The Curbsiders Internal Medicine Podcast

Episode #470: Thyroid Nodules and Thyroid Cancer for Primary Care

Release Date: February 10, 2025
Guests: Dr. Kaniksha Desai (Stanford University) & Dr. Ana Chindris (Mayo Clinic Florida)

Overview

In this episode, Drs. Matthew Watto and Paul Williams interview thyroid experts Dr. Kaniksha Desai (Stanford) and Dr. Ana Chindris (Mayo Clinic Florida) about the evaluation and management of thyroid nodules and thyroid cancer in the primary care setting. They cover updated approaches to incidental thyroid nodules, the workup process, risk stratification, interpreting imaging and biopsy findings, recent shifts in thyroid cancer management, and how to address new controversies—such as the use of GLP-1 agonists in patients with a thyroid cancer history. The conversation balances practical takeaways with up-to-date evidence and expert insights, aiming to empower primary care clinicians.

Meet the Guests [03:25–08:46]

• Dr. Kaniksha Desai: Endocrinologist, Stanford University; specializes in thyroid nodules & cancer, board certified in neck ultrasonography.
• Dr. Ana Chindris: Endocrinologist, Mayo Clinic Florida; focus on thyroid neoplasia; treasurer, Florida Endocrine Association; researcher and orchid enthusiast.

Memorable Moment:

• Dr. Chindris discusses her passion for Formula 1 racing since medical school — and vanda orchids.
• Dr. Desai shares key career advice:

  "Take the best of what everybody has to offer and then create your own style... keep an open mind about what's possible. Nothing is impossible." [06:49]

Case 1: Evaluating an Incidental Thyroid Nodule [08:55–23:25]

Scenario

• 68-year-old male (“Mr. Ty Rad”) with thyroid nodules found incidentally on lung cancer screening CT.

Initial Approach

• Incidental thyroid nodules are highly common. Most are benign, especially as age increases.
• Start with two key questions:
  • Is the nodule benign or malignant?
  • Is the nodule causing symptoms?

History & Exam Points

• Ask about:
  • Family history of thyroid cancer
  • Personal history of childhood or whole-body radiation (esp. Chernobyl exposure, bone marrow transplant)
  • Local symptoms: neck tightness, dysphagia (solids > liquids), breathing difficulty (esp. supine)
  • Subtle symptoms of hyperthyroidism (e.g., personality change, palpitations, heat intolerance)
  • Examine for palpable mass, cervical lymphadenopathy, tracheal deviation
• Physical Exam Pearls:
  • It’s normal to not palpate nodules <1 cm or posterior ones, even if ultrasound sees them
  • Styles vary: behind the patient (classic), but “there are many different styles.” — Dr. Desai [21:10]
  • Tip: “Just tell the patient you’re going to be grabbing their neck…” [22:17]

TSH and Imaging

• TSH is sensitive; if borderline low, monitor for developing hyperthyroidism (can fluctuate)
• Ultrasound is the gold standard and should be obtained for all new nodules
• Nuclear medicine scans (radionuclide) are rarely needed except for workup of overtly hyperfunctional (toxic) nodules, or when surgery is considered for a toxic nodule [23:25–28:33]

“I personally order an ultrasound in everybody.” – Dr. Chindris [23:25]

Laboratory Workup and Special Tests [28:33–34:01]

Typical Labs

• TSH is usually sufficient unless hyperthyroidism is suspected; T4/T3 rarely needed if TSH normal.
• Calcitonin: Only order if there’s a strong suspicion for medullary thyroid cancer (family history, RET mutations, men2 syndrome) — not part of routine workup.

“There has to be a really good reason for me to order a calcitonin...I’m a less is more kind of person.” – Dr. Desai [33:43]

Special note: Molecular testing can sometimes detect medullary features overlooked by cytology.

Interpreting Ultrasound: TIRADS and Red Flags [34:01–38:16]

• TIRADS: Systematic risk stratification based on ultrasound features (like BI-RADS for breast).
  • TIRADS 1: normal; 2: benign; 3: probably benign; 4a/b: indeterminate; 5: suspicious.
• Suspicious features:
  • Irregular shape or margins
  • Calcifications/microcalcifications
  • Abnormal cervical lymph nodes (“cancer until proven otherwise” — Dr. Desai [35:53])
• Make sure your ultrasound order asks to “include cervical lymph nodes.”

Follow-up Intervals

• If benign nodule shows no significant change for >5 years, can usually stop ultrasound follow-up.
• Patient anxiety commonly drives over-testing — lengthen interval if possible. [38:16]

“If a nodule has not changed after five years, you can stop.” – Dr. Chindris [38:16]

Fine Needle Aspiration (FNA) and Bethesda System [41:58–47:50]

• Bethesda Classification:
  • I: Nondiagnostic
  • II: Benign (<2% malignancy)
  • III: Atypia of undetermined significance (AUS)
  • IV: Follicular neoplasm/oncocytic
  • V: Suspicious for malignancy
  • VI: Malignant
• Indeterminate results (III/IV):
  • Now often followed with molecular testing (reflexed from FNA sample)
  • Molecular results help risk-stratify further (e.g., certain mutations → higher risk)

“Molecular testing...does not tell us if it’s cancer...but if your molecular testing is positive, we have to take it out to see if it’s cancer or not.” – Dr. Desai [47:17]

Minimally Invasive Treatments for Benign Nodules [48:27–52:28]

• Alcohol Sclerosis: For large, fluid-filled (cystic) nodules—aspirate and inject alcohol to prevent recurrence
• Ablation (Laser/Radiofrequency): Outpatient, for benign solid nodules or shrinking functionally toxic ones; no anesthesia required
• For small biopsy-proven papillary thyroid cancers: experimental ablation techniques (radiofrequency) may be used in select cases.

