A retrospective analysis of chemotherapy switch suggests improved outcome in surgically removed,biologically aggressive canine haemangiosarcoma

Haemangiosarcoma (HSA) has an aggressive biological behaviour and carries a poor prognosis, with less than 10% of treated dogs surviving longer than 1 year. In this retrospective study a varied metronomic chemotherapy (MC) regimen preceded by adjuvant doxorubicin‐based maximum‐tolerated dose chemotherapy (MTDC) was compared with MTDC, in terms of efficacy [time to metastasis, (TTM) and survival time (ST)] and safety in dogs with biologically aggressive HSA. Dogs were eligible if they had no metastasis after MTDC and received either no further chemotherapy or MC maintenance. Twelve dogs received MTDC, and 10 received MC thereafter. Median TTM and ST were significantly longer for dogs receiving MTDC‐MC (not reached versus 150 days, P = 0.028; and not reached versus 168 days, P = 0.030, respectively). Treatment was well tolerated. MTDC followed by MC is safe and suggests improved TTM and ST in dogs with surgically removed, biologically aggressive HSA that are treated in the microscopic setting.     

The Utrecht Score: A novel histopathological scoring system to assess the prognosis of dogs with cortisol‐secreting adrenocortical tumours

A cortisol‐secreting adrenocortical tumour (ACT) is the cause of naturally occurring canine hypercortisolism in approximately 15% to 20% of cases. The differentiation between an adrenocortical adenoma and carcinoma is usually based on histopathology. However, histopathological parameters have never been linked to the dogs' survival. Moreover, in human medicine the inter‐observer variability of some histopathological parameters that are used for ACTs is high. The objective of this study was to establish a reliable and easy‐to‐use histopathological scoring system for cortisol‐secreting ACTs that can assess the prognosis of dogs after adrenalectomy. Cortisol‐secreting ACTs of 50 dogs, collected between 2002 and 2015, were included in this study. Twenty histopathological features were assessed by one veterinary pathologist and one resident in veterinary pathology. In addition, the Ki67 proliferation index was assessed by two observers. Only parameters with intra‐ and inter‐observer agreement scores (intra‐class correlation or Cohen's kappa coefficient) of ≥0.40 were included in survival analyses. Use of multivariate forward stepwise regression analysis with associated hazard ratios led us to a scoring system which we call the Utrecht score: the Ki67 proliferation index, +4 if more than 33% of the tumour cells have clear/vacuolated cytoplasm and + 3 if necrosis is present. Using cut‐off values of 6 and 11, we could distinguish three groups that had significantly shorter survival times with increasing Utrecht scores. We conclude that the Utrecht score can be used to assess the prognosis of dogs with cortisol‐secreting ACTs after adrenalectomy, which can help to select high‐risk dogs that might benefit from adjuvant treatment or additional monitoring.     

PCNA and grade in 13 canine oral squamous cell carcinomas: association with prognosis

This study evaluated the prognosis factors of age, tumour size, anatomic location, histological grade and proliferating cell nuclear antigen (PCNA) expression in 13 dogs with oral squamous cell carcinoma (OSCC) with bone invasion and without signs of lymph node or distant metastasis. All animals were treated with radical excision performed with at least 1 cm margin, based on computed tomography images. In the 2‐year follow‐up, median disease‐free survival was 138 days for dogs with grade 3 tumours and was not reached for those with grade 2 tumours. Grade 3 tumours and PCNA labelling index ≥65% were related with a shorter disease‐free survival time and consequently poor prognosis (p = 0.003 and p = 0.034, respectively). Mean PCNA labelling index was significantly higher in recurrent cases (p = 0.011). Histological grade and PCNA expression may be important prognosis factors in canine OSCC.     

