![paws_banner.png]()
+ General Considerations
- Axial OSA comprises 25% of all OSA cases and 59% in dogs < 15 kg
- Breed predisposition: ± Boxer
- Sex predisposition: female with a male-to-female ratio of 1:2.1 in all sites except ribs and vertebrae
- OSA sites in the axial skeleton include:
- Rib (10%-11% of axial OSA and 6.2% of all OSA cases)
- Vertebrae (15%-16% of axial OSA and 3.2% of all OSA cases)
- Mandible (27% of axial OSA and 3.2% of all OSA cases)
- Maxilla (16%-22% of axial OSA and 3.2% of all OSA cases)
- Scapula (2.4%-13% of axial OSA)
- Skull (10%-54% of axial OSA and 2.3% of all OSA cases)
- Nasal cavity or paranasal sinuses (9% of axial OSA)
- Pelvis (4%-6% of axial OSA)
- Behaviour of axial OSA is less aggressive
- Tumor-free surgical margins are difficult with axial OSA due to location
- Local tumor recurrence (80%) is more common cause of death than distant metastasis (7.4%)
- Metastatic potential is lower in axial OSA v appendicular OSA
- 11%-18% metastatic rate in dogs with axial OSA at diagnosis and 35%-46% at necropsy
- 27%-45% metastatic rate for rib OSA
- 17% metastatic rate for skull OSA
- Metastatic rate is higher with rib and scapula OSA
- Metastatic rate is lower with mandibular and maxillary OSA
- Metastatic rate is higher telangiectatic OSA and telangiectatic OSA are usually large and incompletely resected
+ Prognosis
- MST 120-154 days, with a 12-month survival rate 26.3% and 24 month survival rate 18.4%
- Chemotherapy does not influence metastasis or survival
- Prognostic factors: breed, body weight (small), anatomic site (mandible), body weight (small), treatment option, and completeness of surgical excision
- MST is significantly decreased in Golden Retrievers with axial OSA (100 days v 182 days in pure bred dogs and 264 days in other dogs)
- MST is significantly decreased in dogs treated with palliative rather than curative-intent radiation therapy (79 days v 265 days)
