Objective—To evaluate and compare the outcomes of dogs with periarticular histiocytic sarcoma (PAHS) and histiocytic sarcoma of other anatomic locations (non-PAHS) and identify factors associated with outcome for dogs with PAHS.
Design—Retrospective cohort study.
Animals—19 dogs with PAHS and 31 dogs with non-PAHS.
Procedures—Medical records of dogs with histiocytic sarcoma that underwent definitive local treatment (surgery or radiation), chemotherapy, or a combination of these were reviewed. Patient signalment, clinical signs, staging test results, clinicopathologic data, type of treatment, response, and outcome were collected, and potential risk factors in dogs with PAHS were identified and analyzed for an association with outcome.
Results—Dogs with PAHS lived significantly longer than did dogs with non-PAHS, with an overall median survival times of 391 (range, 48 to 980) and 128 (range, 14 to 918) days, respectively, despite the presence of suspected metastasis at diagnosis in 13 of 19 dogs with PAHS. Dogs with PAHS without evidence of metastasis at diagnosis lived significantly longer than did dogs with PAHS with evidence of metastasis, with median survival times of 980 (range, 83 to 980) and 253 (range, 48 to 441) days, respectively. Administration of prednisone in dogs with PAHS was associated with a significantly shorter time to tumor progression (TTP) and increased risk of tumor progression and death.
Conclusions and Clinical Relevance—Results indicated that dogs with PAHS may have a favorable outcome independent of metastatic status when treated with chemotherapy or aggressive multimodal treatment. The concurrent administration of prednisone may be a negative predictive factor for survival time and TTP in dogs with PAHS.
Objective—To evaluate the usefulness of carboxyterminal cross-linked telopeptide of type I collagen (ICTP) concentrations for screening dogs for the presence of osteosarcoma.
Sample Population—32 client-owned dogs with osteosarcoma (27 dogs with osteosarcoma of the appendicular skeleton and 5 dogs with osteosarcoma of the axial skeleton) and 44 non–tumor-bearing control dogs.
Procedures—Serum was obtained from blood samples collected from dogs with osteosarcoma and from clinically normal dogs. The serum ICTP concentration was determined by use of a commercially available radioimmunoassay for ICTP.
Results—Mean ± SD serum ICTP concentration in the tumor-bearing dogs was 7.32 ± 2.88 ng/mL, and in clinically normal dogs, it was 6.77 ± 2.31 ng/mL; values did not differ significantly. Mean serum ICTP concentration in dogs with appendicular osteosarcoma, compared with that of clinically normal dogs, was not significantly different. Mean serum ICTP concentration in dogs with axial skeletal tumor location was 10.82 ± 2.31 ng/mL, compared with a value of 6.73 ± 2.28 ng/mL in dogs with appendicular osteosarcoma.
Conclusions and Clinical Relevance—On the basis of the results of this study, serum ICTP concentrations are not a clinically useful screening tool for the detection of appendicular osteosarcoma in dogs. Despite the observation that serum ICTP concentration was higher in dogs with axial osteosarcoma than in clinically normal dogs, serum ICTP concentration determination is not a suitable screening test for osteosarcoma.
Objective—To compare results of treatment with temozolomide or dacarbazine, in combination with an anthracycline, in dogs with relapsed or refractory lymphoma.
Design—Nonrandomized, controlled clinical trial.
Animals—63 dogs with relapsed or refractory lymphoma.
Procedures—Chemotherapy was administered in 21-day cycles. A combination of temozolomide and an anthracycline (doxorubicin or dactinomycin) was administered to 21 dogs and a combination of dacarbazine and an anthracycline was administered to 42 dogs. Efficacy and toxicoses were assessed.
Results—Thirteen of the 18 (72%) dogs treated with the temozolomide-anthracycline combination and 25 of the 35 (71%) dogs treated with the dacarbazine-anthracycline combination had a complete or partial response. Median duration of response to rescue chemotherapy was 40 days (range, 0 to 217 days) for dogs in the temozolomide group and 50 days (range, 0 to 587 days) for dogs in the dacarbazine group. The incidence of high-grade hematologic toxicoses was significantly higher among dogs in the dacarbazine group than among dogs in the temozolomide group, but the incidence of gastrointestinal tract toxicoses was not significantly different between groups. There were no significant differences between groups in regard to proportion of dogs with a complete or partial response, duration of response to rescue chemotherapy, survival time following rescue chemotherapy, or overall survival time.
Conclusions and Clinical Relevance—Both combinations had promise in the treatment of dogs with relapsed or refractory lymphoma, although administration of temozolomide was more convenient than administration of dacarbazine and caused fewer hematologic toxicoses.