Biological behaviour of canine mandibular osteosarcoma. A retrospective study of 50 cases (1999–2007)

The purpose of this retrospective study was to describe the biological behaviour of canine mandibular osteosarcoma (OSA) and to examine factors for their impact on metastasis‐free interval (MFI) and survival time (ST). Records from dogs treated with mandibulectomy for OSA (1999–2007) were reviewed. Archived tumour samples were evaluated for mitotic index (MI) and tumour grade. Fifty dogs were included, 21 received chemotherapy. Twenty‐nine dogs (58%) developed metastatic disease. The median MFI was 627 days, and median ST was 525 days. In univariate analysis MI > 40 was prognostic for decreased MFI and ST. Grade also influenced MFI and ST, with 5/21 (24%) dogs with grade II/III tumours metastasis‐free at one year versus 16/22 (72%) dogs with grade I tumours (P = 0.002); and 5/21 (24%) dogs with grade II/III tumours alive versus 17/22 (77%) dogs with grade I tumours (P = 0.001). In multivariate analysis, histological grade and adjuvant chemotherapy were prognostic for MFI and ST.     

Treatment of canine mast cell tumours with vinblastine, cyclophosphamide and prednisone: 35 cases (1997–2004)

The purpose of this retrospective study was to determine the efficacy and toxicity of a combined protocol of vinblastine, cyclophosphamide and prednisone (VCP) in 35 dogs with mast cell tumours (MCTs). Eleven dogs had measurable disease (group 1) and 24 dogs had incompletely excised MCT or were at high risk for metastasis (group 2). Five patients in group 1 achieved complete response, two partial responses, two stable diseases and two progressive diseases. The median progression‐free survival time (PFST) for group 1 and 2 dogs was 74 and 865 days, respectively. The median overall survival time (OST) for group 1 and 2 dogs was 145 and >2092 days, respectively. Significant negative multivariate prognostic factors included macroscopic disease and reduced vinblastine (VBL) treatments for PFST, and presence of MCT in bone marrow analysis, Patnaik grade III MCT and reduced VBL treatments for OST. Toxicity was infrequent and self‐limiting. This study suggests that the VCP protocol should be considered as an option in the treatment of MCT in dogs.     

Aggressive local therapy combined with systemic chemotherapy provides long‐term control in grade II stage 2 canine mast cell tumour: 21 cases (1999–2012)

This retrospective case series evaluates the outcome of 21 dogs with grade II stage 2 mast cell tumour (MCT) treated with adequate local therapy and adjuvant systemic chemotherapy (prednisone, vinblastine and CCNU). The median survival for all dogs was 1359 days (range, 188–2340). Median disease‐free interval was 2120 days (149–2325 days). Dogs treated with surgery and chemotherapy had shorter survival (median, 1103 days; 188–2010 days) than those that underwent surgery, radiation therapy and chemotherapy as part of their treatment (median, 2056 days; 300–2340 days). Two patients had local recurrence in the radiation field and four patients had de novo MCT. Distant metastasis was not observed in any dogs. The results of this study suggest that, in the presence of loco‐regional lymph node metastasis in grade II MCT, the use of prednisone, vinblastine and CCNU after adequate local‐regional therapy can provide a median survival in excess of 40 months.     

Retrospective outcome evaluation for dogs with surgically excised,solitary Kiupel high‐grade,cutaneous mast cell tumours

Published outcomes for dogs with specifically high‐grade mast cell tumours (MCTs), controlled for clinical stage, are few. Clinical outcomes for 49 dogs with Kiupel high‐grade, clinical stage I, cutaneous MCTs were evaluated. Median survival time (MST) was 1046 days; 1 and 2‐year survival rates were 79.3% and 72.9%, respectively. At study end 24 dogs had died, 23 dogs were alive (median follow‐up 980 days) and 2 dogs were lost to follow‐up. Death was considered MCT‐related in 14 of 20 dogs with a known cause of death. Local tumour recurrence developed in nine dogs (18.4%); regional lymph node metastasis occurred in six dogs (12.2%); and a new MCT developed in 15 dogs (30.1%). Tumour location, histologic margin size and use of chemotherapy did not affect MST; increasing mitotic count (P = .001) and increasing tumour diameter (P = .024) were independently negatively prognostic. Six dogs that developed lymph node metastasis after surgery had worse MST (451 days) than 42 dogs that did not develop metastasis (1645 days); (P < .001). Our study suggests that dogs with local surgical control of clinical stage I histologically high Kiupel grade cutaneous MCT may have a long survival time; especially those with smaller tumours and a lower mitotic count. Our results suggest that evaluation of staging information and mitotic count may be equally helpful as histologic grading when making a prognosis; and highlight the importance of not relying on histologic grade alone when predicting survival for dogs with MCT.     

