Author: Rodrigo Arrangoiz MS, MD, FACS, FSSO

Hürthle cell carcinoma (HCC) is a distinct subtype of differentiated thyroid cancer, accounting for ~3–5% of cases. Although related to follicular tumors, it behaves differently and requires specific management considerations.

🧠 Key characteristics of Hürthle cell carcinoma

Composed of oncocytic (Hürthle) cells rich in mitochondria More common in older patients Less likely to spread to lymph nodes More likely to spread hematogenously (lungs, bone) in higher-risk disease Often less iodine-avid than papillary or follicular thyroid cancer

🔍 How is it diagnosed?

Ultrasound and FNA may suggest a Hürthle cell neoplasm Definitive diagnosis requires surgery, based on: Capsular invasion Vascular invasion

➡️ Cytology alone cannot reliably distinguish benign from malignant Hürthle cell tumors.

⚖️ How is Hürthle cell carcinoma treated?

Management is risk-adapted and may include:

Thyroid lobectomy for small, minimally invasive tumors Total thyroidectomy for larger or invasive disease Radioactive iodine selectively (often less effective than in other subtypes) Close long-term surveillance

📈 Prognosis

Excellent outcomes for minimally invasive disease Prognosis worsens with: Extensive vascular invasion Large tumor size Distant metastases

🦋 Careful pathology review and individualized treatment are essential.

👨‍⚕️ Dr. Rodrigo Arrangoiz, MD

Surgical Oncologist – Thyroid, Head & Neck, Breast

Mount Sinai Medical Center

📌 Take-home message:

Hürthle cell carcinoma is uncommon but highly treatable when managed by an experienced thyroid team.

📚 References

Haugen BR et al. ATA Guidelines for Differentiated Thyroid Cancer. Thyroid Lloyd RV et al. WHO Classification of Tumours of Endocrine Organs Ganly I et al. Hürthle cell carcinoma outcomes. J Clin Endocrinol Metab

Follicular thyroid cancer (FTC) accounts for ~10–15% of thyroid cancers. While less common than papillary thyroid cancer, it is still highly treatable, especially when diagnosed early.

🧠 Key characteristics of FTC

Tends to spread through the bloodstream rather than lymph nodes Can metastasize to lungs or bones (uncommon, usually in higher-risk disease) Often appears similar to benign nodules on ultrasound Diagnosis depends on capsular and/or vascular invasion, which cannot be confirmed by FNA alone

🔍 How is FTC diagnosed?

Ultrasound and FNA may suggest a follicular neoplasm Definitive diagnosis requires surgery and full histologic evaluation Pathology distinguishes: Minimally invasive FTC Widely invasive FTC

⚖️ How is follicular thyroid cancer treated?

Management is risk-adapted and may include:

Thyroid lobectomy for minimally invasive, low-risk tumors Total thyroidectomy for higher-risk disease Radioactive iodine selectively for tumors with vascular invasion or metastases Long-term surveillance with thyroglobulin and imaging

📈 Prognosis

Excellent outcomes for minimally invasive FTC Prognosis depends on: Degree of vascular invasion Tumor size Patient age

🦋 Early, appropriate management leads to very high cure rates.

👨‍⚕️ Dr. Rodrigo Arrangoiz, MD

Surgical Oncologist – Thyroid, Head & Neck, Breast

Mount Sinai Medical Center

📌 Take-home message:

Follicular thyroid cancer often requires surgery for diagnosis, but when managed correctly, outcomes are excellent.

📚 References

Haugen BR et al. ATA Guidelines for Differentiated Thyroid Cancer. Thyroid Lloyd RV et al. WHO Classification of Tumours of Endocrine Organs. Tuttle RM et al. Risk-adapted management of differentiated thyroid cancer. Lancet Diabetes Endocrinol

Papillary thyroid cancer (PTC) accounts for ~80–85% of all thyroid cancers. It is also the subtype with the best overall prognosis.

