Stereotactic radiation therapy for canine multilobular osteochondrosarcoma: Eight cases

Area of Science:

• Veterinary Oncology
• Radiation Oncology
• Canine Neoplasia

Background:

• Multilobular osteochondrosarcoma (MLO) is a common bone tumor in dogs.
• Radiotherapy is a treatment option for MLO, but data on bulky tumors is limited.

Purpose of the Study:

• To evaluate the clinical outcomes of canine MLO treated with stereotactic radiation therapy (SRT).
• To assess tumor response, survival times, and toxicity associated with SRT for MLO.

Main Methods:

• Retrospective case series of eight dogs with MLO diagnosed via CT scan or pathology.
• Dogs received SRT: 30 Gy in three daily 10 Gy fractions.
• Data collected included demographics, tumor characteristics, dosimetry, toxicity, and outcomes.

Main Results:

• Tumor volume decreased in 4 out of 5 dogs with post-treatment CT scans (26%–87% reduction).
• Median progression-free survival time (MPFST) was 223 days; median overall survival time (MST) was 329 days.
• Late radiation toxicity occurred in 3 dogs (Grade 1 skin/ocular, Grade 3 CNS). Local progression and suspected metastasis were observed.

Conclusions:

• SRT for canine MLO was generally well-tolerated.
• While tumor volume reduction was observed, the duration of response was short-lived.
• Further investigation into optimizing SRT protocols for MLO is warranted.