Vinorelbine as First-Line Treatment in Stage IV Canine Primary Pulmonary Carcinoma.

Vinorelbine (VRL), a semi-synthetic vinca alkaloid commonly used in humans with advanced lung cancer, reaches high concentrations in the lung tissue, has proven antineoplastic activity and a low toxicity profile in dogs. Treatment-naïve, client-owned dogs with a cyto/histological diagnosis of advanced pulmonary carcinoma, selected from a laboratory database and previously subjected to imaging, were enrolled in the study. Vinorelbine (15 mg/m2) was administered weekly for 4 weeks and then fortnightly until progressive disease was documented. Staging work-up was repeated by means of diagnostic imaging after the fourth VRL (i.e., 28 days) and monthly thereafter; response to treatment was evaluated according to the RECIST. Toxicity was graded following the VCOGC group. Ten dogs met the inclusion criteria. Partial response was documented in eight dogs. Median time to progression was 88 days (range: 7-112) and median survival time for all dogs was 100 days (range 7-635). The most common side effect was neutropenia. The main limitations of the study were the absence of histological diagnosis in eight cases and the limited number of treated dogs. VRL is well tolerated with an adequate toxicity profile and may be useful in the management of advanced lung tumours if used as a first-line treatment strategy.

The Prognostic Role of Preoperative Hematological and Inflammatory Indices in Canine Appendicular Osteosarcoma.

Hematological indices play a prognostic role in human osteosarcoma (OSA), but data are limited in dogs. The aim of this retrospective multicentric cohort study was to investigate the prognostic significance of pre-operative hematological/inflammatory indices in a cohort of client-owned dogs with appendicular OSA receiving standardized treatment. Cut-offs associated with progression-free survival (PFS) for pre-operative hematological values/ratios were established using the minimal p-value approach. Historical prognostic factors were also assessed. Statistical analyses were performed for the whole population and after the exclusion of sighthounds. Fifty-nine dogs were included (13 were sighthounds). Multivariable analysis revealed that a low neutrophil count (<4.37 × 109/L, HR0.28, CI 95% 0.13-0.61, p = 0.001), a high red blood cell count (≥7.91, HR3.5, CI 95% 1.56-7.9, p = 0.002), and a proximal humerus location (HR3.0, CI 95% 1.48-6.1, p = 0.002) were associated with shorter PFS. In the sighthound-only population, only OSA location was significantly associated with PFS in univariable analysis. When sighthounds were excluded, a low neutrophil count, a low monocyte count, and a proximal humerus location were associated with shorter PFS, in multivariable analysis. Neutrophil count and possibly monocyte and red blood cell counts can be useful prognostic markers in canine OSA treated with amputation and adjuvant carboplatin. However, not all indices are appropriate in sighthounds.

Meloxicam in Combination with Mitoxantrone or Vinblastine as First-Line Treatment for Non-Resectable Urothelial Cell Carcinoma in Dogs.

Cyclooxygenase (COX) inhibitors have been demonstrated to have antitumour activity in canine urothelial cell carcinoma (UCC), given as a sole treatment or in combination with chemotherapy. The purpose of this retrospective multi-institutional study was to assess the efficacy of meloxicam in combination with mitoxantrone or vinblastine as a first-line treatment for non-resectable canine UCC. Gastrointestinal adverse effects (AEs) of these treatment combinations were also assessed. A total of 28 dogs met the inclusion criteria, 21/28 dogs received mitoxantrone and meloxicam, and 7/28 received vinblastine and meloxicam. Tumour response (TR) and AE were evaluated according to Veterinary Co-Operative Oncology Group (VCOG) criteria. The endpoint of the study was the time to tumour progression (TTP). The mitoxantrone-group induced 24% partial response and 62% stable disease, while the vinblastine-group induced 14% and 86%, respectively. Median TTP was 84 days (mitoxantrone and meloxicam, 70 days; and vinblastine and meloxicam, 178 days). The presence of metastatic disease significantly decreased TTP (p = 0.007). Gastrointestinal AEs were reported in 21.4% of the patients, with the most common being VCOG grade 1-2 diarrhoea. Meloxicam is a well-tolerated NSAID when combined with mitoxantrone or vinblastine as first-line treatment for non-resectable canine UCC.

