Raised alkaline phosphatase in a dog with osteosarcoma
8-year-old Rottweiler with lameness and a lytic-proliferative lesion in the distal radius; cytology confirms osteosarcoma and thoracic CT shows no metastases. No corticosteroids have been given.
| Parameter | Result | Reference |
|---|---|---|
| Alkaline phosphatase | 412 U/L | 20–155 |
| Bone ALP isoenzyme | Predominant | — |
| ALT | 38 U/L | 10–100 |
| GGT | 4 U/L | 0–10 |
| Total bilirubin | 0.2 mg/dL | 0.0–0.4 |
Which statement is correct?
chevron_right Show answer and explanation
A. It indicates liver metastases and contraindicates amputation
ALT, GGT and bilirubin are normal and the predominant isoenzyme is bone. Liver metastases are rare at diagnosis of osteosarcoma.
B. It is associated with a shorter disease-free interval and survival
Correct. Raised total or bone alkaline phosphatase before treatment is a recognised negative prognostic factor in canine appendicular osteosarcoma; it reflects greater osteoblastic activity and tumour burden, possibly micrometastatic.
C. It is endogenous stress induction and has no prognostic value
The corticosteroid-induced isoenzyme is different from the bone one. Here the bone fraction predominates, and its rise does carry prognostic value.
D. Suggests osteomyelitis, because osteosarcoma does not raise ALP
Osteosarcoma produces osteoid and can raise bone alkaline phosphatase; moreover, cytology has already confirmed the tumour.
lightbulb Key takeaway
Measure alkaline phosphatase before treating osteosarcoma: if raised (with no hepatic cause or corticosteroids) the prognosis is worse, and failure to normalise after amputation is also unfavourable. It does not contraindicate surgery or adjuvant chemotherapy.
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Updated: November 1, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.