Treatment of canine mast cell tumors with CCNU (lomustine)

The efficacy and toxicity of CCNU (1-[2-chloroethyl]3-cyclohexyl-1-nitrosourea) were evaluated in 23 dogs with measurable mast cell tumors (MCT). Twenty-two dogs had cutaneous MCT and 1 dog had an intranasal MCT Nineteen (83%) dogs had biopsy of their original mass performed and 4 (17%) had aspiration cytology of masses. Of the 19 tumors histologically graded, 1 (5%) neoplasm was classified as grade I, 10 (53%) were grade II, and the remaining 8 (42%) were grade III. Dogs were treated with CCNU at a dosage of 90 mg/m2 body surface area every 3 weeks. Response could be evaluated in 19 dogs. Eight of the 19 dogs (42%) had a measurable response to CCNU. One dog had a durable complete response for 440 days. Seven dogs (37%) had a partial response for a median and mean duration of 77 days and 109 days, respectively (range, 21-254 days). Treatment with CCNU resulted in stable disease in 6 dogs (32%) for a median and mean duration of 78 days and 122 days, respectively (range, 42-347 days). The acute dose-limiting toxicity was neutropenia 7 days after administration of CCNU. The median and mean neutrophil counts 7 days after CCNU were 1,452 cells/microL and 1,683 cells/microL, respectively (n = 17). Other toxicoses were uncommon. CCNU should be considered an active agent in the treatment of MCT in dogs.     

Doxorubicin and cyclophosphamide for the treatment of canine lymphoma: a randomized,placebo‐controlled study*

Median survival times (STs) for doxorubicin‐treated canine lymphoma range from 5.7 to 9 months. Because dogs treated with multi‐agent protocols have longer STs, we sought to evaluate whether adding cyclophosphamide would improve outcome in canine lymphoma patients while maintaining an acceptable level of toxicity. Thirty‐two dogs with stage III–V multicentric lymphoma were treated with doxorubicin every 3 weeks for five total cycles and prednisone at a tapering dose for the first 4 weeks. Dogs were randomized to receive either cyclophosphamide or placebo concurrently. Seventeen dogs received doxorubicin and placebo, while 15 dogs received doxorubicin and cyclophosphamide. Response, toxicity, progression‐free interval (PFI) and ST were evaluated. The combination of doxorubicin and cyclophosphamide was well tolerated, causing no increase in adverse events over doxorubicin alone. Despite a numeric improvement in outcome in cyclophosphamide treated dogs, the addition of cyclophosphamide did not result in statistically improved response rate, PFI or ST.     

Retrospective analysis of outcome and prognostic factors of subcutaneous mast cell tumours in dogs undergoing surgery with or without adjuvant treatment

Subcutaneous mast cell tumours (SC MCTs) can display a different biological behaviour in dogs when compared to their cutaneous counterpart. There is a paucity of information with regards to the outcome of dogs with SC MCTs treated with surgery and/or receiving adjuvant chemotherapy. The aim of this study was to retrospectively review the outcome of dogs with surgically excised SC MCTs undergoing adjuvant treatment or not. A secondary aim was to assess prognostic factors in the same group. Fifty-two cases were included. Recurrence rate was 15% and 63% of evaluated lymph nodes were consistent with early or overt metastasis. Median survival time (range 83–1357 days) and median time to progression (range 14–1357 days) were not reached. Factors predictive of shorter overall survival time included increasing age (HR 1.29, 95% CI 1.06–1.55, p = .0092), presence of clinical signs at presentation (HR 10.44, 95% CI 2.69–40.52, p = .0007), mitotic count >4 (HR 8.69, 95% CI 2.55–29.55, p = 0.0005), presence of multinucleation (HR 4.21, 95% CI 1.35–13.18, p = .0135), use of neoadjuvant and adjuvant chemotherapy (HR 7.16, 95% CI 1.26–40.73, p = .0266). The same factors, together with increasing tumour dimensions, were predictive for shorter progression-free survival (PFS), including increasing age (p = .0012), presence of clinical signs at presentation (p = .0045), increasing tumour dimensions (p = .0004), MC > 4 (p = .0004), presence of multinucleation (p = .0282), use of neoadjuvant and adjuvant chemotherapy (p = .0485). No variables remained significant for overall survival using multivariate analysis. There was a longer survival in cases where chemotherapy was not required (HR 0.14, 95% CI 0.03–0.68, p = .0148), and this variable remained significant for PFS on multivariate analysis (HR 0.13, 95% CI 0.02–0.76, p = .02). In conclusion, our study suggests that dogs with SC MCTs, in the absence of negative prognostic factors, may have a prolonged survival when treated with surgery alone. Further studies are needed to clarify the role of adjuvant treatment for biologically aggressive SC MCTs in dogs.     

