The results of this retrospective study indicate that many spindle cell tumours managed in first opinion practice exhibit a low-grade biological behaviour and may respond well to more conservative surgery than current recommendations advise.
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 (χ2 = 6.1; P = .01), tumors <5 cm in size (χ2 = 9.6; P = .002) and discrete tumors (χ2 = 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.
In the second of a two-part article on the canine intervertebral disk, the morphological changes which occur within the disk during aging and degeneration are described. Degeneration of the intervertebral disk appears to be a self-perpetuating process as a consequence of disruption to the annulus fibrosus, cellular remodeling, altered biomechanical loading, and nutritional deficiencies. In the nonchondrodystrophoid disk, premature acceleration of the aging process can occur following traumatic disruption to the annulus fibrosus. This degeneration usually occurs in isolated disks along the length of the vertebral column. By contrast, disk degeneration in the chondrodystrophoid breeds occurs simultaneously in all disks along the vertebral column and usually is well advanced by two years of age. Ultrastructural differences between the intervertebral disk of the nonchondrodystrophoid dog and that of the chondrodystrophoid dog may explain the rapidity and severity of degenerative changes in the latter breeds.
Soft tissue sarcomas are derived from tissues of mesenchymal origin. Although local recurrence following surgical resection is the characteristic challenge in their management, 40% dogs with high‐grade tumours may also develop metastatic disease, despite successful local control. Soft tissue sarcoma is a complex disease and there are many uncertainties regarding the biology and optimal clinical management. There are currently no diagnostic tests that can reliably predict the amount of surgical margin required for a particular tumour, so there can be a mismatch between treatment and disease. Historically, the tendency has been to always recommend wide excision margins but this is not fully supported by recent evidence. A selection bias for less aggressive soft tissue sarcomas in primary care practice can account for good outcomes that are achieved despite narrow surgical excision margins. On the other hand, inappropriately conservative treatment will adversely affect outcomes for patients with more aggressive disease. This review provides an update on the current understanding of management of canine soft tissue sarcomas.
Intervertebral disk disease continues to be a common and debilitating condition of dogs. In the first of a two-part article on the canine intervertebral disk, the microscopic and ultrastructural anatomy of the normal, nonchondrodystrophoid disk is described. Specific attention is placed on elements of the structure which impart important functional attributes. Finally, the role of the intervertebral disk in providing flexibility to the vertebral column is discussed, with a description of its biomechanical properties and reaction to compressive loads.
Survival times for most tumor types can be good, but surgical margins should be carefully evaluated to ensure complete tumor removal. Adjuvant therapies may be advisable particularly for dogs to reduce rates of local recurrence or distant metastasis.
This study assesses the outcome of two combined treatment strategies for the treatment of feline injection-site sarcoma (FISS). Twenty-one cats with primary or recurrent FISS received 3 cycles of neoadjuvant chemotherapy with epirubicin (25 mg m(-2) ), then an anatomical resection of the entire muscle compartment containing the tumour was performed based on the findings of co-axial imaging. Cats then received a further 3 cycles of adjuvant chemotherapy. Follow-up was performed by telephone contact with a median follow-up time of 1072 days. Three cats (14%) developed local tumour recurrence at days 264, 664 and 1573 after surgery. A median survival time could not be calculated as over 80% of the study population remained alive or were censored due to death from other causes. When compared to historical controls, the results of this study demonstrate superior rates of tumour-free survival and disease-free interval.
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