Radiation therapy
for pituitary tumors
in pets — Florida.

One tumor, two problems —
radiation targets the tumor.

The pituitary gland sits at the base of the brain. Tumors here — whether microadenomas or macroadenomas — affect two systems simultaneously: they compress brain structures as they grow, and they produce excess hormones that disrupt the body's regulation. Radiation targets the tumor to control its growth and the neurological signs it causes.

In dogs, pituitary tumors are the most common cause of Cushing's disease (hyperadrenocorticism) — a hormonal disorder characterized by increased thirst, urination, pot-belly appearance, hair loss, and skin changes. When the tumor grows large enough to become a macroadenoma, neurological signs emerge: seizures, behavioral changes, circling, visual deficits, and incoordination.

When to consider radiation

Dogs with pituitary-dependent Cushing's disease managed medically but showing neurological signs — or dogs with a confirmed pituitary macroadenoma on MRI — are candidates for radiation therapy. RT is also considered when medical management of Cushing's becomes difficult due to escalating tumor size. Early intervention — before significant neurological damage has occurred — produces better outcomes.

What radiation achieves for pituitary tumors

Radiation controls local tumor growth and relieves intracranial compression. Its effect on hormone levels varies between patients, so medical management of Cushing's disease usually continues and is adjusted over time. Median survival times of 12–20 months have been reported in dogs treated with radiation for pituitary macroadenoma. Many dogs show neurological improvement after treatment.