Musculoskeletal neoplasia

Question 1

In a study by Nakano 2022 in JAVMA, what was the rate of distant metastasis following amputation for appendicular osteosarcoma in cats? What was the MST?

Answer 1

42% rate of distant metastatic disease following amputation (particularly high incidence with osteosarcoma of the humerus).

MST was 527 days.

Question 2

In a study by Crooks 2021 in VRU, what was the detection rate of PET/CT in detecting metastatic or comorbid neoplasia in dogs with primary appendicular osteosarcoma? What agent was used for detection?

Answer 2

24% of dogs had metastatic disease on PET/CT, and 16% had comorbid conditions.

18F-FDG (or Fluorine-18-fluorodeoxyglucose was used as the agent for testing). Increased uptake indicates increased glucose metabolism in the selected tissue, most commonly secondary to neoplasia or inflammation.

Question 3

In a study by Martin 2022 in VRU, what was the MST for dogs with appendicular osteosarcoma undergoing stereotactic radiation therapy with <40% or >40% of the bone affected?

Answer 3

<40%: 256 day survival
>40%: 178 day survival

Increased subchondral bone lysis was associated with an increased risk of pathologic fracture during treatment.