Pre-operative neoadjuvant vinblastine-prednisolone in canine mast cell tumours: A single-centre retrospective cohort study.

Neoadjuvant chemotherapy can be used in canine mast cell tumours (MCTs) to optimise surgical margins or to enable marginal excision in challenging locations. The objective of this study was to describe the outcome of dogs with cutaneous and subcutaneous MCTs treated with neoadjuvant vinblastine-prednisolone (NA-VP). Records of treatment-naïve dogs with cutaneous/subcutaneous MCT that received NA-VP were reviewed including signalment, indication for NA-VP, staging results, clinical response, surgical data and histopathology reports. For dogs with post-operative follow-up ≥365 days, predictive factors for local recurrence (LR) were evaluated. Forty-four dogs were included. NA-VP was indicated to optimise surgical margins (group MARG) in 19 dogs (43.2%) and to enable surgery (group MORB) in 25 dogs (56.8%). Complete and partial response were documented in 40.9% of dogs and 30 dogs (68.2%) underwent surgery. The indication for NA-VP was significantly associated with undergoing surgery (p < .001) on multivariable analysis. Twelve (48%) and 18 dogs (94.7%) underwent surgery in the group MORB and MARG, respectively. Five dogs (16.7%) experienced wound dehiscence. Complete excision was achieved in 14 dogs (46.7%). In dogs undergoing surgery with ≥365 days of follow-up, LR was documented in five cases (20.8%). None of the factors analysed including mitotic count, completeness of excision and response to NA-VP were associated with LR; notably, LR occurred in 3/11 (27.2%) completely excised MCTs. In a pre-operative setting, NA-VP appears safe and could be beneficial in selected cases. Prognostic factors such as clinical response, mitotic count and completeness of excision should be interpreted with caution following NA-VP.

Case report: Severe, refractory hypoglycemia in a 9-year-old Brittany Spaniel with renal nephroblastoma.

A 9-year-old female spayed Brittany Spaniel presented for weakness and stumbling, and was diagnosed with severe hypoglycemia. An insulin to glucose ratio was not consistent with insulinoma as a cause for hypoglycemia. Diagnostic imaging (abdominal ultrasound and computed tomography) revealed a large left renal mass and a possible metastatic lesion in the right kidney. Glucagon therapy was initiated, but hypoglycemia was refractory to therapy. A left nephrectomy was performed and hypoglycemia subsequently resolved. Histopathology of the mass was consistent with nephroblastoma and immunohistochemistry for anti-insulin-like Growth Factor-2 (IGF-2) antibody revealed immunoreactivity in over 50% of the neoplastic cells. Chemotherapeutic treatment was initiated with a combined protocol of vincristine and doxorubicin. To the authors' knowledge, this is the first case report documenting the treatment of severe, refractory non-islet cell tumor-induced hypoglycemia in a dog, suspected to be secondary to an IGF-2 secreting nephroblastoma.

Patterns of nodal metastases, biological behaviour and prognosis of canine mast cell tumours of the pinna: A multi-institutional retrospective study.

