Active Surveillance for Low-Risk Thyroid Cancer: What the Latest JAMA Surgery Study Tells Us

Every week I see patients who have been told they have thyroid cancer and need surgery — immediately. They come in frightened, having already scheduled their operation, sometimes having already told their families.

And sometimes, after reviewing their ultrasound and biopsy results carefully, I have to tell them something that surprises them: you may not need surgery at all.

A new study published in JAMA Surgery in 2025 — Saw et al., volume 160, pages 1117–1124 — adds important evidence to a growing body of research supporting active surveillance as a safe alternative to immediate surgery for carefully selected patients with low-risk papillary thyroid microcarcinoma (PTMC).

Let me explain what this study found, what it means for patients, and how I apply this evidence in my practice.

Citation: Saw ECH, et al. Active Surveillance vs Immediate Surgery for Low-Risk Papillary Thyroid Microcarcinoma. JAMA Surg. 2025;160(10):1117–1124.

The researchers analyzed outcomes in 222 patients with low-risk papillary thyroid microcarcinoma who were managed either with active surveillance (AS) or immediate surgery. Patients in the AS group were monitored with serial ultrasound and clinical evaluation; surgery was performed if the tumor grew by ≥3 mm, developed high-risk features, or the patient requested it.

The key findings:

• No disease-specific deaths in either group
• No distant metastases in the active surveillance group
• Tumor progression requiring surgery occurred in a minority of AS patients — consistent with prior studies showing 3–5% progression rates at 10 years
• Patients who eventually required surgery after a period of AS had outcomes equivalent to those who had immediate surgery — demonstrating that a period of observation does not compromise the cure rate
• Quality of life was comparable between groups, with AS patients reporting high satisfaction with their management

This study confirms what the Japanese experience — now spanning over 30 years and thousands of patients — has already established: for carefully selected patients with low-risk PTMC, active surveillance is safe, and immediate surgery is not required.

Papillary thyroid microcarcinoma is defined as a papillary thyroid cancer measuring 1 cm or less in greatest dimension. It is the most common thyroid cancer and, in its low-risk form, one of the most indolent cancers in all of medicine.

Autopsy studies consistently find occult PTMC in 5–36% of the general population — people who died of completely unrelated causes and never knew they had thyroid cancer. This tells us something important: the vast majority of PTMCs never cause symptoms, never spread, and never kill.

The challenge is that modern ultrasound technology has dramatically increased our ability to detect these tiny tumors. We are now finding cancers that, in a previous era, would never have been discovered. The question is: does finding them mean we must treat them?

For low-risk PTMC, the answer — increasingly supported by evidence — is no.

Active surveillance for low-risk PTMC was pioneered in Japan in the 1990s by Dr. Yasuhiro Ito and colleagues at Kuma Hospital in Kobe. Their landmark study, now with follow-up exceeding 20 years and over 1,800 patients, showed:

• Only 3.8% of patients showed tumor enlargement ≥3 mm at 10 years
• Only 1.7% developed lymph node metastases at 10 years
• Disease-specific survival: 100%
• Among patients who eventually required surgery, outcomes were identical to those who had immediate surgery

These results were initially met with skepticism in the United States, where the default response to any cancer diagnosis has historically been immediate treatment. But the evidence has accumulated, and American guidelines have caught up.

The American Thyroid Association (ATA) 2015 guidelines endorsed AS as an acceptable management option for low-risk PTMC. The 2023 ATA update reaffirmed this position. The Saw et al. 2025 JAMA Surgery study adds further confirmation from a Western patient population.

Not every patient with PTMC is a candidate for AS. The selection criteria are strict, and they exist for good reason — AS is appropriate only when the risk of tumor progression is genuinely low.

Candidates for active surveillance must have ALL of the following:

1. Tumor size ≤1 cm — the microcarcinoma definition
2. No extrathyroidal extension — the tumor is confined within the thyroid capsule
3. No lymph node or distant metastases on ultrasound and clinical examination
4. No high-risk ultrasound features — no irregular margins, no microcalcifications, no taller-than-wide shape, no marked hypoechogenicity
5. Tumor location away from the trachea and recurrent laryngeal nerve — tumors abutting these structures carry higher risk and are better treated surgically
6. No aggressive histologic variants — tall cell, columnar cell, and hobnail variants are more aggressive and require surgery
7. Patient willingness and ability to comply with monitoring — AS requires reliable follow-up; patients who cannot or will not return for regular ultrasounds are not good candidates

Active surveillance is NOT appropriate for:

• Tumors >1 cm
• Any high-risk ultrasound or pathologic features
• Tumors abutting the trachea or recurrent laryngeal nerve
• Lymph node metastases
• Patients with prior neck radiation
• Patients with a strong family history of aggressive thyroid cancer

When I counsel patients about active surveillance, I always discuss what surgery involves — because the risks of thyroid surgery are real, even in expert hands.

