Oertzenweg 19 b
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Soft-tissue sarcomas are a group of tumors that exhibit similar clinical behavior, namely, local invasiveness, a low metastatic rate, and frequent return following conservative excision. Histotypes such as fibrosarcoma (FSA), hemangiopericytoma (HPC), malignant fibrous histiocytoma, and malignant peripheral nerve sheath tumors (MPNST) are included in the soft-tissue sarcoma family. Seventy dogs were treated with radiation at Veterinary Oncology Services (Edmonds WA, USA) for soft-tissue sarcomas between the years 1995-2001 were retrospectively reviewed. Sixty-six dogs were treated with a definitive radiation protocol (29-52.5 Gy, 14-15x3.5 Gy) and six dogs were treated received a palliative protocol (24-32 Gy, 3-4x8 Gy) as a lone radiation modality. Each dog was placed into one of four groups to examine factors that possibly influence disease-free interval and survival as well as to allow for a more exact characterization of the clinical course of disease. Group I consisted of 50 dogs that were treated with a definitive radiation protocol for 51 incompletely resected non-oral soft tissue sarcomas. Sixteen HPC, 17 FSA 9 MPNST and 15 tumors that were too rare to constitute independent groups were collectively analyzed as "Misc" tumors were represented in Group I. Seven recurrences were noted in Group I, 5 of those were of the MPNST Histotype. The median disease free interval was estimated to be 1629 days for dogs in Group I. Group II consisted of fourteen dogs that were treated for with a definitive radiation protocol for oral sarcoma. Nine dogs were treated following incomplete resection; 5 dogs were treated for measurable disease. Median disease free interval was estimated to be 513 days. Median disease-free interval was longer for dogs treated for resected disease (1572 days) than for dogs that were treated for macroscopic disease (226 days). Group III was composed of 3 dogs that received a definitive protocol that were treated with a definitive radiation protocol for inoperable sarcoma. All three tumors exceeded 10cm in diameter. One dog with an infiltrative lipoma experienced long term tumor stabilization. Six dogs that received a hypofractionated protocol a sole treatment modality were placed into Group IV. Five of 6 dogs were treated with palliative intent; one dog was treated with a hypofractionated protocol due to co-morbidity that precluded a more definitive protocol. Of the 5 dogs that were palliative treated. A reduction in tumor-associated symptoms was observed in 4 of 5 dogs. Recurrence was shown to be prognostic for shortened survival as was oral local and tumors not amenable to resection. Radiation treatment in combination with conservative surgery presents a promising alternative to ablative surgery. Radiation therapy may also offer benefit in cases were surgical excision is not possible.