The animal‐dependent risk factors in canine T‐cell lymphomas

Malignant lymphomas are one of the most common malignancies occurring in dogs; among them T‐cell tumours are less commonly recognized. Recently, many authors have recommended cytology as a sufficient diagnostic method for canine lymphomas, especially if supported by immunocytochemistry or flow cytometry. The aim of the study was to characterize animal‐dependent risk factors in canine T‐cell lymphomas (TCLs) in Poland, including specific cytological subtypes. Determination of the type and subtype of the tumour was made based on the updated Kiel cytological classification adopted for dogs as previously described. Two breeds turned out predisposed to TCL (dog de Bordeaux and Boxer) while no predisposition to B‐cell lymphoma could be evidenced. Dogs with low‐grade lymphoma were significantly older than those with high‐grade lymphoma.     

Biologic Behavior and Clinical Outcome of 25 Dogs with Canine Appendicular Chondrosarcoma Treated by Amputation: A Veterinary Society of Surgical Oncology Retrospective Study

Objective— To characterize biologic behavior, clinical outcome, and effect of histologic grade on prognosis for dogs with appendicular chondrosarcoma treated by amputation alone. Study Design— Case series. Animals— Dogs (n=25) with appendicular chondrosarcoma. Methods— Medical records were searched to identify dogs with appendicular chondrosarcoma treated by limb amputation alone. Information recorded included signalment, anatomic location, radiographic appearance, and development of metastasis. Histopathologic diagnosis was confirmed and graded (1, 2, or 3). Survival curves were generated by the Kaplan–Meier method and the association between covariates (gender, age, weight, and tumor grade) and survival were evaluated using the univariate proportional hazards model. Results— Histopathology slides were available for 25 dogs. Rates of pulmonary metastasis were as follows: grade 1–0%, grade 2–31%, and grade 3–50%. Overall median survival time (MST) was 979 days. Age, weight, and sex were not significantly associated with survival (P=.16; .33; and .31, respectively). Survival was significantly associated with tumor grade (P=.008), with dogs with tumor grade of 1, 2, and 3 having MSTs of 6, 2.7, and 0.9 years, respectively. Conclusion— Canine appendicular chondrosarcoma can be treated effectively with amputation alone. Low to intermediate grade chondrosarcoma has a good prognosis, whereas high‐grade tumors appear to behave aggressively. Clinical Relevance— The overall prognosis for appendicular chondrosarcoma is better than that of appendicular osteosarcoma treated by amputation alone or in combination with chemotherapy.     

Timely adjuvant chemotherapy improves outcome in dogs with non-metastatic splenic hemangiosarcoma undergoing splenectomy

