Stephen J. Withrow

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Pulmonary metastasis continues to be the most common cause of death in osteosarcoma. Indeed, the 5-year survival for newly diagnosed osteosarcoma patients has not significantly changed in over 20 years. Further understanding of the mechanisms of metastasis and resistance for this aggressive pediatric cancer is necessary. Pet dogs naturally develop(More)
Childhood osteogenic sarcoma (OS) is a rare bone cancer occurring primarily in adolescents. The North American pediatric cooperative groups have performed a series of clinical treatment trials in this disease over the past several decades, and biology studies of tumor tissue have been an important study component. A meeting was held in Bethesda, Maryland on(More)
Thirty-nine, older, large-breed dogs with multilobular osteochondrosarcoma (MLO) each presented primarily with a fixed mass involving the flat bones of the skull. Twenty-five dogs were treated with surgical resection alone, nine were treated with adjuvant therapy, and five were not treated. Forty-seven percent of dogs treated had local tumor recurrence, and(More)
One hundred and fifteen dogs with neoplasms of the lower urinary tract (bladder and/or urethra) were retrospectively evaluated at five referral institutions participating in ongoing studies by the Veterinary Cooperative Oncology Group. Most tumors were malignant (97%) and of epithelial origin (97%). Lower urinary tract tumors were more common in older dogs(More)
Fifty dogs with pheochromocytoma were identified in a retrospective study of a 9-year period. For 24 of 50 dogs (48%), the tumor was an incidental finding during necropsy or surgery. Presenting signs were referrable to the nervous system in 7 of the 26 symptomatic dogs (27%); were referrable to the cardiopulmonary system in 7 of 26 dogs (27%); or were(More)
Forty-eight dogs with histologically confirmed appendicular osteosarcoma (OSA) entered a prospective clinical trial evaluating treatment with amputation and up to 4 doses of carboplatin given every 21 days. The median disease-free interval (DFI) was 257 days, with 31.2% of the dogs disease-free at 1 year. The median survival time was 321 days, with 35.4% of(More)
Of 82 dogs with thyroid carcinoma seen between January 1981 and October 1989, 20 had freely movable tumors without evidence of metastasis and were treated with surgical excision alone. Uncensored mean and median survival times for these 20 dogs were both 20.5 months. Kaplan-Meier survival analysis, which censors for nontumor-related deaths and dogs lost to(More)
OBJECTIVE To determine results of surgery for treatment of soft-tissue sarcomas in dogs and to identify prognostic variables that can be used to predict outcome. DESIGN Retrospective case series. ANIMALS Dogs with soft-tissue sarcomas that had surgical treatment only. PROCEDURE Records were examined for clinically relevant data. Histologic samples(More)
The medical records of 12 dogs with multilobular osteochondrosarcoma (MLO) and examined at the Veterinary Teaching Hospital, Colorado State University from August 1979 to January 1987 were reviewed. Medical records of 1 dog with MLO and 3 dogs with MLO examined at the Ontario Veterinary College, University of Guelph and the Veterinary Medical Teaching(More)
Medical records of 23 dogs in which thymoma was diagnosed between Jan 1, 1980 and Dec 31, 1991 were reviewed. All thymomas were located in the cranial mediastinum. Eleven dogs had megaesophagus, and myasthenia gravis was confirmed in 7 of these 11. One dog developed clinical signs of myasthenia gravis after removal of the thymoma. Concurrent, nonthymic(More)