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.

Canine soft tissue sarcoma managed in first opinion practice: outcome in 350 cases.

OBJECTIVE: To determine outcome of dogs with a diagnosis of soft tissue sarcoma managed in first opinion practice. STUDY DESIGN: Retrospective, case-controlled study ANIMALS: Dogs (n = 350) with primary occurrence of a soft tissue sarcoma. METHODS: A previously validated questionnaire was sent to all veterinarians requesting clinical information and ultimate outcome for all dogs. Histologic sections were reviewed by a single pathologist. RESULTS: Most surgeries were unplanned, with only 15 (4%) dogs having a histologic and 59 (16.8%) dogs having a cytologic diagnosis before surgery. Median survival time for all dogs was not reached with 70% proportional survival at 5 years. Local recurrence developed in 73 (20.8%) cases. The extent of resection performed was not associated with improved survival (P = .2) or tumor recurrence (P = .8). Age <8 years (χ(2) = 6.1; P = .01), tumors <5 cm in size (χ(2) = 9.6; P = .002) and discrete tumors (χ(2) = 16.6; P < .001) had improved survival outcomes. On multivariate analysis, a high tumor grade was significant for recurrence (HR 5.8; P < .001; 95% CI: 2.2-14.8). Evidence of a selection bias towards less aggressive tumors being managed in first opinion practice was confirmed. CONCLUSIONS: Wide resection margins are not the primary determinant of outcome for all soft tissue sarcoma. Veterinarians need to better understand the biologic behavior of a suspected soft tissue sarcoma before treatment to allow surgical margins to be adjusted accordingly.

Vincristine overdose in a cat: clinical management, use of calcium folinate, and pathological lesions.

A 6-year-old female neutered Burmese cat received a 10 times overdose (5mg/m(2)) of vincristine, administered in error. Supportive therapy, including administration of calcium folinate, was instigated within 8h. Despite treatment, the patient exhibited deterioration in renal and respiratory function and died 72 h after overdose. Necropsy was performed within 24h of death. Gross examination revealed pulmonary oedema and a pale brown liver with a prominent lobular pattern. Histological examination revealed marked apoptosis and necrosis of the bone marrow myeloid series, and mild to moderate apoptosis and necrosis of the erythroid and megakaryocyte series. Multifocal necrosis of the renal tubules, hepatocytes, and small intestinal crypt epithelium was also observed. Use of calcium folinate as a rescue therapy following vincristine overdose in humans has been previously documented. If treatment is to be successful in cases of vincristine overdose in cats, then a more complete understanding of the pathogenesis of vincristine toxicity in companion animal species is required.

Pulmonary oedema as a suspected adverse drug reaction following vincristine administration to a cat: a case report.

This report describes recurrent respiratory distress following vincristine administration to a cat with chronic lymphocytic leukaemia. The cat was treated with a combination of vincristine, chlorambucil and prednisolone with initial success. After approximately 4 months, dyspnoea developed within 6 h of vincristine administration. Emergency therapy was instituted resulting in a full recovery. Further vincristine was administered; dyspnoea was similarly noted after all but one of these treatments. Dyspnoeic episodes were not attributable to alterations in vincristine dose or method of administration. The repeated temporal association was consistent with a suspected adverse drug reaction to vincristine.

Clinical stage, therapy, and prognosis in canine anal sac gland carcinoma.