Increased expression of tissue inhibitor of metalloproteinase‐1 correlates with improved outcome in canine cutaneous mast cell tumours

Canine mast cell tumour (MCT) is a biologically heterogeneous disease. The extracellular matrix degradation promoted by matrix metalloproteinases (MMPs) has been studied in an attempt to elucidate the mechanisms involved in the biological behaviour of tumours. The aim of this study was to characterize the expression of MMP‐2 and ‐9 and tissue inhibitors of metalloproteinase (TIMP)‐1 and ‐2 in canine cutaneous MCTs and to evaluate their prognostic values. Immunohistochemical staining for MMP‐2, MMP‐9, TIMP‐2 and TIMP‐1 was performed in 46 canine cases of MCTs. TIMP‐1 expression showed an independent prognostic value for post‐surgical survival and disease‐related mortality. Dogs with MCTs showing less than 22.9% mast cell TIMP‐1 positivity were more prone to die because of the disease and had a shorter post‐surgical survival. This article suggests the involvement of TIMP‐1 in MCT progression, by contributing to a good outcome in patients with MCTs.     

Efficacy and safety of electrochemotherapy combined with peritumoral IL‐12 gene electrotransfer of canine mast cell tumours

Electrochemotherapy combined with peritumoral interleukin‐12 (IL‐12) gene electrotransfer was used for treatment of mast cell tumours in 18 client‐owned dogs. Local tumour control, recurrence rate, as well as safety of combined therapy were evaluated. One month after the therapy, no side effects were recorded and good local tumour control was observed with high complete responses rate which even increased during the observation period to 72%. IL‐12 gene electrotransfer resulted in 78% of patients with detectable serum IFN‐γ and/or IL‐12 levels. In the treated tumours vascular changes as well as minimal T‐lymphocytes infiltration was observed. After 1 week, the plasmid DNA was not detected intra‐ or peritumorally and no horizontal gene transfer was observed. In summary, our study demonstrates high antitumour efficacy of electrochemotherapy combined with IL‐12 electrotransfer, which also prevented recurrences or distant metastases, as well as its safety and feasibility in treatment of canine mast cell tumours.     

Retrospective analysis of factors affecting clinical outcome following CHOP‐based chemotherapy in dogs with primary nodal diffuse large B‐cell lymphoma

Numerous factors are known to affect the prognosis of dogs with chemotherapy‐treated lymphomas. However, prognostic factors for dogs with specific subtypes of lymphoma are less clearly defined. The objective of this study was to identify prognostic factors for dogs receiving CHOP‐based chemotherapy for primary nodal diffuse large B‐cell lymphoma (DLBCL). Medical records of dogs treated for DLBCL at the Purdue Veterinary Teaching Hospital (PUVTH) from 2006 to 2016 were reviewed. Factors potentially related to prognosis were analysed using multivariable statistical methods. Ninety‐eight dogs were included in the study. Best overall response to chemotherapy was complete remission in 80 dogs (81.6%) and partial remission in 18 dogs (18.4%). Median progression‐free survival (PFS) for the entire population was 252 days (range 19‐1068). Factors significantly associated with achieving partial (rather than complete) remission following CHOP included presence of thrombocytopenia at diagnosis (OR 6.88; 95% CI 1.98‐23.93; P = .002), baseline serum globulin concentration (OR 2.63; 95% CI 1.03‐6.75; P = .044), and age at diagnosis (OR 1.36; 95% CI 1.08‐1.71; P = .009). Factors significantly associated with PFS in the lowest quartile (≤93 days) included presence of thrombocytopenia at diagnosis (OR 8.72; 95% CI 1.54‐49.33; P = .014), age at diagnosis (OR 1.47; 95% CI 1.12‐1.94; P = .005), and baseline neutrophil count (OR 1.18; 95% CI 1.02‐1.37; P = .025). Presence of thrombocytopenia, greater age, higher neutrophil count, and higher serum globulin concentration all may be associated with a particularly poor outcome in dogs receiving CHOP‐based chemotherapy for DLBCL.     

