Evaluation of zoledronate for the treatment of canine stage III osteosarcoma: A phase II study.

BACKGROUND: Greater than 90% of dogs with appendicular osteosarcoma will develop pulmonary metastasis despite the standard of care. Available treatments have limited efficacy for stage III disease. Zoledronate, a bisphosphonate, induces apoptosis of canine osteosarcoma cells and appears to modulate the tumour microenvironment. OBJECTIVES: This prospective, single institutional phase IIa trial investigated the use of single agent zoledronate in dogs with pulmonary metastases from osteosarcoma. METHODS: Zoledronate was administered once monthly, and thoracic radiographs were used to assess response. RESULTS: Eleven dogs were enrolled. Stable disease was achieved in two of eight dogs available for response assessment. The median progression-free survival was 28 days (range: 4-93 days). The median stage III-specific survival time was 92 days. Adverse events were reported in four dogs; two dogs developed grade III or higher toxicities. Notable adverse events included conjunctivitis, fever, hypocalcaemia, and hypophosphatemia. CONCLUSIONS: Zoledronate appears to have limited efficacy as a single agent for stage III osteosarcoma and may be associated with unexpected toxicity in this population. This clinical trial was registered on the AVMA Animal Health Studies Database (AAHSD004396).

Bacterial infection in dogs with aspiration pneumonia at 2 tertiary referral practices.

BACKGROUND: In dogs, antimicrobial drugs are widely prescribed for aspiration pneumonia (AP) despite poor documentation of bacterial infection in AP (b-AP) using bronchoalveolar lavage fluid (BALF) analysis. Interpretating discordant cytology and culture results is challenging, contributing to lack of a criterion standard, and highlighting differences between veterinary and human medical criteria for b-AP. OBJECTIVES: Determine how many dogs with AP had BALF collection and differences in diagnosis of b-AP using veterinary vs human medical criteria. Report findings of noninvasive markers (e.g. fever, band neutrophilia, radiographic severity score) in dogs with and without b-AP. ANIMALS: Retrospective cohort study of client-owned dogs (n = 429) with AP at 2 university veterinary hospitals. Twenty-four dogs met enrollment criteria. METHODS: Inclusion criteria were radiographic diagnosis of AP, ≥1 risk factor, CBC findings, and BALF cytology and culture results. Veterinary medical b-AP criteria were cytology findings compatible with sepsis with or without positive culture, or cytology findings not consistent with sepsis and positive culture (≥1.7 × 103  cfu/mL). Human medical b-AP criteria required culture with ≥104  cfu/mL or > 7% cells with intracellular bacteria on cytology. RESULTS: Only 24/429 dogs met all enrollment criteria; 379/429 dogs lacked BALF collection. Diagnosis of b-AP differed using veterinary (79%) vs human (29%) medical criteria. Fever, band neutrophils and high radiographic scores were noted in dogs with and without b-AP. CONCLUSIONS AND CLINICAL IMPORTANCE: Lack of routine BALF collection hampers definitive recognition of bacterial infection in AP. Differences in dogs meeting veterinary vs human medical definitions for b-AP and usefulness of noninvasive markers warrant further study to improve understanding of the role of bacteria in AP.

Sentinel lymph node detection differs when comparing lymphoscintigraphy to lymphography using water soluble iodinated contrast medium and digital radiography in dogs.

Sentinel lymph node (SLN) mapping by various means has become standard of care in certain types of human cancers and is receiving more attention in veterinary oncology. Current SLN mapping techniques can be costly and often require advanced imaging equipment. The objective of this prospective, method comparison study was to compare an SLN mapping protocol of lymphoscintigraphy to lymphography using water soluble iodinated contrast medium (WIC) and digital radiography for identification of an SLN. Lymphoscintigraphy and lymphography were performed on eight healthy purpose-bred dogs using technetium-99m sulfur colloid and WIC injected into the subcutaneous tissues in a four-quadrant technique around a predefined area of skin on the brachium. Images were obtained using a gamma camera and digital radiography at different time points post-injection. Image sequences were evaluated by one of two American College of Veterinary Radiology board-certified veterinary radiologists. Data obtained were compared between methods using descriptive statistics. An SLN was identified in all dogs with lymphoscintigraphy and seven of eight dogs with lymphography. Agreement between results of the lymphoscintigraphy and lymphography studies was a complete match in three dogs, a partial match in four dogs, and no match in one dog. The SLN detected differed based on the imaging modality used.

The effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium in a simulated tumor model.

OBJECTIVE: To determine the effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium. STUDY DESIGN: Experimental study. ANIMALS: Eight healthy research beagles. METHODS: A predefined area of skin measuring 2 × 1.5 cm in dimension was designated on either the right or left brachium. Preoperative lymphoscintigraphy was performed with technetium sulfur colloid injected into the subcutaneous tissues around the predefined anatomic location in a four-quadrant technique. Dogs underwent surgery for excision of the predefined area of skin, subcutis, and fascia of the lateral head of the triceps muscle with 1-cm margins. Eighteen days after surgery, lymphoscintigraphy was again performed with technetium sulfur colloid injected into the subcutaneous tissues around the surgical scar in a four-quadrant technique. RESULTS: Sentinel lymph nodes were identified in eight of eight dogs preoperatively and in eight of eight dogs postoperatively. Agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was identified as complete in four of eight dogs and partial in four of eight dogs. Sentinel lymph node identification occurred immediately in three of eight dogs preoperatively and in eight of eight dogs postoperatively. CONCLUSION: Sentinel lymph node identification occurred faster postoperatively. Agreement or partial agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was observed in eight of eight dogs. CLINICAL SIGNIFICANCE: Surgery appears to have an effect on lymphoscintigraphy drainage patterns. Additional studies are required to compare preoperative and postoperative sentinel lymph node mapping patterns in tumor-bearing dogs. However, this study provides preliminary information regarding the effect of surgery on sentinel lymph node identification.