Thyroid Cancer: Understanding Types, Radioactive Iodine Therapy, and Thyroidectomy

Thyroid cancer is one of the fastest-growing cancer diagnoses in the U.S., with nearly 44,000 new cases each year. But here’s the surprising part: most people diagnosed with it live long, healthy lives. The key? Knowing the type, understanding the treatment options, and avoiding unnecessary interventions. This isn’t just about surgery or radiation-it’s about making smart, personalized choices based on real data, not fear.

What Are the Main Types of Thyroid Cancer?

Not all thyroid cancers are the same. They’re named after the cells they come from, and that determines how they behave and how they’re treated.

Papillary thyroid carcinoma (PTC) makes up 70 to 80% of cases. It grows slowly, often stays inside the thyroid, and responds extremely well to treatment. Even when it spreads to nearby lymph nodes, the 10-year survival rate for people under 45 is over 98%. It’s the most common type-and often the least dangerous.

Follicular thyroid carcinoma (FTC) accounts for 10 to 15% of cases. It’s similar to PTC but more likely to spread through the bloodstream to the lungs or bones. Still, if caught early, it’s highly treatable.

Medullary thyroid carcinoma (MTC) is rarer, at 3 to 5%. It starts in the C-cells, which make calcitonin, not thyroid hormone. Some cases are inherited, linked to genetic mutations like RET. This type doesn’t absorb iodine, so radioactive iodine therapy won’t work. Surgery is the main treatment.

Anaplastic thyroid carcinoma (ATC) is the rarest-less than 2%-but also the most aggressive. It grows fast, spreads quickly, and is often diagnosed at stage IV. Survival rates drop sharply if treatment is delayed. The good news? New targeted drugs like dabrafenib and trametinib have doubled median survival for patients with BRAF mutations.

Why Radioactive Iodine Therapy Is Used (and When It’s Not)

Radioactive iodine therapy (RAI), or I-131, has been used since the 1940s. It works because thyroid cells-both healthy and cancerous-absorb iodine. When you swallow a capsule or liquid containing I-131, the radiation destroys any remaining thyroid tissue after surgery.

But RAI isn’t for everyone. It only works on cancers that still act like normal thyroid cells-so it’s effective for papillary and follicular cancers, but useless for medullary and anaplastic types.

For low-risk patients-those with tumors under 1 cm and no spread-studies show no benefit from RAI. The HiLo trial found that 30 mCi doses work just as well as 100 mCi for ablation, cutting radiation exposure by 70%. Many doctors now skip RAI entirely for small, low-risk tumors.

Preparing for RAI used to mean going weeks without thyroid hormone, causing fatigue, brain fog, and weight gain. Now, most patients get injections of recombinant human TSH (Thyrogen®), which stimulates thyroid cells without making you hypothyroid. It’s easier, safer, and more comfortable.

Still, RAI has downsides. Some patients report dry mouth, taste changes, or even secondary cancers years later. A 2019 study found 58% of patients had dry mouth six months after treatment. For those with advanced disease, it’s life-saving. For others, it’s an over-treatment.

Thyroidectomy: What Surgery Really Involves

Surgery is the foundation of thyroid cancer treatment. The type of surgery depends on the cancer’s size, type, and spread.

Lobectomy removes one lobe of the thyroid. It’s often enough for small, low-risk papillary cancers. Recovery is quick-most people go home the same day. The incision is 4 to 6 cm, and complications like nerve damage are rare.

Total thyroidectomy removes the entire gland. This is standard for larger tumors, cancers that have spread, or when RAI is planned. The incision is 6 to 8 cm. Surgeons now use nerve monitors to protect the vocal cords, cutting injury rates from 12% down to under 5%.

Completion thyroidectomy is done if a patient had a lobectomy first, and later tests show cancer was more extensive than thought. It’s a second surgery, but less complex than the first.

Some patients ask about scarless options like transoral or robotic surgery. These are possible, but not better. A 2020 meta-analysis found robotic approaches had higher complication rates (12.4% vs. 8.9%) and no proven survival benefit. Open surgery still gives surgeons the clearest view and best control.

After surgery, you’ll need lifelong thyroid hormone replacement (levothyroxine). The dose isn’t just to replace function-it’s often raised to suppress TSH and lower cancer recurrence risk. For intermediate-risk patients, doctors aim for a TSH level between 0.5 and 2.0 mIU/L.

What Happens After Treatment?

Recovery isn’t just about healing the neck. Many patients struggle with ongoing symptoms-even after their cancer is gone.

A 2023 survey of over 1,200 thyroid cancer survivors found 68% still felt fatigued or mentally foggy despite taking their hormone pills. That’s not normal hypothyroidism. It’s something deeper, possibly tied to how the body adjusts to synthetic hormone.

Another common issue: calcium levels. The parathyroid glands sit right behind the thyroid. During surgery, they can get damaged or temporarily shut down. About 22% of total thyroidectomy patients need long-term calcium and vitamin D supplements. Checking calcium levels weekly after surgery isn’t optional-it’s essential.

Voice changes are also common. Hoarseness usually clears up in weeks, but 31% of patients report lasting changes. That’s why nerve monitoring during surgery matters so much.

Follow-up care includes regular blood tests (TSH, thyroglobulin), neck ultrasounds, and sometimes whole-body scans. For most, these visits become less frequent over time. But staying on schedule is critical-recurrence can happen years later.

When Less Is More: The Shift Away from Overtreatment

For years, the default was aggressive: remove everything, give radiation, push hormone suppression. But new data is changing that.

Dr. Leonard Wartofsky and others have shown that tiny papillary cancers under 1 cm-called microcarcinomas-often never grow. In Japan, where active surveillance is common, only 3.8% of these tumors progressed over 10 years. That’s why the 2015 American Thyroid Association guidelines now recommend observation for low-risk cases, not surgery.

Dr. David Ain says up to 30% of thyroid cancer patients get overtreated. That means unnecessary surgery, radiation, and lifelong hormone therapy for cancers that would never harm them.

But here’s the balance: if you have a tumor over 1 cm, lymph node spread, or a family history of thyroid cancer, you need treatment. The goal isn’t to avoid all treatment-it’s to avoid the wrong treatment.

What’s New in Thyroid Cancer Treatment?

The field is moving fast. In 2021, the FDA approved selpercatinib for RET-mutant medullary thyroid cancer. It’s a targeted pill that blocks the specific mutation driving the cancer. For some, it shrinks tumors without surgery.

For anaplastic cancer, the combination of dabrafenib and trametinib (used for melanoma) has pushed median survival from 5.3 months to over 10 months. That’s huge for a disease that used to be a death sentence.

Researchers are now testing drugs that can “redifferentiate” cancer cells-making them absorb iodine again. Selumetinib showed promise in trials, with 54% of RAI-resistant patients regaining iodine uptake.

Future tools include liquid biopsies-blood tests that detect cancer DNA. They could replace painful scans and catch recurrence earlier.

What You Need to Know Before Making a Decision

If you’re facing a thyroid cancer diagnosis, here’s what to ask:

• What type of cancer do I have? (Papillary? Follicular? Medullary?)
• What’s the size? Has it spread beyond the thyroid?
• Do I need a lobectomy or a total thyroidectomy?
• Will I need radioactive iodine? Is my cancer likely to absorb it?
• Can I try active surveillance instead of surgery?
• What are the risks of nerve damage or low calcium?
• Who will manage my thyroid hormone levels after surgery?

Don’t rush. Get a second opinion. Ask for a copy of your pathology report. And remember: thyroid cancer is not one disease. Your treatment should be as unique as your diagnosis.