High COX‐2 expression in canine mast cell tumours is associated with proliferation,angiogenesis and decreased overall survival

COX‐2 overexpression is associated with several hallmarks of carcinogenesis such as proliferation, angiogenesis, invasion and metastasis. Fifty cases of canine mast cell tumours (MCT) were retrospectively evaluated and submitted to immunohistochemistry for COX‐2, CD31, Ki‐67, MAC‐387 and CD3. Furthermore its relationship with clinicopathological variables and overall survival (OS) was analysed. COX‐2 intensity (P = 0.016), but not COX‐2 extension nor score was associated with decreased OS and higher grades of malignancy according to Patnaik (P = 0.002) and Kiupel (P < 0.001) grading systems. Cox‐2 intensity was also associated with higher Ki‐67 scores (P = 0.009), higher mitotic index (P = 0.022) and higher microvascularization density (P = 0.045). No association was observed for COX‐2 intensity and CD3‐T lymphocyte (P = 0.377) and macrophage infiltration (P = 0.261) by MAC‐387 immunollabelling, suggesting an active role of COX‐2 in MCT oncogenesis mainly through proliferation and angiogenesis stimulation making it a potentially clinical relevant prognosis marker and therapeutic target.     

Prognostic and predictive significance of KIT protein expression and c‐kit gene mutation in canine cutaneous mast cell tumours: A consensus of the Oncology‐Pathology Working Group

One of the primary objectives of the Oncology‐Pathology Working Group (OPWG), a joint initiative of the Veterinary Cancer Society and the American College of Veterinary Pathologists, is for oncologists and pathologists to collaboratively generate consensus documents to standardize aspects of and provide guidelines for oncologic pathology. Consensus is established through critical review of peer‐reviewed literature relevant to a subgroup's particular focus. Subsequent acceptance and approval of the document by the OPWG membership at large establishes consensus. The intent of this publication is to help educate practitioners and pathologists on the value of diagnostics related to the KIT receptor tyrosine kinase for canine cutaneous mast cell tumours and to provide a guide for the use of these tests in veterinary medicine. This document represents the opinions of the OPWG and the authors and does not constitute a formal endorsement by the American College of Veterinary Pathologists or the Veterinary Cancer Society.     

Comparative clinical study of canine and feline total blood cell count results with seven in‐clinic and two commercial laboratory hematology analyzers

Background: A CBC is an integral part of the assessment of health and disease in companion animals. While in the past newer technologies for CBC analysis were limited to large clinical pathology laboratories, several smaller and affordable automated hematology analyzers have been developed for in‐clinic use. Objectives: The purpose of this study was to compare CBC results generated by 7 in‐clinic laser‐ and impedance‐based hematology instruments and 2 commercial laboratory analyzers. Methods: Over a 3‐month period, fresh EDTA‐anticoagulated blood samples from healthy and diseased dogs (n=260) and cats (n=110) were analyzed on the LaserCyte, ForCyte, MS45, Heska CBC, Scil Vet ABC, VetScan HMT, QBC Vet Autoread, CELL‐DYN 3500, and ADVIA 120 analyzers. Results were compared by regression correlation (linear, Deming, Passing‐Bablok) and Bland–Altman bias plots using the ADVIA as the criterion standard for all analytes except HCT, which was compared with manual PCV. Precision, linearity, and carryover also were evaluated. Results: For most analytes, the in‐clinic analyzers and the CELL‐DYN performed similarly and correlated well with the ADVIA. The biases ranged from ?0.6 to 2.4 × 10⁹/L for WBC count, 0 to 0.9 × 10¹²/L for RBC count, ?1.5 to 0.7 g/dL for hemoglobin concentration, ?4.3 to 8.3 fL for MCV, and ?69.3 to 77.2 × 10⁹/L for platelet count. Compared with PCV, the HCT on most analyzers had a bias from 0.1% to 7.2%. Canine reticulocyte counts on the LaserCyte and ForCyte correlated but had a negative bias compared with those on the ADVIA. Precision, linearity, and carryover results were excellent for most analyzers. Conclusions: Total WBC and RBC counts were acceptable on all in‐clinic hematology instruments studied, with limitations for some RBC parameters and platelet counts. Together with evaluation of a blood film, these in‐clinic instruments can provide useful information on canine and feline patients in veterinary practices.     

A combination chemotherapy protocol with MOPP and CCNU consolidation (Tufts VELCAP-SC) for the treatment of canine lymphoma

A chemotherapy protocol using a consolidation phase of alkylating agents was used for treating 94 dogs with lymphoma. Fifty‐seven percent of dogs were in stage V, 63% were ill and 38% had T‐cell lymphoma. The complete remission (CR) rate was 70% and is comparable to results achieved with previously published chemotherapy protocols. Anorexia predicted the remission; of the 40 dogs without anorexia, 35 (88%) achieved CR whereas of 52 dogs with anorexia, 30 (58%) achieved CR. Median first CR duration was 168 days and 1‐ and 2‐year CR rates were 17.4 and 15.5%, respectively. Platelet count affected length of first CR, with a 53.2% reduced chance of coming out of remission with each log increase in platelet count. Median survival time was 302 days. One and 2‐year survival rates were 44 and 13%, respectively. Anorexia and no dose reduction of any drug were independent negative variables. Of 93 dogs with toxicity data, 65 dogs (70%) required a dose reduction. Cyclophosphamide was most commonly reduced with reductions in 31 (38%) of 82 dogs. A dose reduction was significantly more likely in dogs with B‐cell lymphoma than in those with T‐cell lymphoma.     

