an overview on thyroid cancer and approach to it.pptx

an overview on thyroid cancer

1. An overview on thyroid cancer

2. Epidemiology Incidence: ∼ 13.5 new cases per 100,000 per year
Sex Differentiated carcinoma (papillary and follicular): ♀ > ♂ (3:1)
Poorly-differentiated carcinoma (medullary and anaplastic): ♀ ≈ ♂

3. Etiology Genetic factors Medullary carcinoma: associated with MEN2 (RET gene mutations) or familial medullary carcinoma Papillary carcinoma: associated with RET/PTC rearrangements and BRAF mutations Follicular carcinoma: associated with PAX8-PPAR-γ rearrangement and RAS mutation Undifferentiated/anaplastic carcinoma: associated with TP53 mutation Ionizing radiation (particularly during childhood): mostly associated with papillary carcinoma

4. Subtypes and variants Hurthle cell carcinoma 3–10% of all well-differentiated thyroid cancers Often classified as subtype of follicular carcinoma B-cell lymphoma: usually develops from Hashimoto thyroiditis
Sarcoma: rare
Metastatic (e.g., breast, renal, melanoma): rare

5. Clinical features Thyroid carcinoma may be asymptomatic (e.g., thyroid incidentaloma ) or manifest with any or all of the following clinical features: Thyroid nodule
Firm to hard consistency
Typically painless
Features of local infiltration or compression
Fixed thyroid nodule
Recent onset of any of the following: Hoarseness of voice (vocal cord paresis) Dyspnea Dysphagia
Horner syndrome (rare)
Venous obstruction (very rare): IJV thrombosis, SVC syndrome

6. Clinical features 7. Painless cervical lymphadenopathy More common in papillary thyroid cancer and anaplastic thyroid cancer Less common in follicular thyroid cancer 8. Signs of distant metastasis More common in follicular thyroid cancer and anaplastic thyroid cancer Less common in papillary thyroid cancer Examples include:
Pulmonary metastases: coughing, hemoptysis , dyspnea Bone metastases: bone pain, pathologic fractures
Brain metastases: focal neurologic deficit, seizures
Paraneoplastic syndrome: diarrhea and facial flushing (typically seen in advanced medullary carcinoma)

7. Approach For initial evaluation, follow the diagnostic approach to thyroid nodules. TSH, ultrasound, potentially scintigraphy Confirmation: fine-needle aspiration cytology (FNAC) or intraoperative frozen-section
Thyroid tumor markers help to estimate the prognosis and assess response to therapy.
Differentiated thyroid cancer: serum thyroglobulin ( Tg )
Medullary carcinoma: serum calcitonin and carcinoembryonic antigen (CEA) Staging of lymph node and distant metastases
Patients with medullary carcinoma require further assessment.
Genetic testing for RET germline mutations
Screening of family members
Screening for associated conditions (e.g., MEN2)

8. Initial evaluation Laboratory studies and ultrasound Serum TSH and ultrasound should be obtained in all patients with thyroid nodules.
TSH: typically normal or mildly elevated Thyroid ultrasound: to assess for sonographic signs of thyroid malignancy: Solid or mostly solid hypoechoic nodule(s)
Irregular margins Microcalcifications within nodules
Nodules that are taller than wide Extrathyroidal growth

9. Thyroid scintigraphy Indications Thyroid nodule(s) with ↓ TSH levels
Multinodular thyroids (to identify nodules that require FNAC)
Prior to RAIA to evaluate eligibility for adjuvant treatment of well-differentiated thyroid cancer Contraindications : pregnant and breastfeeding women Supportive findings : decreased or no radiotracer uptake (i.e., hypofunctioning or nonfunctioning nodules, referred to as cold nodules

10. Confirmatory tests Fine-needle aspiration cytology (FNAC) Indications : sonographic signs of thyroid cancer detected on thyroid ultrasound Supportive findings : typically reported as “malignant” or “suspicious for malignancy” according to the Bethesda system for thyroid cytopathology 2. Intraoperative frozen-section: Consider if FNAC cannot reliably rule out malignancy in high-risk patients.

11. Differential diagnoses Thyroid cyst Ultrasound findings:
Anechoic round mass
In many cases, dorsal acoustic enhancement
Relatively frequent and typically harmless

12. Treatment Well-differentiated thyroid cancer Standard management (regardless of nodal or distant metastases): total thyroidectomy (with neck dissection as needed) + RAIA + TSH suppression therapy
Small cancers without nodal or distant metastases: Consider hemithyroidectomy + TSH suppression therapy.
Papillary microcarcinoma in low-risk patients : Consider active surveillance.

13. Treatment Poorly-differentiated thyroid cancer Medullary carcinoma : total thyroidectomy + neck dissection ± radiation therapy and/or systemic chemotherapy as needed. Anaplastic carcinoma: Resectable cancer: total thyroidectomy + neck dissection + radiochemotherapy Unresectable or metastatic cancer: palliative care

14. Surgery Surgical resection is the primary treatment for thyroid cancer. Total thyroidectomy Indications Well-differentiated thyroid carcinoma Tumor size ≥ 4 cm Tumor size 1–4 cm (individual decision)
With/without extrathyroidal extension
With/without nodal or distant metastases
Medullary carcinoma Resectable anaplastic thyroid cancer

15. Considerations Total thyroidectomy should be combined with neck dissection as needed (e.g., in patients with regional lymph node spread). Thyroid hormone replacement is required in all patients who undergo total thyroidectomy.
Maintain TSH within the physiological range for poorly-differentiated thyroid cancer.
TSH-suppressive therapy is required for well-differentiated thyroid cancer.

16. Hemithyroidectomy Indications Small, well-differentiated thyroid carcinoma with all of the following characteristics: Intrathyroidal tumors (i.e., no evidence of extrathyroidal extension)
No nodal or distant metastasis
No high-risk patient factors such as age > 45 years, history of head and neck radiation, or family history of cancer
Preferred option in tumors < 1 cm in size with all of the above characteristics
An alternative to total thyroidectomy in tumors 1–4 cm in size with all of the above characteristics

17. Hemithyroidectomy Contraindications Intrathyroidal tumor ≥ 4 cm Extrathyroidal spread
Distant or nodal metastasis
High-risk patient factors

18. Complications Hypocalcemia : as a result of accidental removal of parathyroid glands Dysphonia (hoarseness) and/or dysphagia : as a result of transection of the superior and recurrent laryngeal nerve May occur during ligation of the superior laryngeal artery and inferior thyroid artery due to the proximity of the nerves to the arteries
If only the external branch of the superior laryngeal nerve is damaged, complete loss of the voice is unlikely, but a loss of vocal range may occur (with potentially career-damaging consequences for, e.g., singers and actors).
Vocal cord function should be assessed preoperatively with laryngoscopy.

19. Follow-up Physical examination
Biochemical tests E.g., tumor markers such as thyroglobulin for differentiated thyroid cancers Neck ultrasound
Further imaging, if a relapse is suspected E.g., iodine-123 or iodine-131scintigraphy in papillary/follicular malignancies while pausing thyroid hormone therapy

20. Prognosis