Oncology
Core concepts
Oncology questions emphasize diagnosis, staging, and therapeutic decision-making. Know the difference between benign and malignant behavior, the value of cytology (fine-needle aspirate) vs. biopsy/histopathology, and the principles of staging (regional lymph node, thoracic imaging, abdominal imaging). Familiarize yourself with common tumors: canine lymphoma (multicentric, immunophenotype matters, CHOP-based protocols), mast cell tumor (grading, c-kit mutation, role of tyrosine kinase inhibitors), osteosarcoma (appendicular, amputation plus chemotherapy), hemangiosarcoma (splenic, poor prognosis), and transitional cell carcinoma (bladder, COX inhibitors). Understand paraneoplastic syndromes (hypercalcemia of malignancy, hypoglycemia, hypergammaglobulinemia) and the concept of tumor grade vs. stage. Recognize when palliative care is appropriate.
Common traps
- Treating without a diagnosis-always confirm with cytology or histopathology when feasible.
- Confusing grade (differentiation) with stage (extent).
- Forgetting to stage before committing to definitive local therapy.
- Assuming all mast cell tumors behave the same-grade and c-kit status matter.
- Overlooking that hypercalcemia may be paraneoplastic (lymphoma, anal sac adenocarcinoma) rather than primary hyperparathyroidism.
Worked rule of thumb
A dog with a splenic mass and hemoabdomen: stabilize, then consider that hemangiosarcoma is common but not the only diagnosis-histopathology after splenectomy guides prognosis. A dog with a subcutaneous mass: FNA first; if mast cell tumor, grade and stage before deciding on wide excision vs. systemic therapy.