A Multi-Institutional Retrospective Study of 21 Dogs Having Undergone Hypofractionated Radiotherapy for Adrenal...

Area of Science:

• Veterinary Oncology
• Radiation Oncology
• Canine Medicine

Background:

• Adrenal tumors are a significant concern in canine oncology.
• Radiation therapy (RT) is an emerging non-surgical treatment option.
• Hypofractionated image-guided intensity-modulated RT (IMRT) is being explored for efficacy.

Purpose of the Study:

• To evaluate the clinical outcomes of canine adrenal tumors treated with hypofractionated IMRT.
• To assess treatment response, survival rates, and adverse events.
• To determine the potential survival benefit of RT in dogs with adrenal masses.

Main Methods:

• Retrospective, multi-institutional study of 21 dogs with adrenal tumors.
• Treatment involved hypofractionated IMRT (25-35 Gy in 5 fractions over 5-15 days).
• Diagnoses confirmed by imaging and biochemical testing; outcomes assessed via follow-up imaging and survival data.

Main Results:

• Partial response (37.5%) and stable disease (62.5%) observed in dogs with follow-up imaging.
• Mild gastrointestinal side effects in 19% of dogs.
• Median overall survival time of 377 days; 1- and 2-year survival rates of 59.4% and 34.7%.

Conclusions:

• Hypofractionated IMRT is a viable treatment for canine adrenal tumors, potentially prolonging survival.
• RT may offer benefits even in cases with vessel invasion or comorbidities.
• Further research is needed to identify risk factors for early death and optimal patient selection for RT.