🧠 Key characteristics of PTC

Typically slow-growing Often diagnosed at an early stage May spread to neck lymph nodes, especially in younger patients Even with lymph node involvement, long-term survival remains excellent

🔍 How is PTC usually detected?

Incidentally on high-resolution ultrasound Confirmed with ultrasound-guided FNA biopsy Often small tumors (≤2 cm) at diagnosis

⚖️ How is papillary thyroid cancer treated?

Treatment is risk-adapted and may include:

Active surveillance for selected very low-risk tumors Thyroid lobectomy for low-risk disease Total thyroidectomy for higher-risk cases Selective lymph node surgery when indicated Radioactive iodine only for patients who truly benefit

➡️ Not all patients need the same treatment.

📈 Prognosis

10-year survival >95% Many patients live normal lifespans Focus is increasingly on quality of life, not just cure

👨‍⚕️ Dr. Rodrigo Arrangoiz, MD

Surgical Oncologist – Thyroid, Head & Neck, Breast

Mount Sinai Medical Center

📌 Take-home message:

Papillary thyroid cancer is common, highly treatable, and often requires less aggressive treatment than patients expect.

📚 References

Haugen BR et al. ATA Guidelines for Differentiated Thyroid Cancer. Thyroid Tuttle RM et al. Risk-adapted management of papillary thyroid cancer. Lancet Diabetes Endocrinol SEER Cancer Statistics Review

Radioactive Iodine (RAI) for Thyroid Cancer – Who Really Needs It in 2026?

Radioactive iodine (RAI, I-131) is used after thyroid surgery in selected cases of differentiated thyroid cancer (papillary and follicular). Its goals are:

to destroy tiny remnants of thyroid tissue (“remnant ablation”), to reduce the risk of recurrence (“adjuvant therapy”), or to treat known persistent or metastatic disease. 

Over the last decade, we’ve learned that many low-risk patients do just as well without RAI, so we now use it much more selectively.

1. When is RAI usually recommended?

Most societies (ATA, ETA, NCCN, SNMMI/EANM) and recent data support using RAI mainly for intermediate- and high-risk disease. 

RAI is typically recommended when:

High-risk disease (ATA high risk) Gross extrathyroidal extension Large primary tumors Extensive nodal disease (multiple or large metastatic nodes) Distant metastases (lung, bone, etc.)  Selected intermediate-risk disease Microscopic extrathyroidal extension Multiple involved lymph nodes Aggressive histologic variants Here, RAI is considered and individualized based on age, tumor biology, thyroglobulin, and patient preferences.  Persistent or recurrent disease Elevated or rising thyroglobulin after surgery Iodine-avid metastatic disease on imaging 

2. When is RAI often not needed?

For many patients with true low-risk differentiated thyroid cancer, excellent outcomes can be achieved with surgery and careful follow-up without RAI.

The ESTIMABL2 randomized trial showed that in low-risk patients (small, node-negative tumors), follow-up without RAI was non-inferior to routine RAI at 5 years, with no loss of oncologic opportunity.  The 2015 ATA guidelines and subsequent analyses recommend that RAI is not routinely used in ATA low-risk patients, particularly for tumors ≤4 cm without worrisome features. 

For many patients, this means less treatment, fewer side effects, and the same excellent prognosis.

3. Common short-term side effects

Most side effects are mild and temporary:

Neck discomfort or swelling Nausea, metallic taste, or loss of taste Dry mouth or thick saliva Swollen, tender salivary glands (parotid/submandibular sialadenitis) Fatigue for days to weeks Temporary changes in blood counts (mild bone-marrow suppression) 

Some patients also report:

Dry eyes, tearing problems, or a “gritty” sensation Nasal dryness and crusting 

4. Less common or long-term risks

These are less frequent but important to discuss before treatment:

