endothelial cells activation and up‐regulation of matrix degrading proteins. Carcinosarcomas exhibited high VEGFR‐2 expression suggesting that it may be one of the activated molecular pathways in this aggressive histological type and that VEGFR‐2 inhibitors may constitute a potential treatment to improve the prognosis of these patients. Both VEGF and VEGFR‐2 immunoreactivities were independent of patients' overall survival (OS) and disease‐free survival (DFS).     

Immune‐mediated hemolytic anemia and severe thrombocytopenia in dogs: 12 cases (2001–2008)

Objective – To identify and characterize the syndrome of immune‐mediated hemolytic anemia (IMHA) with concurrent severe thrombocytopenia (≤15.0 × 10⁹ platelets/L; [15.0 × 10³ platelets/μL]), and to evaluate prognostic factors, clinicopathologic findings, complications, treatment, outcome, and survival of dogs with this hematologic disorder. Design – Retrospective, observational study. Setting – Veterinary teaching hospital. Animals – Twelve client‐owned dogs with IMHA and severe thrombocytopenia (≤15.0 × 10⁹ platelets/L; [15.0 × 10³ platelets/μL]), without evidence of overt disseminated intravascular coagulation. Interventions – The following data were recorded and analyzed from the electronic medical record: signalment, history, concurrent diseases, clinical signs at presentation, clinicopathologic data, diagnostic testing, radiographic findings, treatment modalities, length of hospitalization, complications, and clinical outcome. All dogs were treated with immunosuppressive doses of corticosteroids. Measurements and Main Results – Twelve dogs were identified with the diagnosis of IMHA and severe thrombocytopenia; of these, 9 (75%) survived, 3 (25%) were euthanized, and none died. Dogs that survived were significantly younger than nonsurvivors (P=0.03). There were no specific clinical signs or therapies associated with survival. Conclusions – Dogs in this study had a mortality rate similar to reported rates for dogs with either disease alone. Overall, younger dogs were more likely to survive. No association between different treatment modalities and overall survival was identified.     

Tolerability and pharmacokinetic profile of a novel benzene‐poly‐carboxylic acids complex with cis‐diammineplatinum (II) dichloride in dogs with malignant mammary tumours

The pharmacokinetic profile, tolerability and efficacy of benzene‐poly‐carboxylic acids complex with cis‐diammineplatinum (II) dichloride (BP‐C1) were studied in dogs with mammary cancer. A three‐level response surface pathway designed trial was performed on seven dogs. At each level BP‐C1 was administered subcutaneously daily for 7 days followed by a 7‐day rest period in a dose escalating manner. Adverse events according to VCOG‐CTCAE, performance status and tumour progression were recorded. The pharmacokinetic profile followed a two‐compartment model with rapid absorption, short distribution, and a slow elimination phase. The overall elimination half‐life was 125 h. The maximum tolerated dose of BP‐C1 was estimated to be above 0.46 mg kg^?1. A significant reduction in VCOG‐CTCAE toxicity which correlated negatively with increasing dose was found. The dogs' general performance status remained unchanged. No decrease in total tumour burden was found, although temporary tumour reduction was seen in some target tumours.