Timely delivery of adjuvant chemotherapy has been shown to be advantageous in many human cancers and canine osteosarcoma. Adjuvant chemotherapy has been shown to improve outcome for canine splenic hemangiosarcoma. The aim of this retrospective study was to investigate whether timely adjuvant chemotherapy administration resulted in better outcome in dogs with non-metastatic splenic hemangiosarcoma undergoing splenectomy. Medical records were searched for dogs with non-metastatic, splenic hemangiosarcoma that received splenectomy and adjuvant chemotherapy. The number of days from surgery to the first chemotherapy dose (StoC) was evaluated to identify the cut-off value associated with the best survival advantage. StoC and other possible prognostic factors were tested for influence on time to metastasis (TTM) and overall survival (OS). Seventy dogs were included. Median StoC was 20 days (range: 4–70). The time interval associated with the greatest survival benefit was 21 days. Median TTM and OS of dogs with StoC ≤ 21 days were significantly longer than those with StoC >21 days (TTM: 163 vs. 118 days, p = .001; OS: 238 vs. 146 days, p < .001). On multivariable analysis, StoC >21 days was the only variable significantly associated with increased risk of tumour progression (HR 2.1, p = .010) and death (HR 2.3; p = .008). Starting adjuvant chemotherapy within 21 days of surgery may be associated with a survival benefit in dogs with non-metastatic splenic hemangiosarcoma, possibly due to the early targeting of newly recruited metastatic cells after surgery.     

Adjuvant medical therapy provides no therapeutic benefit in the treatment of dogs with low‐grade mast cell tumours and early nodal metastasis undergoing surgery

Lymph node (LN) metastasis is a negative prognostic factor in dogs with cutaneous mast cell tumours (cMCTs). While elective lymphadenectomy of metastatic LNs improves outcome, the benefit of adjuvant medical therapy in dogs with early metastatic (HN2) LNs is debated. The aim of this retrospective multicentre study was to evaluate the therapeutic benefit of adjuvant medical therapy following surgical removal of the primary low‐grade cMCT (Patnaik grade 1‐2 and Kiupel low‐grade) and lymphadenectomy of HN2 LNs by analysing survival rates and patterns of recurrence. Seventy‐three dogs were included: 42 received adjuvant medical treatment (chemotherapy and/or kinase inhibitors), and 31 did not. The median follow‐up time for medically treated dogs was 619 days: two experienced local recurrence, three nodal relapse and four distant relapse. For dogs undergoing surgery only, the median follow‐up time was 545 days. None of them experienced local recurrence, nodal, or distant relapse. Time to progression was significantly shorter in dogs receiving adjuvant medical treatment (P = .021). A similar tendency was observed for overall survival (P = .056). The current study shows that dogs with low‐grade cMCTs, that undergo surgical excision of the primary tumour and elective lymphadenectomy of the HN2 regional LN harbour a good prognosis. The use of adjuvant medical treatment in these dogs does not seem to provide any benefit in terms of progression and survival.     

Ultrasound is a poor predictor of early or overt liver or spleen metastasis in dogs with high‐risk mast cell tumours

Conflicting evidence exists regarding the importance of routine abdominal ultrasound (US) with hepatic and splenic fine needle aspiration (FNA) cytology during staging of canine mast cell tumours (MCT). The objective of this study was to correlate ultrasonographic and cytologic findings in dogs with strictly defined high‐risk MCTs and to determine the influence on outcome. Our hypothesis was that US poorly predicts visceral metastasis in high‐risk MCTs and that early metastasis is associated with improved outcome when compared to overt metastasis. US of liver and spleen correlated to cytologic results, categorized as no metastasis, early metastasis or overt metastasis. Of 82 dogs prospectively enrolled, 18% had early visceral metastasis and 7% had overt metastasis on cytology; 67% with visceral metastasis had regional LN metastasis. US was a poor predictor of metastasis with sensitivity, specificity, positive predictive value and negative predictive value for the spleen of 67%, 68%, 21% and 94%, respectively and for the liver of 29%, 93%, 56% and 82%, respectively. Median time to progression (TTP) for dogs with no metastasis, early metastasis and overt metastasis was not reached, 305 and 69 days, respectively (P < .001). Median survival time (MST) for the 3 groups were not reached, 322 and 81 days, respectively (P < .001). High Patnaik or Kiupel grade, early metastasis, overt metastasis and adequate local control were significantly associated with outcome. Early visceral metastasis was associated with poorer outcome compared to dogs without metastasis, however, a subset of dogs experienced long‐term control.     