Chronic salivary gland dysfunction Persistent dry mouth (xerostomia) Difficulty with chewing/swallowing dry foods Increased dental caries and oral infections  Lacrimal (tear duct) problems Nasolacrimal duct obstruction → watery or irritated eyes Sometimes requires ophthalmology intervention  Fertility and pregnancy Transient effects on sperm parameters and ovarian reserve have been described at higher cumulative doses, so we usually recommend avoiding pregnancy for 6–12 months after RAI and consider sperm banking in selected young men likely to need repeated high-dose treatments.  Second primary malignancies (very rare) Large observational studies suggest a small increase in risk of secondary malignancies (e.g., leukemia, salivary gland tumors) at higher cumulative doses, which reinforces the move toward lower doses and more selective use. 

5. How we minimize and manage side effects

a) Use the lowest effective dose

Trials such as HiLo and related studies have shown that low-dose (≈30 mCi) RAI with recombinant TSH is as effective as higher doses for remnant ablation in low-risk patients, with fewer side effects. 

b) Protect salivary glands

Aggressive hydration for several days after therapy Frequent chewing (sugar-free gum) and sour candies starting after the first 24 hours, as guided by the treating team, to stimulate saliva flow Good oral and dental hygiene, with dental follow-up for patients receiving higher doses In selected patients with significant chronic symptoms, sialogogues (pilocarpine, cevimeline) and targeted ENT/salivary management may help 

c) Protect eyes and tear ducts

Artificial tears and ocular lubricants from the early post-treatment period Early evaluation by ophthalmology if tearing, pain, or recurrent eye infections develop In selected complex cases, interventional approaches to the nasolacrimal duct can be considered. 

d) Monitor blood counts and overall health

Baseline and follow-up blood counts in patients receiving moderate/high doses Correct nutritional deficiencies and manage anemia or other cytopenias if they occur 

e) Clear radiation-safety instructions

Temporary restrictions on close contact with children and pregnant women, sleeping in the same bed, and travel, adapted to the administered dose and national regulations. 

6. Take-home messages for patients

Not everyone with thyroid cancer needs RAI. Many low-risk patients do very well with surgery and surveillance alone. When indicated, RAI can reduce recurrence and treat iodine-avid metastatic disease, particularly in higher-risk patients.  Most side effects are short-term and manageable; long-term complications are less common and are more likely with higher cumulative doses. Careful risk stratification, dose selection, and prevention strategies (hydration, salivary and ocular care, blood count monitoring) are key to minimizing toxicity. Decisions about RAI should be personalized, ideally made in a multidisciplinary team with a thyroid surgeon, endocrinologist, and nuclear medicine specialist.

Suggested references (for the post footer)

Haugen BR, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2016.  Pacini F, et al. What are the indications for post-surgical radioiodine therapy in differentiated thyroid cancer? Eur Thyroid J. 2022.  Leboulleux S, et al. Thyroidectomy without radioiodine in patients with low-risk thyroid cancer (ESTIMABL2, 5-year follow-up). Lancet Diabetes Endocrinol. 2025.  Mallick U, et al. Ablation with low-dose radioiodine and thyrotropin alfa. N Engl J Med. 2012. (HiLo trial)  Nguyen NC, et al. Radioactive Iodine Therapy in Differentiated Thyroid Cancer: An Update on Dose Recommendations and Risk of Secondary Primary Malignancies. Semin Nucl Med. 2024.  Orosco RK, et al. Radioactive iodine in differentiated thyroid cancer. Head Neck. 2019.  Jeong SY, et al. Salivary gland function 5 years after radioactive iodine ablation. J Nucl Med. 2013.  Solans R, et al. Salivary and lacrimal gland dysfunction after radioiodine therapy. J Nucl Med. 2001.  Baudin C, et al. Dysfunction of the salivary and lacrimal glands after radioiodine therapy: START study. Thyroid. 2023.  Rahmanipour E, et al. Eye-related adverse events after I-131 radioiodine therapy: systematic review. Endocr Pract. 2024.  Berta DM, et al. Effect of radioactive iodine therapy on hematological parameters: systematic review and meta-analysis. Front Endocrinol. 2025. 