Canine cutaneous mast cell tumours (cMCTs) of the pinna have been associated with an aggressive biological behaviour, although data remain scarce. The knowledge acquired over the past years on histologic gradings, and the value of lymph node (LN) staging, may help in better characterizing this anatomical presentation. The first aim was to describe the frequency, location, and histologic appearance of LN metastases in cMCT of the pinna. A second aim was to evaluate prognosis. Medical records of dogs with cMCT of the pinna, that underwent tumour and sentinel (SLN) or regional LN (RLN) excision, were reviewed. The influence of potential prognostic variables on time to progression (TTP) and tumour-specific survival (TSS) was investigated. Thirty-nine dogs were included: 19 (48.7%) had Kiupel high-grade (K-HG) and 20 (51.3%) had low-grade (K-LG) MCTs. Eighteen (46.1%) dogs underwent SLN mapping: the superficial cervical LN was at least one of SLN in 17 (94.4%) cases. Twenty-two (56.4%) dogs had LN metastases; the superficial cervical LN was always involved. On multivariable analysis, only K-HG was associated with increased risk of progression (p = .043) and tumour-related death (p = .021). Median TTP and TSS were 270 and 370 days in K-HG, respectively; these were not reached in dogs with K-LG tumours (p < .01). cMCTs of the pinna are often K-HG and are also associated with a higher frequency of LN metastasis; however, we confirmed the independent prognostic value of histologic grading. A multimodal treatment may lead to favourable long-term outcome. Moreover, the superficial cervical LN is most often the SLN.

The Role of Fine Needle Aspiration of Liver and Spleen in the Staging of Low-Grade Canine Cutaneous Mast Cell Tumor.

Clinical staging is a fundamental step in the clinical assessment of canine cutaneous mast cell tumor (cMCT), and it is recommended to evaluate the tumor draining lymph node (eTDLN), perform diagnostic imaging, and fine needle aspiration (FNA) of the spleen and liver to determine the presence of metastatic disease, thereby refining the prognosis. The aim of this retrospective study was to evaluate the prevalence of splenic and hepatic involvement in newly diagnosed canine low-grade cMCT (Patnaik grade I-II, Kiupel low-grade). Medical records of dogs that underwent a clinical staging work-up and surgical excision for a low-grade cMCT between December 2019 and December 2021 were reviewed at five veterinary centers. Only dogs with a histological diagnosis of low-grade cMCT, FNA or histology of the eTDLN, FNA of the spleen and liver, and one year of follow up were included. One hundred and thirty-six dogs met the inclusion criteria. Only 1 out of 136 dogs (0.7%) had the presence of visceral metastases at diagnosis, suggesting that the prevalence of visceral metastases in low-grade cMCT is extremely low. The results of this study are consistent with previous literature and suggest that after a diagnosis of low-grade cMCT, cytology of visceral organs may not represent an essential step in the clinical staging work-up.

Expression of cannabinoid receptors CB1 and CB2 in canine cutaneous mast cell tumours.

Cannabinoid receptors (CB1 and CB2) belong to endocannabinoid system (ECS), which is also composed from endocannabinoids and the enzymatic systems involved in their biosynthesis and degradation. The expression of CB1 and CB2 have been previously identified in normal canine mast cell and in atopic dermatitis. Canine cutaneous mast cell tumours (cMCTs) are among the most common cutaneous neoplasms in dogs and have a highly variable clinical behaviour. Expression of CB1-CB2 was assessed by means of immunohistochemistry in thirty-seven dogs (from 2019 to 2021) with proven histological diagnosis of cMCT. Dogs were divided in two groups according to the Kiupel's grading system: high-grade (HG) cMCT and low-grade (LG) cMCT. A semiquantitative (score 0-3) and quantitative assessment of immunoreactivity (IR) was performed for each case. Our results show that there CB1 and CB2 are highly expressed in LG- cMCT, in contrast to HG- cMCT.

Canine anal sac gland carcinoma with regional lymph node metastases treated with sacculectomy and lymphadenectomy: Outcome and possible prognostic factors.

