Pituitary Tumors, from the CureRays guide library.

Pituitary tumors grow in the small hormone-control gland at the base of the brain; most are benign and very treatable, with focused radiation reserved for tumors that persist after surgery or medication.

What it is.

A pituitary tumor is a growth in the pituitary gland, a pea-sized gland that sits at the base of the brain, just behind the eyes, and acts as the body's master hormone controller — directing the thyroid, adrenal glands, growth, reproduction, and more. The great majority of pituitary tumors are benign (non-cancerous) growths called adenomas; true pituitary cancer is extremely rare. Even though they are usually benign, pituitary tumors can cause real problems in two main ways. Some are 'functioning' tumors that make too much of a hormone, leading to conditions such as excess growth hormone (causing acromegaly), excess prolactin (causing changes in menstruation, milk production, or fertility), or excess stress hormone (causing Cushing's disease). Others are 'non-functioning' and cause trouble mainly by their size — pressing on the nearby optic nerves to blur or narrow vision, causing headaches, or crowding the normal gland so it makes too little hormone. Because of the gland's central role and delicate location near the optic nerves, care is provided by a team that typically includes hormone specialists (endocrinologists), neurosurgeons, and radiation oncologists, who tailor treatment to the tumor's type, size, and hormone activity.

How radiation treats it.

Radiation uses focused high-energy beams to damage the DNA inside tumor cells so they gradually stop growing and, for functioning tumors, slowly reduce their hormone overproduction. For pituitary tumors, radiation is usually not the first treatment — surgery and medication come first — but it is a valuable tool when a tumor persists or comes back after surgery, when surgery is not possible, or when hormone levels stay high. Because the pituitary sits just below the optic nerves, the central goal of treatment is to control the tumor while protecting vision and the surrounding brain. Modern techniques make this possible: stereotactic radiosurgery delivers a precise dose in a single session to a well-defined target, while fractionated stereotactic radiotherapy spreads the dose over several gentle sessions when the tumor lies very close to the optic nerves. Radiation works gradually, so tumor control and hormone improvement develop over months to years, and your team monitors hormone levels and vision over the long term. Treatment is painless during delivery. Your radiation oncologist and endocrinologist will explain whether radiation is the right step for your specific tumor.

The ways we can treat it.

Stereotactic radiosurgery. A single, highly focused session (for example with Gamma Knife or similar systems) delivers a precise dose to a well-defined tumor remnant while sharply limiting dose to the optic nerves and normal gland.

Fractionated stereotactic radiotherapy. When a tumor sits very close to the optic nerves, the dose is spread over several gentle sessions to protect vision while still controlling the tumor.

Proton therapy. Proton beams stop precisely at the target and spare surrounding brain tissue, an option for selected tumors where reducing dose to healthy areas is especially important.

Questions we hear often.

Is a pituitary tumor cancer? Almost always, no. The great majority of pituitary tumors are benign growths called adenomas, not cancer. True pituitary cancer is extremely rare. Even though they are benign, these tumors can still need treatment because they may overproduce hormones or press on nearby structures like the optic nerves.

Will I need radiation? Most people do not. Many pituitary tumors are managed with monitoring, medication, or surgery. Radiation is reserved for tumors that persist or regrow after surgery, that cannot be operated on, or that keep overproducing hormones. Your team will tell you whether it applies to your situation.

Will treatment affect my hormones? It can, in either direction. Treating a functioning tumor lowers the excess hormone it was making, which is the goal. Surgery or radiation can also sometimes leave the gland making too little of one or more hormones, in which case safe hormone replacement, guided by an endocrinologist, keeps your body in balance.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.