Author:

Rodrigo Arrangoiz, MD

Surgical Oncologist & Thyroid Surgeon

Mount Sinai Medical Center – Miami, FL

Why Not All Thyroid Cancers Need Aggressive Treatment

Not all thyroid cancers behave the same. Modern care is personalized—the goal is to treat what matters while avoiding unnecessary treatment.

🧠 The key concept: Risk-adapted management

Many thyroid cancers—especially low-risk papillary thyroid cancers—are:

Slow-growing Unlikely to spread Associated with excellent long-term survival

Because of this, more treatment is not always better.

⚖️ Treatment options today

Depending on risk, options may include:

Active surveillance (careful ultrasound follow-up, no immediate surgery) Thyroid lobectomy instead of total thyroidectomy Selective use of radioactive iodine (not routine for everyone)

➡️ These approaches are evidence-based and safe for appropriately selected patients.

📉 Why avoid overtreatment?

Unnecessary aggressive treatment can:

Increase risk of hypocalcemia and voice changes Require lifelong thyroid hormone replacement Affect quality of life without improving outcomes

🦋 What matters most

Treatment decisions should be guided by:

✔️ Tumor size and ultrasound features

✔️ Pathology and risk of recurrence

✔️ Patient age, preferences, and values

✔️ Expertise of a multidisciplinary thyroid team

👨‍⚕️ Dr. Rodrigo Arrangoiz, MD

Surgical Oncologist – Thyroid, Head & Neck, Breast

Mount Sinai Medical Center

📌 Take-home message:

The best thyroid cancer treatment is the right treatment for the right patient—not the most aggressive one.

📚 References

Haugen BR et al. ATA Guidelines for Differentiated Thyroid Cancer. Thyroid Tuttle RM et al. Active surveillance for low-risk papillary thyroid cancer. JAMA Brito JP et al. Overdiagnosis and overtreatment of thyroid cancer. BMJ

• Mucinous breast cancer is a slow-growing neoplasm:

• • With an estimated growth rate of one third of invasive breast cancer no special type

• • This malignancy also shows:

    • Fewer axillary lymph node metastases

• Conventional, pure mucinous carcinomas:

  • Exhibit a rate of metastasis of less than 15%

• Current studies have shown that a subset of patients diagnosed with mucinous carcinoma:

  • Do not manifest such favorable outcomes:

• • • Some authors suggested that specific subtypes of pure mucinous carcinoma:

  • • • Those with a micropapillary pattern demonstrate significantly worse prognosis:

    • • • In one  study more than half of the patients with this particular type of pattern were found to have vascular invasion and synchronous axillary lymph nodes

Age plays an important role in how thyroid cancer behaves, how it is staged, and how it is treated.

👶 Thyroid cancer in younger patients

More common in women Often presents with lymph node involvement Tumors may look aggressive on imaging 👉 Despite this, prognosis is excellent

✔️ Patients under 55 years are staged differently

✔️ Even with lymph nodes, survival rates exceed 98–99%

✔️ Treatment focuses on curing disease while preserving quality of life

👴 Thyroid cancer in older patients

Less common, but tumors may be biologically more aggressive Higher likelihood of: Extrathyroidal extension Distant metastases Higher-stage disease Outcomes are still often very good, but treatment may need to be more comprehensive

⚖️ Why age matters

Age helps determine:

AJCC stage Expected prognosis Intensity of treatment and follow-up

🧠 Important clarification:

Age alone does not determine outcome.

➡️ Tumor biology, pathology, and response to treatment matter most.

🦋 What this means for patients

Thyroid cancer is not the same disease in every patient.

The goal is personalized, risk-adapted care—not one-size-fits-all treatment.