The staging system commonly used in canine anal sac gland carcinoma (ASGC) is a revised Tumour-Node-Metastasis (TNM) system published in 2007. This staging system consists in four stages and, for dogs with nodal metastases, the size of the metastatic lymph node (mLN) defines the N stage. However, we hypothesise that (1) the mLN size has no prognostic significance when the mLN can be excised, (2) a high number of mLNs is associated with poorer prognosis and (3) the measurement of the mLN on imaging is not reproducible. To investigate these hypotheses, medical records and diagnostic images of dogs with ASGC and mLN, treated with sacculectomy and lymphadenectomy, with or without chemotherapy, were reviewed. Interobserver variability for mLN measurement was assessed. Prognostic factors including mLN size and number were investigated. Time to documented progression (TDP) and disease-specific survival (DSS) were evaluated. Progression-free interval (PFI) was analysed with interval-censored data analysis. Fifty-seven dogs were included. The median PFI, TDP and DSS were 110 (95%CI 61.5-185.5), 196 (95%CI 162-283) and 340 days (95%CI 321-471), respectively. For measurement of the largest mLN, interobserver agreement was excellent but limits of agreement reached 39.7%. Neither the size of the largest mLN nor the use of adjuvant chemotherapy were associated with outcome. The number of mLNs was associated with outcome and having more than four mLNs was associated with shorter PFI (p < .001), TDP (p = .004) and DSS (p < .001). While mLN size measurement was not consistently reproducible and did not influence outcome in our cohort, number of mLNs did. Further studies are required for development of a revised staging system.

Comparison between computed tomographic and ultrasonographic findings of the liver and spleen in dogs with confirmed hepatic or splenic lymphoma involvement.

BACKGROUND: Computed tomography (CT) and ultrasonography (US) may be used to assist staging in dogs with lymphoma. The imaging features of splenic and hepatic infiltration have never been directly compared in the same population of dogs. METHODS: The aim of this retrospective study was to describe and compare the CT and US findings of the liver and spleen in dogs with confirmed hepatic and/or splenic lymphoma and compare imaging and cytological diagnoses. RESULTS: CT and US studies of 18 dogs with multicentric lymphoma involving the liver and/or the spleen were retrospectively evaluated. US detected abnormalities more frequently than CT in the spleen with lymphoma, whereas CT detected abnormalities more frequently in the liver with lymphoma. The two diagnostic imaging modalities often disagreed in the findings, including the imaging classification of the organ as normal or abnormal. CONCLUSION: US and CT often disagree in the imaging findings present in hepatic and splenic lymphoma. The results of this study suggest that cytologic evaluation of both the liver and spleen is advisable regardless of their US or CT appearance for detection of lymphoma.

Ultrasound-guided placement of an anchor wire or injection of methylene blue to aid in the intraoperative localization and excision of peripheral lymph nodes in dogs and cats.

OBJECTIVE: To evaluate ultrasound-guided placement of an anchor wire (AW) or injection of methylene blue (MB) to aid in the intraoperative localization of peripheral lymph nodes in dogs and cats. ANIMALS: 125 dogs and 10 cats with a total of 171 lymphadenectomies. PROCEDURES: Medical records of dogs and cats that underwent peripheral lymphadenectomies with or without (N) the AW or MB localization technique were reviewed. Data retrieved included clinical, surgical, and histologic findings. The proportions of successful lymphadenectomies, lymph node characteristics, and complications among the 3 groups were analyzed. RESULTS: 143 (84%) lymph nodes were successfully excised. Lymphadenectomy success was significantly affected by the localization technique, with 94% for group AW, 87% for group MB, and 72% for group N. Lymph node size was smaller in groups AW and MB, compared with group N. Duration of lymphadenectomy was shorter in group AW, compared with groups MB and N, and in group MB, compared with group N. Intra- (7%) and postoperative (10%) complications and final diagnosis did not significantly differ among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Both lymph node localization techniques were highly successful and reduced surgery time, compared with unassisted lymphadenectomy. Specifically, these techniques were effective for localization of normal-sized and nonpalpable lymph nodes and were efficient and practical options for peripheral lymphadenectomies, particularly for those that were small or nonpalpable.

A retrospective study on prophylactic regional lymphadenectomy versus nodal observation only in the management of dogs with stage I, completely resected, low-grade cutaneous mast cell tumors.

