Diagnosis
Thyroid cancer
Malignancy arising from the thyroid parenchymal cells.
Etiology
Cause [b5y]
Genetic: familial occurrence of thyroid cancer is approximately 5%
Sporadic: mutations and translocations in BRAF mutant kinase, proto-oncogenes, and p53 tumor suppressor gene
Pathophysiology [b5y]
Clinical presentation:
Neck swelling
Lymphadenopathy
Pressure symptoms: hoarseness, dysphagia, dyspnea, or Horner's Syndrome
Systemic symptoms: weight loss and fatigue
Classification [p5t][b5y]
Follicular cells -> Differentiated papillary/follicular cancer (95%): good prognosis
Parafollicular or C-cells -> Undifferentiated: medullary and anaplastic (3%)
Risk factors [b5y]
Female sex
Family history of thyroid cancer
Radiation exposure
Complications [b5y]
Local invasion into the airway, esophagus, or other nearby neurovascular structures
Distant metastasis ( lung, bone, and other soft tissue structures
Complications to surgery: neurovascular injury (recurrent laryngeal nerve)
Epidemiology
Incidence per 100.000 [p5t][rig][pop][ymf][vkv]
Symptoms & findings
Symptoms
Dysphagia, Dysphonia, Dyspnea, Hoarseness, Lymphadenopathy
Clinical findings
None listed.
Anamneses
None listed.
Localized findings
Approach
Blood test
FNAC:
Negative --> ultrasound collum to diffrentiate nodule from cyst
Nondagnostic: Radio-Iodine to differentiate "hot" (1% malignant) from "cold" (15-20% malignant)
Positive: CT collum and MR collum --> surgery
Treatment
Total thyroidectomy: [p5t][b5y]
Tumor size > 4 cm
Lymph node involvement --> lymph node dissection
Distant metastases
Extrathyroidal extension
Thyroid lobectomy or total thyroidectomy:
Tumor size 1-4 cm
No extrathyroidal extension / lymph node involvement
Thyroid lobectomy:
Tumor size < 1 cm
Radioactive iodine:
Residual remnant ablation
Metastatic thyroid cancer treatment
Postoperative thyroid hormone suppression therapy to minimize thyroid cancer growth
Chemotherapy: carefully selected patients with a high or rapidly progressive metastatic disease burden
Differential diagnoses
Carotid aneurism, Lymphadenopathy, Thyroglossal duct cyst, Thyroid lymphoma, Toxic nodular goiter, Toxic thyroid adenoma, Tularemia
References
[1] Lee K, Anastasopoulou C, Chandran C, et al. Thyroid Cancer. Updated 2023 May 1]: https://www.ncbi.nlm.nih.gov/books/NBK459299/
[2] Shank JB, Are C, Wenos CD. Thyroid Cancer: Global Burden and Trends. Indian J Surg Oncol. 2022 Mar;13(1):40-45.
[3] Du L, Zhao Z, Zheng R, Li H, Zhang S, Li R, Wei W, He J. Epidemiology of Thyroid Cancer: Incidence and Mortality in China, 2015. Front Oncol. 2020 Nov 10;10:1702.
[4] https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/thyroid-cancer/incidence#heading-One
[5] Ellison LF, Bushnik T. Changing trends in thyroid cancer incidence in Canada: A histologic examination, 1992 to 2016. Health Rep. 2020 Jan 15;31(1):15-25.
[6] Horn-Ross PL, McClure LA, Chang ET, Clarke CA, Keegan TH, Rull RP, Quach T, Gomez SL. Papillary thyroid cancer incidence rates vary significantly by birthplace in Asian American women. Cancer Causes Control. 2011 Mar;22(3):479-85.
[7] [First Aid for the Surgery Clerkship]