Thyroidectomy carries:

• Permanent hypoparathyroidism (low calcium): 1–3% — requires lifelong calcium and vitamin D supplementation; can cause muscle cramps, numbness, and in severe cases, seizures
• Permanent recurrent laryngeal nerve injury (voice change): 1–2% — hoarseness, voice fatigue, or in bilateral cases, breathing difficulty
• Lifelong levothyroxine dependence after total thyroidectomy — requires daily medication and regular monitoring
• General anesthesia risks — small but real, particularly in older patients or those with cardiac or pulmonary disease
• Surgical scar — a permanent neck incision

For a 6mm tumor that has a 95%+ chance of never growing or spreading, these risks deserve serious consideration. Active surveillance eliminates surgical risk entirely for the majority of patients who will never need an operation.

I want to be honest about something: living with a known cancer diagnosis — even a tiny, low-risk one — is psychologically difficult for many patients.

The word "cancer" triggers fear. Patients worry about the tumor growing, spreading, being missed. They want it out. This is a completely understandable response, and I respect it.

Some patients, after thorough counseling about the evidence, still choose immediate surgery. That is a valid choice. My job is not to push AS on anyone — it is to ensure that every eligible patient knows it is an option, understands the evidence, and makes a truly informed decision.

Studies show that with proper counseling, the majority of patients offered AS choose it — and report high satisfaction and quality of life. The key is a physician who takes the time to explain the evidence carefully, answer every question honestly, and provide the reassurance that comes from regular, expert monitoring.

When I identify a patient as a candidate for AS, here is my approach:

Initial evaluation:

• High-resolution thyroid ultrasound with careful measurement and documentation of tumor location, size, and features
• Review of all biopsy material — I want to confirm the diagnosis and verify the histologic subtype
• Assessment of lymph nodes in the central and lateral neck compartments
• Discussion of the evidence, the monitoring protocol, and the criteria for recommending surgery

Monitoring protocol:

• Ultrasound every 6 months for the first 2 years
• If stable at 2 years, annually thereafter
• Clinical examination and thyroid function tests at each visit
• Immediate evaluation if the patient develops new symptoms (neck mass, voice change, difficulty swallowing)

Criteria for recommending surgery:

• Tumor growth ≥3 mm in any dimension
• New high-risk ultrasound features
• New lymph node metastases
• Patient preference for surgery after counseling

I maintain a low threshold for recommending surgery if any concerning change appears. The goal of AS is not to avoid surgery at all costs — it is to avoid unnecessary surgery while remaining vigilant for the minority of tumors that do progress.

Patricia, 58, was referred to me after a neck ultrasound incidentally found a 6mm thyroid nodule. Fine-needle aspiration confirmed papillary thyroid microcarcinoma. Her surgeon recommended immediate thyroidectomy.

Patricia was understandably frightened — but she was also on blood thinners for a heart condition, making surgery risky. I reviewed her ultrasound carefully: the tumor was well away from the trachea and recurrent laryngeal nerve, with no lymph node involvement and no high-risk features.

I offered active surveillance. We discussed the Kuma Hospital data, the ATA guidelines, and what monitoring would involve. Patricia chose AS.

Over four years of twice-yearly ultrasounds, her tumor has not grown by a single millimeter. She has avoided surgery entirely — and all the risks that would have come with it given her cardiac status.

"I was terrified when I heard the word cancer," she told me. "Now I understand that watching carefully is the right treatment for my situation."

That understanding — that not every cancer requires immediate aggressive treatment — is one of the most important things I can offer a patient.

I have been practicing thyroid medicine for over 50 years. I have watched the pendulum swing from under-treatment to over-treatment and back again.

The thyroid cancer epidemic of the past two decades is, in large part, an epidemic of detection — not an epidemic of disease. We are finding tiny tumors that would never have caused symptoms or shortened lives. And we have been operating on them at enormous scale, exposing patients to surgical risks for cancers that would never have harmed them.

Active surveillance is the correction. It is not reckless — it is evidence-based, guideline-endorsed, and backed by 30 years of Japanese data and now a growing body of Western evidence including the 2025 JAMA Surgery study.

For the right patient, AS is not the easy way out. It is the right way in.

Reference: Saw ECH, et al. Active Surveillance vs Immediate Surgery for Low-Risk Papillary Thyroid Microcarcinoma. JAMA Surg. 2025;160(10):1117–1124.

Dr. Guttler has practiced thyroid medicine for over 50 years and has offered active surveillance to appropriate patients long before it became mainstream in American guidelines. He offers consultations for patients with low-risk thyroid cancer who want to understand all their options.