👨‍⚕️ Dr. Rodrigo Arrangoiz, MD

Surgical Oncologist – Thyroid, Head & Neck, Breast

Mount Sinai Medical Center

📌 Take-home message:

Young patients do extremely well.

Older patients still have excellent outcomes with expert, individualized care.

📚 References

AJCC Cancer Staging Manual, 8th Edition Haugen BR et al. ATA Guidelines for Differentiated Thyroid Cancer. Thyroid Tuttle RM et al. Risk-adapted management of thyroid cancer. Lancet Diabetes Endocrinol

• Updated 2018 American Society for Radiation Oncology (ASTRO) guidelines:
  • State that patients 50 and younger, and 51 to 70 years of age with high-grade tumors or positive margins:
    • Should receive a tumor bed boost
  • A boost may be omitted for women:
    • Older than 70 with hormone receptor positive and low- or intermediate-grade disease with widely negative margins (> 2 mm)
  • If the patient does not meet either of those criteria, individualized decision making is recommended
  • For ductal carcinoma in situ (DCIS):
    • Tumor bed boost may be used for women:
      • 50 years of age and younger
      • Close (less than 2 mm) or positive margins
      • High-grade disease
    • It may be omitted for patients:
      • Older than 50 with screening detected
      • Total size less than 2.5 cm
      • Low to intermediate nuclear grade
      • Widely negative margins:
        • Greater than 3 mm
    • Long-term 20-year follow-up of a phase 3 trial of boost vs. no boost:
      • Reported a benefit in all groups with the largest absolute risk reduction in younger patients
• References
  • Smith BD, Bellon JR, Blitzblau R, et al. Radiation therapy for the whole breast: executive summary of an American Society for Radiation Oncology (ASTRO) evidence-based guideline. Pract Radiat Oncol. 2018;8(3):145-152.
  • Bartelink H, Maingon P, Poortmans P, et al. Whole-breast irradiation with or without a boost for patients treated with breast-conserving surgery for early breast cancer: 20-year follow-up of a randomised phase 3 trial. Lanc Oncol. 2015;16(1):47-56.