BACKGROUND: While lymphadenectomy of metastatic lymph nodes (LNs) has been associated with improved outcome, the clinical utility of prophylactic lymphadenectomy in dogs with stage I cutaneous mast cell tumors (cMCTs) remains a controversial topic. To assess the therapeutic role of lymphadenectomy of uninvolved regional LNs, the long-term outcome of cMCT-bearing dogs with cytologically negative and surgically unresected regional LNs (observation only, OO) was compared with that of dogs with surgically resected and histologically negative regional LNs (prophylactic regional lymphadenectomy, PRL). RESULTS: A retrospective analysis of 64 dogs with a low-grade, completely resected stage I cMCT was performed: 35 (54.7%) dogs were subjected to OO and 29 (45.3%) underwent PRL. Dogs were monitored for a median of 813 and 763 days in the OO group and PRL group, respectively. The number of dogs undergoing MCT progression was significantly higher in the OO group (P = 0.028) and curve comparison revealed a tendency to a better time to progression in the PRL group (P = 0.058). No significant difference in survival time (P = 0.294) was observed between dogs in the OO and PRL groups. CONCLUSIONS: Our results showed that lack of immediate lymphadenectomy was associated with a higher risk for tumor progression. This preliminary judgement, reinforced by the findings that lymphadenectomy was well tolerated in all cases, and that histopathology provides the definitive assessment of the nodal pathological status, may suggest that prophylactic lymphadenectomy is indicated in the management of stage I MCTs. Larger prospective studies are warranted for generating clinical evidence of this latter hypothesis.

Timing of adjuvant chemotherapy after limb amputation and effect on outcome in dogs with appendicular osteosarcoma without distant metastases.

OBJECTIVE: To determine an optimal time interval between amputation and initiation of adjuvant chemotherapy (TIamp-chemo) in dogs with appendicular osteosarcoma without distant metastases and whether TIamp-chemo was associated with outcome. ANIMALS: 168 client-owned dogs treated at 9 veterinary oncology centers. PROCEDURES: Data were collected from the dogs' medical records concerning potential prognostic variables and outcomes. Dogs were grouped as to whether they received chemotherapy within 3, 5, 7, 10, 15, 20, 30, or > 30 days after amputation of the affected limb. Analyses were performed to identify variables associated with time to tumor progression and survival time after limb amputation and to determine an optimal TIamp-chemo. RESULTS: Median TIamp-chemo was 14 days (range, 1 to 210 days). Median time to tumor progression for dogs with a TIamp-chemo ≤ 5 days (375 days; 95% CI, 162 to 588 days) was significantly longer than that for dogs with a TIamp-chemo > 5 days (202 days; 95% CI, 146 to 257 days). Median overall survival time for dogs with a TIamp-chemo ≤ 5 days (445 days; 95% CI, 345 to 545 days) was significantly longer than that for dogs with a TIamp-chemo > 5 days (239 days; 95% CI, 186 to 291 days). CONCLUSIONS AND CLINICAL RELEVANCE: Findings indicated that early (within 5 days) initiation of adjuvant chemotherapy after limb amputation was associated with a significant and clinically relevant survival benefit for dogs with appendicular osteosarcoma without distant metastases. These results suggested that the timing of chemotherapy may be an important prognostic variable.

Clinical Features and Outcome of 79 Dogs With Digital Squamous Cell Carcinoma Undergoing Treatment: A SIONCOV Observational Study.

In dogs, digit squamous cell carcinoma (SCC) is uncommon. Clinical signs are frequently underestimated, leading to a diagnostic delay. The purpose of this retrospective study was to report our experience regarding the clinical presentation, diagnostic work-up, treatment and outcome of 79 client-owned dogs with SCC of the digit. The greatest majority (84.8%) of dogs was dark-coated. Schnauzers represented approximately one third of the study population, and had a poorer outcome compared with other breeds. The majority of SCCs occurred in the front limbs (61%), and bone lysis was frequently observed (92.4%). Approximately 9% of dogs had involvement of multiple digits, and this was associated with a shorter time to progression (TTP; P = 0.047). Similarly, a duration of clinical signs >90 days was associated with a shorter TTP (P = 0.02). Regional lymph node metastases were documented in 17.7% of dogs at admission and were significantly associated with tumor-related death (P < 0.001). At presentation, none of the dogs had evidence of distant metastasis. Digit amputation achieved adequate local tumor control in the majority of cases. Adjuvant chemotherapy and radiation therapy were carried out in 21.5% of cases, with uncertain benefit. Due to the relatively non-aggressive clinical behavior of digit SCC, chemotherapy should only be offered in the case of metastatic disease. Approximately one fourth of dogs developed de novo SCCs during the follow-up. Careful examination of the digits should be encouraged in breeds considered at high risk and in dogs with a previous history of digital SCC.