Canine anaesthetic death in Spain: a multicentre prospective cohort study of 2012 cases

ObjectiveTo study current perianaesthetic mortality in dogs in Spain and to identify the main risk factors predisposing to perianaesthetic mortality in our country.Study designA multicentre prospective cohort study.Animal populationDogs anaesthetised for different surgical and diagnostic procedures at 39 Spanish veterinary clinics between February 2007 and March 2008.MethodsData of patients, procedures and anaesthetic management were recorded. Anaesthetic death was defined as perioperative death within 24 hours of the procedure end. A multivariate study evaluated perinanaesthetic death using logistic binary regression models with the Wald technique.Results2012 animals were included in the analyses. Twenty‐six dogs died. The global mortality rate was 1.29% (95% Confidence interval (95% CI): 0.88–1.89%). ASA I‐II was 0.33% (95 CI: 0.14–0.78%); ASA III‐V was 4.06% (95% CI: 2.67–6.13%). Most deaths occurred during the post‐operative period (20 dogs, 77%). The multivariate analysis revealed that high ASA grade was associated with an increased risk of mortality. The use of opioids plus NSAIDs during anaesthesia was related with a decrease of the risk.ConclusionsPerianaesthetic mortality in dogs in Spain was 1.29% (95% CI: 0.88–1.89%). ASA grade was the main prognostic factor of likelihood of death. The use of some analgesics (opioids and NSAIDs) in the perioperative period was associated with reduced odds of death and may be protective.Clinical relevanceEvaluation and stabilisation of patients before interventions may help lower risk of death during the anaesthesia. In addition to their use for welfare purposes, analgesics may be beneficial in reducing anaesthetic‐related deaths.     

Outcome and prognostic factors following adjuvant prednisone/vinblastine chemotherapy for high-risk canine mast cell tumour: 61 cases

The medical records of 61 dogs with MCT at high risk for metastasis that were treated with prednisone and VBL following excision+/-radiation therapy were reviewed, and median disease-free interval (DFI), median overall survival time (OS) and prognostic factors assessed. Adverse effects, mostly mild, were noted in 26% of patients, usually after the first VBL dose. 6.5% experienced severe neutropenia. The DFI was 1305 days, and the OS was not reached, with 65% alive at 3 years. 100% of dogs with "high-risk" grade II MCT were alive at 3 years. The OS for dogs with grade III MCT was 1374 days. Histologic grade, location (mucous membrane vs. skin) and use of prophylactic nodal irradiation predicted outcome. Prednisone and VBL chemotherapy is well tolerated, and results in good outcomes following surgery in dogs with MCT at high risk for metastasis. High-grade and mucocutaneous tumors had a worse outcome, and the use of prophylactic nodal irradiation appeared to improve outcome in this group of dogs.     

Evaluation of prognostic factors associated with outcome in dogs with multiple cutaneous mast cell tumors treated with surgery with and without adjuvant treatment: 54 cases (1998-2004)

OBJECTIVE: To evaluate prognostic factors associated with outcome of dogs with multiple cutaneous mast cell tumors (MCTs) treated with surgery with or without adjuvant treatment. DESIGN: Retrospective case series. ANIMALS: 54 dogs with a minimum of 2 simultaneous, histologically confirmed cutaneous MCTs that had been excised and had adequate staging and follow-up data. PROCEDURE: Medical records from 1998 to 2004 were examined. Outcome was assessed with the Kaplan-Meier product-limit method and log-rank analysis. Prognostic factors evaluated included signalment; number, histologic grade, location, size, local recurrence, and de novo development of MCTs; quality of surgical margins; clinical signs at the time of diagnosis; and use of adjuvant treatment. RESULTS: Medical records of 54 dogs with 153 tumors were included. Median follow-up time was 658 days. Median disease-free interval (1,917 days; range, 11 to 1,917 days) and median survival time (1,917 days; range, 14 to 1,917 days) were not yet reached. The 1- year and 2- to 5-year survival rates were 87% and 85%, respectively. The overall rate of metastasis was 15%. Factors that negatively influenced survival time in the univariate analysis included incomplete excision, local recurrence, size > 3 cm, clinical signs at the time of diagnosis, and use of adjuvant treatment. Presence of clinical signs at the time of diagnosis was the only negative prognostic factor for disease-free interval detected in the multivariate analysis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that multiple cutaneous MCTs in dogs are associated with a low rate of metastasis and a good prognosis for long-term survival with adequate excision of all MCTs.     