Three‐dimensional conformal versus non‐graphic radiation treatment planning for apocrine gland adenocarcinoma of the anal sac in 18 dogs (2002–2007)

Differences in dose homogeneity and irradiated volumes of target and surrounding normal tissues between 3D conformal radiation treatment planning and simulated non‐graphic manual treatment planning were evaluated in 18 dogs with apocrine gland adenocarcinoma of the anal sac. Overall, 3D conformal treatment planning resulted in more homogenous dose distribution to target tissues with lower hot spots and dose ranges. Dose homogeneity and guarantee of not under‐dosing target tissues with 3D conformal planning came at the cost, however, of delivering greater mean doses of radiation and of irradiating greater volumes of surrounding normal tissue structures.     

Evaluation of a multi‐agent chemotherapy protocol combining lomustine,procarbazine and prednisolone (LPP) for the treatment of relapsed canine non‐Hodgkin high‐grade lymphomas

The standard of care treatment for canine lymphoma is multi‐agent chemotherapy containing prednisolone, cyclophosphamide, vincristine and an anthracycline such as doxorubicin (CHOP) or epirubicin (CEOP). Lomustine, vincristine, procarbazine, and prednisone (LOPP) has been evaluated as a rescue, with encouraging results; however, resistance to vincristine is likely in patients relapsing on CHOP/CEOP, and this agent may enhance LOPP toxicity without improving efficacy. The aim of this study was to evaluate responses to a modified‐LOPP protocol that does not include vincristine (LPP) and is administered on a 21‐day cycle. Medical records of dogs with high‐grade multicentric lymphoma from 2012 to 2017 were reviewed. Dogs with relapsed lymphoma that received LPP as a rescue protocol were enrolled. Response, time from initiation to discontinuation (TTD) and toxicity of LPP were assessed. Forty‐one dogs were included. Twenty‐five dogs (61%) responded to LPP including 12 complete responses (CR) and 13 partial responses (PR). Responders had a significantly longer TTD (P < .001) compared to non‐responders with 84 days for CR and 58 days for PR. Neutropenia was documented in 20 dogs (57%): 12 grade I to II, 8 grade III to IV. Thrombocytopenia was infrequent (20%): 5 grade I to II, 2 grade III to IV. Twelve dogs developed gastrointestinal toxicity (30%): 10 grade I to II and 2 grade III. Nineteen dogs had elevated ALT (59%): 9 grade I to II, 10 grade III to IV. Treatment was discontinued due to toxicity in 8 dogs (19%). The LPP protocol shows acceptable efficacy and toxicity‐profile and minimizes in‐hospital procedures.     

A randomized, double-blind, placebo-controlled trial to investigate the efficacy and safety of a Chinese herbal product (P07P) for the treatment of canine atopic dermatitis

A randomized, double-blind, placebo-controlled trial of P07P, a product derived from a traditional Chinese herbal remedy, was undertaken in 50 dogs with atopic dermatitis. Owners recorded a daily itch score for 4-14 days before treatment and during treatment. Packets of powder containing P07P or placebo were added to the food once daily for 8 weeks. Dogs were assessed for erythema, surface damage, overall coat condition and seborrhoea by the same investigator, as well as for pruritus and general demeanour, at 0 (visit 2), 28 (visit 3) and 56 (visit 4) days of treatment or at withdrawal. Investigator and owner assessments of response were recorded after 28 and 56 days of treatment or at withdrawal. The predefined primary outcome measure was the owners' assessment of response at the end of treatment. Nine of the 24 dogs (37.5%) in the P07P group but only 3 of the 23 dogs (13%) in the placebo group were considered to have improved, but this difference was not statistically significant (P = 0.09). There was a significantly higher withdrawal rate due to worsening of condition in the placebo group (P = 0.04). Mean daily itch score in the second 28-day period of the study was significantly higher than baseline in the placebo group (P = 0.01) but not in the P07P group (P = 0.30). Pruritus scores showed a significant deterioration from baseline at the final visit in the placebo group (P = 0.01) but not in the P07P group (P = 1.00). There was a significant difference between the groups in change from baseline in erythema score at visit 3 (P = 0.05). There were no significant differences (P > 0.05) in surface damage, seborrhoea, overall coat condition and general demeanour scores within or between the groups throughout the study. The product was well tolerated with no severe or serious adverse events recorded. P07P may be beneficial as a novel nonsteroidal therapy for the management of dogs with atopic dermatitis.