Immunohistochemical expression and prognostic significance of MAGE-A in canine oral malignant melanoma.

Canine oral malignant melanoma (COMM) is considered a chemo-resistant cancer with a poor long-term prognosis. The melanoma-associated antigen A (MAGE-A) genes, which belong to the cancer-testis antigen family, are expressed in several different canine cancers but not in normal somatic tissue. This study evaluates the expression of MAGE-A proteins and their prognostic role in COMM. The study was conducted in 2 parts. During the first part, biopsies from oral malignant melanomas from 43 dogs were examined and immunohistochemically assessed for expression of MAGE-A proteins. For the second part, the association between MAGE-A expression and outcome was assessed using follow-up data which was available for 20 dogs whose primary tumour had been controlled with surgery +/- radiation therapy. MAGE-A proteins were expressed in 88.4% (38/43) of oral malignant melanomas and had a predominantly cytoplasmic expression pattern. Immunopositivity was observed in more than 50% of the cells in 21 dogs (48.8%). Immunostaining intensity was classified as weak, moderate and intense in 16 (37%), 16 (37%) and 6 (14%) cases, respectively. No staining for MAGE-A was seen in 5 dogs (11%). Dogs whose COMM had weak MAGE-A staining intensity had a median survival time (MST) of 320 days while this was 129 days for dogs with moderate and intense immunostaining (p = 0.161). Dogs whose COMM had >50% of positive staining neoplastic cells had an MST of 141 days and dogs with a staining <50% had an MST of 320 days (p = 0.164). MAGE-A expression did not influence survival in our cohort.

Correlation between Tumour Associated Macrophage (TAM) Infiltration and Mitotic Activity in Canine Soft Tissue Sarcomas.

Tumour-associated macrophages (TAMs) are an important part of the tumour microenvironment but knowledge of their distribution in canine soft tissue sarcomas (STSs) is limited to absent. We analysed 38 STSs retrieved from the veterinary pathology archive; oral and visceral STSs, synovial cell sarcoma, tumours of histiocytic origin, haemangiosarcoma, carcinosarcomas, and undifferentiated tumours were excluded. Iba-1 positive, non-neoplastic tumour infiltrating cells (morphologically indicative of macrophages) were classified as TAMs and were counted in 10 consecutive tumours areas, where no necrosis or other inflammatory cells could be identified. Associations between numbers of TAMs and mitoses, differentiation, and necrosis scores or grade were investigated. TAMs were evident in all STSs and ranged between 6% to 62% of the cells in the microscopic field. The number of TAMs positively correlated with the STSs' histologic grade. When the components of the grade were analysed separately, TAMs were statistically correlated with mitoses, but not with differentiation or necrosis score. The present findings suggest that TAMs are present in higher numbers when STS proliferation is the predominant feature that drives tumour grade. The abundant presence of TAMs in high-grade STSs may also increase the likelihood of a pathologist misdiagnosing STS for histiocytic sarcoma.

Clinical, CT, and ultrasonographic features of canine and feline pleural and peritoneal carcinomatosis and sarcomatosis.