Case 2: Thyroid Cancer Subtypes and Modern Management [52:28–69:29]

Case Scenario

• Woman with a palpable right thyroid mass → AUS on FNA → right lobectomy → pathology reveals papillary carcinoma → completion thyroidectomy.

Subtypes of Thyroid Cancer [53:23–62:20]

• Three Major Bins:
  1. Well-Differentiated (Follicular Origin)
     • Papillary (80%)
     • Follicular (10–15%)
     • Oncocytic (Hürthle cell; 2–3%; recently separated)
  2. Medullary (C cells; MEN2, RET mutations)
  3. Anaplastic (Undifferentiated, aggressive, universally stage IV)
• Papillary: “This is the one that has a five-year survival rate of like 99%.” [54:01]
• Anaplastic: “Everybody in that category is actually stage four on presentation, and a five-year life expectancy is pretty poor. It's like less than 10%.” – Dr. Desai [57:10]

Management Paradigm Shifts [54:01–62:20]

• Less aggressive: More hemithyroidectomies (hemi only), less radioactive iodine, less TSH suppression
• Total thyroidectomy plus radioactive iodine and suppression now reserved for higher-risk cases
• Pathologic risk stratification based on:
  • Lymph node involvement
  • Tumor size
  • Extra-thyroidal extension
  • Variant histology (e.g., tall cell variant)
  • Distant metastases
• Age under 55 = better outcomes, influences staging

Primary Care Follow-Up and Survivorship [64:08–70:43]

Follow-up after Cancer:

• For most well-differentiated thyroid cancers:
  • Annual TSH and thyroglobulin (if total thyroidectomy)
  • Periodic neck ultrasound (most closely spaced after diagnosis, intervals may be lengthened)
  • If patient has only hemithyroidectomy, thyroglobulin monitoring is not useful — will be detectable
  • If patients drop out of endocrinology care: seek to clarify cancer subtype, surgery, therapies received

TSH Goals:

• For hemi-thyroidectomy: most don’t need lifelong levothyroxine; TSH goal is normal range, not <2.0 as in old practice.

GLP-1 Agonists and Thyroid Cancer (Semaglutide, Tirzepatide, etc.) [70:49–78:42]

Key Question: Should you avoid GLP-1s for weight loss in someone with thyroid cancer history?

• Concern comes from early rodent studies of medullary thyroid cancer risk.
• Recent population studies (2023+) have not confirmed a significant risk for most thyroid cancer types.
• Major contraindication: Medullary thyroid cancer or MEN2 (multiple family members, RET mutation, pheochromocytoma).
• Papillary/Follicular (well-differentiated): GLP-1s considered safe and reasonable.
• Don’t routinely ultrasound the thyroid before starting GLP-1s unless there’s a nodule or concerning family/personal history.

  “If the answer is, ‘Yeah, I knew my family member got radioactive iodine, then there’s zero chance it was medullary.’” – Dr. Desai [73:32]

• Both endocrinologists use GLP-1 agonists in thyroid cancer survivors if not medullary/anaplastic.

Memorable Quotes

“Thyroid nodules are very common...The incidence increases with age, and the vast majority of them are benign. These are the three points that I tell them.” — Dr. Chindris [09:52]

“There is no good cancer. So for anybody who says that, don’t ever say that, everybody’s journey is a little bit different.” — Dr. Desai [53:41]

“Current paradigm in thyroid cancer is really considering what the long term side effects of treatment...less is more category.” — Dr. Desai [79:24]

“Ultrasound is the gold standard…in most cases it’s going to tell you what to do.” – Dr. Chindris [81:40]

Take-Home Pearls [78:58–81:40]

Dr. Ana Chindris (Thyroid Nodules):

• Most thyroid nodules are benign — reassure patients.
• Ultrasound is the gold standard for nodule evaluation.
• Be aware of molecular testing as an option after indeterminate cytology.

Dr. Kaniksha Desai (Thyroid Cancer):

• Cancer is never “good” — each journey is unique; acknowledge patients’ anxiety.
• “Less is more” in modern thyroid cancer care: more hemithyroidectomies, less radioiodine and suppression.
• For GLP-1 agonists: weigh overall benefits; avoid only in clear medullary thyroid cancer or MEN2.

Timestamps for Key Segments

• [08:55] Initial approach to incidental thyroid nodules
• [17:59] Local and systemic symptoms of nodules
• [23:25] Imaging: Ultrasound vs. radionuclide scan
• [28:55] Labs and role of calcitonin
• [34:01] TIRADS and ultrasound features
• [41:58] Fine needle aspiration & Bethesda categories
• [48:27] Ablation and minimally invasive procedures
• [53:23] Thyroid cancer subtypes and paradigm shifts
• [62:43] Risk stratification in well-differentiated thyroid cancer
• [64:08] Primary care follow-up and survivorship
• [70:49] GLP-1 agonists and thyroid cancer risk
• [78:58] Take-home points from both experts

Useful for Listeners:

• Confidently approach incidental thyroid nodules, know what to ask and how to examine.
• Understand when and why you may order imaging or further tests (and when not to).
• Clarify how to interpret and act on fine needle aspiration results.
• Recognize that most thyroid cancers, especially papillary, have excellent prognosis — and management can be conservative.
• Know when and how to use GLP-1 RA for obesity/diabetes after thyroid cancer, and what questions to ask about patient history.
• Reassure patients, minimize anxiety and overtreatment, and collaborate with specialists when needed.

End of summary.