Association of argyrophilic nucleolar organizing regions, Ki-67, and proliferating cell nuclear antigen scores with histologic grade and survival in dogs with soft tissue sarcomas: 60 cases (1996-2002)

OBJECTIVE: To determine whether argyrophilic nucleolar organizing regions (AgNORs), Ki-67, and proliferating cell nuclear antigen (PCNA) scores were associated with histologic grade and survival in dogs with soft tissue sarcomas (STSs). DESIGN: Retrospective study. ANIMALS: 60 dogs with STSs. PROCEDURE: Medical records were examined and histologic specimens were reviewed. Tissue specimens obtained from archival materials were used to prepare sections for histologic staining for AgNOR and immunohistochemical staining for Ki-67 and PCNA labeling. Follow-up monitoring was obtained by reevaluation or telephone conversations with referring veterinarians or owners. RESULTS: 27 (45%) STSs were grade 1, 23 (38%) were grade 2, and 10 (17%) were grade 3. The mean and median AgNOR, Ki-67, and PCNA scores were determined, and significant positive associations among AgNOR and Ki-67 scores with histologic grade and mitotic score were detected. Fifty-four dogs had adequate follow-up examinations and were included in survival analysis and evaluation of prognostic factors. Overall median survival time was > 1,306 days. Twelve of 54 (22%) dogs died of tumor-related causes. Metastatic disease developed in 8 of 54 (15%) dogs. Results of univariate analysis indicated that increased mitotic score, increased AgNOR score, increased Ki-67 score, incomplete surgical margins, noncurative intent surgery, Ki-67 score greater than the median Ki-67 score, and AgNOR score greater than the median AgNOR score were prognostic factors for decreased survival time. Results of multivariate analysis indicated that increased AgNOR score was the only prognostic factor for decreased survival time. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that AgNORs and possibly Ki-67 should be routinely evaluated with histologic grading for STSs in dogs.     

Association of Ki67 index with prognosis for intermediate‐grade canine cutaneous mast cell tumours*

Intermediate‐grade mast cell tumours (MCT) represent a heterogeneous population of tumours. The prognosis for the majority of dogs is excellent following surgical excision, but a minority die because of their disease. A previous study identified Ki67 expression as a predictor of prognosis in all three grades of MCT. The purpose of this study was to validate those results in a new group of dogs, with intermediate‐grade MCT only. Ki67 immunohistochemistry was performed on intermediate‐grade MCT from 163 dogs with known outcome. Digital microscopy images were taken from each tumour, and an index calculated of Ki67‐positive cells. Ki67 index as a binary variable with a cut‐off value of 1.8% was confirmed to be associated with prognosis (hazard ratio = 19.1, P < 0.0001) for this cohort of dogs. The 1‐year, 2‐year and 3‐year survival probabilities (with standard errors) of 127 dogs with a Ki67 index ≤1.8% were [0.95 (0.024), similar for all] and for 36 dogs with a Ki67 index >1.8% were 0.54 (0.100), 0.45 (0.101) and 0.33 (0.104), respectively.     