BACKGROUND: Reports of canine anal sac gland carcinoma (ASGC) describe varied clinical presentations and management and differing responses to therapy. A unifying approach to clinical stage determination and management of this disease has yet to be presented. HYPOTHESIS: An ordinal clinical staging scheme for canine ASGC can be devised on the basis of responses to therapy for a retrospective cohort of affected dogs. ANIMALS: 130 dogs with naturally occurring ASGC. METHODS: A simplified clinical stage system and a management algorithm for canine ASGC were derived from retrospective evaluation of a cohort of 80 dogs; applicability of both was then prospectively evaluated in a cohort of 50 dogs. RESULTS: Retrospective evaluation revealed 4 statistically significant negative prognostic indicators for survival: lack of therapy, presence of distant metastases, presence of lymph node metastases, and primary tumor size. Lymph node extirpation was a statistically significant positive prognostic indicator by bivariate analysis. In both retrospective and prospective analyses, the modified clinical stage scheme revealed a significant association with survival time. CONCLUSIONS AND CLINICAL IMPORTANCE: The clinical staging scheme permits differentiation between groups in terms of prognosis and, therefore, decisions on therapy. This will facilitate application of appropriate therapy and enhanced communication and collaboration in further investigations of ASGC.

Solitary plasmacytoma of bone in two successfully treated cats.

This is the first report of feline solitary plasmacytoma of bone. We describe the clinical, clinico-pathological, radiographic and pathological findings of two successfully treated cats with long-term follow-up. The first case presented with spinal pain and neurological deficits. Radiographs demonstrated sclerosis of lumbar vertebra L6 and a myelogram confirmed interference to flow of contrast in the L4-7 region. A biopsy of L6 revealed neoplastic plasma cell infiltration. There was no evidence of paraproteinaemia on serum protein electrophoresis. The cat underwent hypofractionated megavoltage radiotherapy. Clinical signs resolved completely and 4 years after diagnosis the cat remains well and has no electrophoretically detectable paraproteinaemia. The second case presented with neurological deficits of the tail and spinal radiographs revealed extensive osteolysis of the sacrum. A biopsy of sacral bone demonstrated neoplastic plasma cell infiltration. The animal was normoglobulinaemic. The cat improved clinically with induction chemotherapy (melphalan and methylprednisolone). The same chemotherapeutics were continued at maintenance doses for 4.3 years, at which time there was recurrence of neurological deficits and a palpable sacral mass. Cytological examination of a fine needle aspirate confirmed recurrence of plasma cell neoplasia. A low concentration monoclonal paraproteinaemia was detected. Vincristine was administered resulting in resolution of neurological deficits and a palpably smaller sacral mass. Eighteen months into vincristine therapy, there was recurrence of clinical signs and the cat was euthanased, more than 6 years after the initial diagnosis.

Myeloma-related disorders in cats commonly present as extramedullary neoplasms in contrast to myeloma in human patients: 24 cases with clinical follow-up.

BACKGROUND: Myeloma-related disorders (MRD) are rare neoplasms of plasma cells. Published case reports describe a diversity of clinical presentations with confusing terminology and diagnostic criteria as a consequence of the assumption that MRD in cats are analogous to those in dogs or humans. OBJECTIVE: The aim of the study was to describe clinical, clinicopathologic and imaging findings, response to treatment, survival and possible associations with other diseases or vaccination in a large case series. A priori hypotheses were that cats with MRD commonly present with extramedullary involvement and uncommonly have radiographic bone lesions, in contrast to human patients. ANIMALS: Twenty-four cats with MRD confirmed by cytology or histopathology and immunohistochemistry. METHOD: A multicenter retrospective study was performed. RESULTS: Two types of clinical presentation were observed. The first group (n = 17) had neoplasia involving abdominal organs, bone marrow, or both. All developed systemic clinical signs and paraproteinemia. Five of 7 cats that received chemotherapy improved clinically or had decreased serum globulin concentration (median survival, 12.3 months; range, 8.5-22 months). The second group comprised 7 cats with skin masses, 2 of which were paraproteinemic and developed rapidly worsening systemic signs. In cats without systemic signs, excision of the skin masses appeared to be associated with prolonged survival (up to 2.4 years). Cats with MRD commonly presented with extramedullary involvement (67%), versus humans with MRD (5%) (P < .001), and uncommonly presented with radiographic bone lesions (8%) versus humans with MRD (80%) (P < .001). CONCLUSIONS: Radiographic bone lesions are uncommon in cats with MRD and extramedullary presentation is common, relative to human myeloma.