When is Traditional Radiation Therapy Used for Thyroid Cancer?

“Thyroid cancer is an umbrella term for many different types of thyroid cancer based on what it looks like under the microscope,” Dr. Jessica Geiger, a medical oncologist at  Cleveland Clinic, tells SurvivorNet.

“This could be papillary thyroid cancer, follicular thyroid cancer or Hurthle cell. There’s another entity poorly differentiated thyroid cancer, medullary thyroid cancer, which is completely separate and a lot of times related to genetic or familial collection of other endocrinopathy and other diseases.”

Thyroid Cancer Types

The term “thyroid cancer” covers several types of cancer with varying levels of aggressiveness, including:

• Papillary and Follicular Thyroid Cancers: These often respond well to surgery and radioactive iodine (RAI). In most cases, they’re highly curable.
• Medullary Thyroid Cancer: These originate in the thyroid’s C cells. They sometimes require genetic testing, special medications, and, in certain situations, radiation therapy.
• Anaplastic Thyroid Cancer: This is a rare but extremely aggressive form that frequently requires a combination of treatments, often including radiation, to control the disease quickly.

Challenges in Advanced Disease

Even the “easier” versions of thyroid cancer can sometimes become advanced if they spread (metastasize) to parts of the body beyond the neck, such as the lungs, bones, or liver. In such scenarios, your care team may have tried (or considered) surgery or radioactive iodine therapy. However, if the cancer grows back, or if you have a thyroid cancer type that doesn’t respond well to these approaches (like anaplastic thyroid cancer), additional tools are needed.

One key therapy at this stage is external beam radiation — also called conventional or traditional radiation therapy.

Radiation’s Role in Thyroid Cancer Treatment

“In advanced thyroid cancer, we’re often leaning on other medical specialists to help us treat our patients to the best that we can. One of my specialty colleagues is in radiation oncology. This is standard external beam radiation that you think of when you think of radiation for cancer. This is not radioactive iodine; this is using beams of radiation to kill cancer,” Dr. Geiger explains.

When many people hear “radiation” in the context of thyroid cancer, they may automatically think of radioactive iodine (RAI) — which is highly effective for certain thyroid cancer subtypes that still behave like normal thyroid cells. Yet RAI isn’t the same as external beam radiation:

• With Radioactive Iodine, a swallowable capsule or liquid travels throughout your body, zeroing in on any remaining thyroid tissue.
• With External Beam Radiation, high-energy beams from a machine outside your body are aimed precisely at tumors.

For advanced or aggressive thyroid cancer, external beam radiation can be used in specific ways to help relieve symptoms, control tumor growth, or even prolong survival. It often works best when combined with other treatments or used in very targeted situations.

“We often use these for what I term … spot welding,” Dr. Geiger explains. “… If a patient is on systemic therapy or even under active surveillance, but there’s one pesky tumor that’s in the hip bone, for example, it’s very painful. It’s a weight-bearing bone causing a lot of problems. We can spot weld and use some radiation with our radiation oncology colleagues to sort of just zap that area and everything else we can keep under active surveillance.”

In advanced thyroid cancer, you might have a tumor or “spot” that is growing quickly or pressing on a crucial area — such as the airway, spine, or bones — but the rest of the cancer is either stable or slow-growing. In these situations, your medical team might recommend “spot-welding” with radiation.

Also, anaplastic thyroid cancer typically demands immediate, aggressive treatment. Doctors often coordinate quickly to confirm the diagnosis and start therapy without delay. Radiation is frequently a core part of this plan — especially if surgery can’t remove every trace of cancer in the neck, or if there’s a high likelihood of local spread.

How Radiation Therapy Works

The Basics

External beam radiation uses high-energy X-rays (or sometimes protons or other forms of radiation) directed at the affected area. The goal: damage the DNA of thyroid cancer cells so they stop growing and eventually die off, while limiting harm to surrounding healthy tissues as much as possible.

The Multi-Disciplinary Team

Many specialists collaborate on advanced thyroid cancer management, including:

• Endocrinologists: Monitor hormones and thyroid function, especially if you’ve had surgery or part of your thyroid removed
• Head and Neck Surgeons: Operate if removal of a tumor is feasible
• Radiation Oncologists: Design and deliver the radiation therapy plan
• Medical Oncologists: Oversee chemotherapy, targeted therapies, or other systemic treatments (especially for anaplastic or widely spread disease)

Preparing for Treatment

Simulation and Mapping

Steps before your first radiation session might include:

• Imaging: You’ll typically undergo a CT scan or sometimes an MRI. These help your radiation oncologist see the precise tumor location and nearby structures.
• Positioning: The team may create a special immobilization mask or use pillows and cushions to make sure you stay in exactly the same position every time. This ensures that the radiation hits only the intended area.
• Marking and Planning: Using sophisticated software, the radiation oncologist maps out the tumor and calculates how best to deliver rays from different angles to spare healthy tissue.