Prognostic significance of Ki67 evaluated by flow cytometry in dogs with high‐grade B‐cell lymphoma

Ki67 can discriminate between high‐ and low‐grade canine lymphomas, but its prognostic role in specific subtypes of the neoplasm is unknown. We assessed the prognostic significance of Ki67% (percentage of Ki67‐positive cells), evaluated by flow cytometry, in 40 dogs with high‐grade B‐cell lymphoma, treated with a modified Wisconsin–Madison protocol (UW‐25). The following variables were investigated for association with lymphoma specific survival (LSS) and relapse free interval (RFI): Ki67%, breed, sex, age, stage, substage, complete remission (CR). By multivariate analysis, Ki67% (P = 0.009) and achievement of CR (P = 0.001) were independent prognostic factors for LSS. Dogs with intermediate Ki67% (20.1–40%) presented longer LSS and RFI (median = 866 and 428 days, respectively) than dogs with low (median = 42 days, P < 0.001; median = 159 days, P = 0.014) or high (median = 173 days, P = 0.038; median = 100 days, P = 0.126) values. Determination of Ki67 is a prognostic tool that improves the clinical usefulness of flow cytometric analysis in canine high‐grade B‐cell lymphoma.     

Correlation of histologic grading of canine mast cell tumors with Ki67/PCNA/AgNOR/c‐Kit scores: 38 cases (2002–2003)

Introduction: The Patnaik grading system for canine cutaneous MCT is currently one of the best determinants of prognosis; however, clinical outcome does not always correlate with histologic grade. The development of molecular markers offers a potential advantage and may complement subjective grading. The primary purpose of this study was to correlate histologic grading to Ki67/PCNA/AgNOR/c‐Kit scores. Methods: Thirty‐eight dogs with cutaneous MCT underwent surgical resection. Tumors were graded, with expansion of grade II MCT to low, medium (or II only) and high. For statistical purposes, MCT grade I, II (low, medium, high) and III were assigned a score of 1, 2, 3, 4, or 5, respectively. Sections were processed for AgNOR staining and expression of PCNA, Ki67 and c‐Kit as previously described (modified biotin‐strepavidin with DAB substrate). Paraffin‐embedded canine tissue arrays were used as positive and negative controls (primary antibody replaced with pre‐immune sera). Parametric statistical testing was performed using Statview statistical software with P ≤ .05 as significant. Results: There were 12, 20, 5 and 1 grade II low, grade II medium, grade II high and grade III MCT, respectively. The mean Ki67 score was 9.114 (median 8.0, range 1–28), mean PCNA score was 26.25 (median 24.0, range 5–65), mean AgNOR score was 1.499 (median 1.35, range 1.02–2.76) and c‐Kit scores were +1 (9/37), +2 (19/37) and +3 (9/37). With parametric statistical testing, significantly positive correlations were found for Ki67/Grade, PCNA/Grade, AgNOR/Grade, Ki67/PCNA, Ki67/AgNOR and PCNA/AgNOR (all P < .0001). No significant correlation was found for c‐Kit and grade; however, +3 c‐Kit scores had statistically significantly higher grades than +2 c‐Kit scores (P = .0458). Conclusions: Ki67/PCNA/AgNOR scores are positively correlated to grade in dogs with MCT. Further studies to correlate Ki67/PCNA/AgNOR/c‐Kit scores with clinical variables are ongoing.     

Diagnostic accuracy of pre‐treatment biopsy for grading soft tissue sarcomas in dogs

Histologic grade is an important prognostic factor for both local recurrence and metastatic potential with canine soft tissue sarcoma (STS). Pre‐treatment biopsy with identification of tumour grade may aid in prognostication and determination of surgical margins necessary for local control. The purpose of this study was to evaluate the grading accuracy of various pre‐treatment biopsy techniques (wedge, punch, needle‐core) for STS in dogs. Medical records of 68 dogs diagnosed with a STS via pre‐treatment biopsy and confirmed by excisional biopsy were evaluated. The concordance in grade between excisional and pre‐treatment biopsies was 59%. Of the 41% that lacked concordance, 29% of pre‐treatment biopsies underestimated and 12% overestimated grade. The method of pre‐treatment biopsy did not significantly effect grade concordance. Based on these data, needle‐core biopsy appears to be similar in accuracy compared to open biopsy, however, grading determined by pre‐treatment biopsy in general should be interpreted with caution.