• The regional state of lymph nodes:
  • Is one of the most important parameters determining prognosis in patients with head and neck squamous cell carcinoma (HNSCC)
• The presence of only one positive lymph node:
  • Can decrease survival by up to 50% in most HNSCC
• The risk of lymph node metastasis can be predicted in relation to:
  • Differentiation of tumor:
    • The more poorly differentiated the tumor:
      • The greater the risk
  • To the size and depth of the invasion (DOI)
  • The availability of capillary lymphatics
• The risk of lymphatic spread:
  • Increases with tumor recurrence
• Embryologically:
  • The lymphatic system is formed:
    • From its germination from the venous system:
      • Explaining the close anatomical relationship between these two systems
  • Blood capillaries have tight endothelial junctions:
    • That normally do not reabsorb larger molecules and cells
  • However, lymphatic capillaries have relatively open endothelial junctions:
    • That allow molecules and larger cells to be more easily reabsorbed:
      • Explaining the reason for easier lymphatic than vascular propensity
• The lymphatic system of the head and neck:
  • Is the region of the body composed by more lymphatic capillaries, lymphatic trunks and lymph nodes:
    • Epithelium, bone and cartilage:
      • Are devoid of lymphatic capillaries:
        • While a small minority is found in the periosteum and perichondrium
• Lymph node arrangement is archetypal and each group receives drainage (directly or indirectly) from specific areas:
  • In a deep cervical group (a terminal group for the head and region of the neck) before finally flowing into the lymphatic duct (right) / thoracic duct (left) in the jugular-subclavian junction
• Due to the absence of lymphatic vessels in the epithelium:
  • The tumor must penetrate the lamina propria before lymphatic invasion
• In the superficial layer:
  • The diameter of lymphatic capillaries is usually narrower than it is in the deeper layer
• The richness of the capillary network in each subsite can increase the relative incidence of lymph node metastases:
  • The nasopharynx, pyriform sinus (hypopharynx), supraglottic larynx and oropharynx:
    • Have the most profitable network of capillary lymphatic vessels:
      • Which is the clinical reflection of the potential presence of neoplastic lymph nodes
  • Paranasal sinuses, middle ear and vocal folds:
    • Have few or no capillary lymphatics:
      • Which is consistent with the low rate of lymph node metastases when the tumor is confined to these sites
• The involvement of lymph nodes usually follows an ordered progression and, rarely, skip nodal metastasis is revealed (exception lateral ventral tongue)
• Well lateralized lesions:
  • Determine ipsilateral lymph node metastases
• Lesions near the midline or lateral margin of tongue or nasopharyngeal lesions:
  • Can also spread contra-laterally or bilaterally:
    • But generally, tend to spread from the side of the lesion
• Patients with ipsilateral tumor nodal disease are at risk of contralateral disease:
  • Especially if the lymph node exceeds a certain size or if multiple lymph nodes are involved
• Obstruction of lymphatic pathways:
  • Caused by surgery or radiation therapy:
    • Can divert lymphatic flow on the opposite side of the neck:
      • Through anastomotic channels
• Finally, it should be remembered that metastases in cervical-cephalic regions:
  • Occur in approximately 10% of patients as neoplastic metastases from unknown primary sites
  • The histopathology of these metastases is generally referable to squamous cell carcinomas in various degrees of differentiation:
    • But metastases of adenocarcinomas, melanomas, or anaplastic tumors can also be found
  • The lymph node level is indicative of possible neoplastic origin
• Distant metastasis (DM):
  • In the absence of nodal metastasis is very rare in HNSCC
  • Untreated occult disease in the lymphatic venous system:
    • Can produce DM while the lymph node is growing
  • Patients with advanced disease have a high incidence of DM:
    • Particularly in the presence of jugular vein invasion or extensive soft tissue disease in the neck:
      • The rate of DM increases by:
        • Up to 25% to 30% for N3 disease compared to 18% to 20% for N2 disease

Thyroid Cancer Staging (Simplified for Patients)

Staging describes how far a cancer has spread. In thyroid cancer, staging helps guide treatment intensity and follow-up, but it’s important to know that most patients do very well regardless of stage.

🧠 What factors are used to stage thyroid cancer?

The AJCC staging system considers:

Tumor size and whether it extends beyond the thyroid Lymph node involvement in the neck Distant spread (lungs or bones—uncommon) Age (patients under 55 are staged differently and typically have an excellent prognosis)

📊 What do the stages mean?

Stage I–II: ✔️ Most common ✔️ Often confined to the thyroid or nearby lymph nodes ✔️ Excellent long-term survival Stage III–IV: ✔️ Less common ✔️ More extensive local disease or distant spread ✔️ Still often highly treatable with modern, multidisciplinary care

⚖️ A key clarification for patients

Stage is not the same as risk of recurrence.

We also use ATA risk stratification to estimate the chance of the cancer returning and to tailor:

Extent of surgery Use of radioactive iodine Intensity of follow-up

🦋 Why this matters

Staging helps us:

Avoid overtreatment in low-risk patients Focus resources on patients who truly need more intensive therapy Provide accurate reassurance and individualized care

👨‍⚕️ Dr. Rodrigo Arrangoiz, MD

Surgical Oncologist – Thyroid, Head & Neck, Breast

Mount Sinai Medical Center

📌 Take-home message:

In thyroid cancer, stage helps guide care—but prognosis is excellent for the vast majority of patients.

📚 References

AJCC Cancer Staging Manual, 8th Edition Haugen BR et al. ATA Guidelines for Differentiated Thyroid Cancer. Thyroid Tuttle RM et al. Risk-adapted management of thyroid cancer. Lancet Diabetes Endocrinol