What If You’ve Had Surgery?

If you’ve recently had a thyroidectomy (removal of the thyroid) or neck dissection (removal of lymph nodes), your medical team waits until your incisions heal. Once you’re ready, they can plan the radiation fields accordingly — sometimes focusing on the “bed” where the thyroid used to be, or specific high-risk zones.

What Happens During Radiation Sessions

The Treatment Routine

• Daily Visits: Most external beam radiation treatments happen Monday through Friday for several weeks, depending on your plan. Each session usually lasts 15 to 30 minutes, although the actual beam time is much shorter.
• No Hospital Stay: You go home the same day.
• Painless Delivery: You don’t feel pain during the beam, though you might hear the machine buzzing or whirring as it moves around you.

Staying Still

Your job is mostly to hold still while the machine (called a linear accelerator) moves around you to aim the radiation beams. The therapists may ask you to breathe normally or hold your breath briefly, depending on the tumor’s location.

Possible Benefits and Goals of Radiation

If a tumor is pressing on nerves or bones, causing pain, or obstructing your airway, radiation can shrink it and offer relief. Patients often feel improvement in swallowing or reduced pain a few weeks into therapy.

Even if your thyroid cancer has traveled beyond the neck, you might have a specific area that’s growing too quickly or risking complications. “Spot welding” can help maintain control in that region so you can continue everyday activities.

For patients with very aggressive thyroid tumors — like some anaplastic, poorly differentiated, or advanced medullary subtypes — radiation after surgery can “sterilize” leftover microscopic disease. This lowers the risk of rapid local recurrence.

Some advanced thyroid cancers threaten essential functions, such as breathing or speech. Radiation can also reduce the tumor burden enough to protect the airway, vocal cords, or swallowing mechanism.

Risks and Side Effects

Short-term side effects associated with radiation include:

• Skin Reactions: The radiation beam can cause skin redness, dryness, or a sunburn-like effect on your neck. Gentle skincare products and instructions from your care team help minimize discomfort.
• Mouth and Throat Irritation: If radiation hits areas inside your mouth or throat, swallowing might become painful or challenging. This can also reduce taste or cause dryness from affected salivary glands.
• Fatigue: Feeling unusually tired is common during and after radiation. Extra rest and mild exercise can help you cope.

Long-term side effects from radiation treatment might include:

• Scarring and Lymphedema: Tissues in the neck may become tight or swollen. A specialized therapist can teach exercises or massages to manage lymphedema.
• Permanent Dry Mouth: If the salivary glands are significantly affected, you might have chronic dryness, which can change how food tastes or affect oral health.
• Voice Changes: If radiation involves the voice box area (larynx), some patients develop hoarseness or voice fatigue.
• Rare But Serious Complications: In the advanced stage, doctors aim to protect nerves, swallowing muscles, and spinal structures. Even so, there’s always a risk of damage over time.

Your radiation oncologist and medical oncologist will carefully weigh the potential rewards — stopping tumor growth, safeguarding critical functions, etc. — against these side effects. They often adjust your treatment fields or total dose to reduce damage to healthy tissues.

Living Well During and After Radiation

Patients can follow some simple tips to help them tolerate radiation treatment better.

Consider the following:

• Stay Hydrated: If your throat is sore, cold or lukewarm fluids can be soothing.
• Use Gentle Skin Care: Ask your radiation team which lotions or creams are safe.
• Try Soft Foods: Pureed or soft meals might be easier to swallow if your mouth or throat is irritated.
• Speak Up About Pain: Don’t suffer in silence — medications or mouth rinses can make eating and drinking more comfortable.
• Conserve Energy: Simplify daily tasks, and let friends or family help with errands if fatigue sets in.

You’ll also likely see your doctors periodically during the course of radiation to address any immediate side effects. After treatment ends, you’ll have scheduled follow-ups to gauge how well the cancer responded and to manage any ongoing issues.

Questions to Ask Your Doctor

• Do you recommend radiation therapy for my cancer?
• What should I do to prepare before treatment?
• What sort of radiation schedule will I be on?
• What sort of side effects can I expect after treatment ends?

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