Carcinomatosis and sarcomatosis describe the widespread dissemination of metastatic neoplastic cells throughout the body. Studies describing their clinical and imaging features in veterinary patients are limited. The objective of this retrospective, multicenter, cross-sectional study is to describe the clinical, ultrasonographic, and CT features of pleural and peritoneal carcinomatosis and sarcomatosis in dogs and cats to aid detection and differentiation of these lesions. Medical records and CT and ultrasonographic images were reviewed. Although a large degree of overlap was observed between the imaging features and clinical signs of canine and feline carcinomatosis and sarcomatosis, some distinguishing features were observed. Dogs were significantly more likely to present with abdominal pain compared to cats (P = .022), whereas cats more commonly presented with inappetence (P = .019). Dogs with sarcomatosis had a significantly heavier bodyweight than dogs with carcinomatosis (P = .005), largely due to a higher prevalence of splenic hemangiosarcoma in this patient cohort. Peritoneal effusion was more frequently observed in dogs with carcinomatosis compared to dogs with sarcomatosis (P = .021). Imaging and clinical features observed in this study may help to distinguish sarcomatosis and carcinomatosis lesions. Due to the large degree of overlap observed, cytological or histopathological analysis is recommended for definitive diagnosis.

Ultrasound-Guided Hook-Wire Localization for Surgical Excision of Non-Palpable Superficial Inguinal Lymph Nodes in Dogs: A Pilot Study.

The evaluation of loco-regional lymph nodes (LN) plays an important prognostic role and assists the clinical decision making in canine cancer patients. Excision of non-palpable LN can be challenging. The aim of the study was to evaluate surgical time, successful excision rate and surgical complications associated with the use of an ultrasound-guided hook-wire (UGHW) LN localization method for non-palpable superficial inguinal LN (SILN) in dogs. Dogs that presented for excision of non-palpable SILN, performed with the aid of an UGHW placement, were enrolled. Information including signalment, SILN width, UGHW placement and surgical procedure time, hook-wire position, successful excision and intra- and post-operative complications were reviewed. Seventeen dogs were enrolled. Median LN width was 3 mm (range 2-11). Median time of preoperative UGHW placement and surgical LN excision was 8 min and 15 min, respectively. Successful SILN excision was achieved in all cases. Two minor intra-operative (hook migration and wire fragmentation) and one minor post-operative complications (seroma) were observed. No major intraoperative or post-operative complications occurred. The UGHW LN localization method is safe and effective and may allow a high rate of successful SILN excisions in dogs. This method has the potential to facilitate LN excision for other superficial LN locations.

Cranial solitary osseous plasmacytoma and subjacent amyloid deposition in a dog.

Solitary osseous plasmacytomas affecting the vertebrae, the zygomatic arch, and ribs occur in dogs. In this report, we describe clinical and imaging features of a solitary osseous plasmacytoma affecting the skull with deposition of amyloid forming a mass-like lesion. To the authors' knowledge, no similar cases have been reported before.

An open-label dose escalation study evaluating tolerability and safety of a single 5-days course of temozolomide in dogs with advanced cancer.

Temozolomide is a novel oral alkylating agent that has schedule-dependent clinical activity in human malignant glioma and metastatic melanoma. Little is known about the efficacy of temozolomide in the treatment of canine solid cancers, where broad range of dosages have been used but no maximally tolerated dose (MTD) had been established. The aim of this this open-label, dose-escalating study was to determine MTD and dose-limiting toxicity (DLT) of a single temozolomide cycle in dogs with advanced solid tumours. Temozolomide was administered as a 5-days course starting at 70 mg/m2 , using escalation of 10 mg/m2 increments with 3 dogs per dose level. MTD was established based on the number of dogs experiencing DLT assessed after 1 cycle. Safety evaluation was performed 10 days after dosing. Thirty-three client-owned dogs were enrolled. MTD was established at 150 mg/m2 and the most frequent adverse events (AEs) were hematologic and hepatic, followed by gastrointestinal, with the majority being self-resolving and of mild grade. VCOG grade 3 hepatic toxicity and grade 4 thrombocytopenia were defined as DLTs at 160 mg/m2 . A subcohort of dogs received multiple temozolomide doses on a 4-week cycle and no cumulative toxicity was documented. Conclusions of this study define temozolomide MTD at 150 mg/m2 when given once daily over 5 days. Future trials on the efficacy of temozolomide administered at its MTD are warranted.