These guidelines aim to establish the standard practice for diagnosing and treating patients with differentiated thyroid cancer (DTC). Based on the Korean Thyroid Association (KTA) Guidelines on DTC management, the “Treatment of Advanced DTC” section was revised in 2024 and has been provided through this chapter. Especially, this chapter covers surgical and nonsurgical treatments for the local (previous surgery site) or regional (cervical lymph node metastasis) recurrences. After drafting the guidelines, it was finalized by collecting opinions from KTA members and related societies. Surgical resection is the preferred treatment for local or regional recurrence of advanced DTC. If surgical resection is not possible, nonsurgical resection treatment under ultrasonography guidance may be considered as an alternative treatment for local or regional recurrence of DTC. Furthermore, if residual lesions are suspected even after surgical resection or respiratory-digestive organ invasion, additional radioactive iodine and external radiation treatments are considered.

Pediatric differentiated thyroid cancers (DTCs), mostly papillary thyroid cancer (PTC, 80-90%), are diagnosed at more advanced stages with larger tumor sizes and higher rates of locoregional and/or lung metastasis. Despite the higher recurrence rates of pediatric cancers than of adult thyroid cancers, pediatric patients demonstrate a lower mortality rate and more favorable prognosis. Considering the more advanced stage at diagnosis in pediatric patients, preoperative evaluation is crucial to determine the extent of surgery required. Furthermore, if hereditary tumor syndrome is suspected, genetic testing is required. Recommendations for pediatric DTCs focus on the surgical principles, radioiodine therapy according to the postoperative risk level, treatment and follow-up of recurrent or persistent diseases, and treatment of patients with radioiodine-refractory PTCs on the basis of genetic drivers that are unique to pediatric patients.

Differentiated thyroid cancer demonstrates a wide range of clinical presentations, from very indolent cases to those with an aggressive prognosis. Therefore, diagnosing and treating each cancer appropriately based on its risk status is important. The Korean Thyroid Association (KTA) has provided and amended the clinical guidelines for thyroid cancer management since 2007. The main changes in this revised 2024 guideline include 1) individualization of surgical extent according to pathological tests and clinical findings, 2) application of active surveillance in low-risk papillary thyroid microcarcinoma, 3) indications for minimally invasive surgery, 4) adoption of World Health Organization pathological diagnostic criteria and definition of terminology in Korean, 5) update on literature evidence of recurrence risk for initial risk stratification, 6) addition of the role of molecular testing, 7) addition of definition of initial risk stratification and targeting thyroid stimulating hormone (TSH) concentrations according to ongoing risk stratification (ORS), 8) addition of treatment of perioperative hypoparathyroidism, 9) update on systemic chemotherapy, and 10) addition of treatment for pediatric patients with thyroid cancer.

The primary objective of initial treatment for thyroid cancer is minimizing treatment-related side effects and unnecessary interventions while improving patients’ overall and disease-specific survival rates, reducing the risk of disease persistence or recurrence, and conducting accurate staging and recurrence risk analysis. Appropriate surgical treatment is the most important requirement for this purpose, and additional treatments including radioactive iodine therapy and thyroid-stimulating hormone suppression therapy are performed depending on the patients’ staging and recurrence risk. Diagnostic surgery may be considered when repeated pathologic tests yield nondiagnostic results (Bethesda category 1) or atypia of unknown significance (Bethesda category 3), depending on clinical risk factors, nodule size, ultrasound findings, and patient preference. If a follicular neoplasm (Bethesda category 4) is diagnosed pathologically, surgery is the preferred option. For suspicious papillary carcinoma (suspicious for malignancy, Bethesda category 5), surgery is considered similar to a diagnosis of malignancy (Bethesda category 6). As for the extent of surgery, if the cancer is ≤1 cm in size and clinically free of extrathyroidal extension (ETE) (cT1a), without evidence of cervical lymph node (LN) metastasis (cN0), and without obvious reason to resect the contralateral lobe, a lobectomy can be performed. If the cancer is 1-2 cm in size, clinically free of ETE (cT1b), and without evidence of cervical LN metastasis (cN0), lobectomy is the preferred option. For patients with clinically evident ETE to major organs (cT4) or with cervical LN metastasis (cN1) or distant metastasis (M1), regardless of the cancer size, total thyroidectomy and complete cancer removal should be performed at the time of initial surgery. Active surveillance may be considered for adult patients diagnosed with low-risk thyroid papillary microcarcinoma. Endoscopic and robotic thyroidectomy may be performed for low-risk differentiated thyroid cancer when indicated, based on patient preference.

Conventional open thyroidectomy is a safe procedure, but it has the disadvantage of leaving noticeable scars on the neck. Bilateral axillo-breast approach (BABA) robotic thyroidectomy was developed as an alternative technique to remove thyroid glands without making incisions in the neck. In traditional BABA robotic thyroidectomy, dividing the isthmus is a routine step to improve the efficiency of the dissection during thyroid surgery. However, there are safety concerns when performing this procedure on patients with thyroid cancer located in the isthmus. We report a case of BABA robotic total thyroidectomy carried out without dividing the isthmus in a patient with isthmic papillary thyroid carcinoma. Our experience suggests that BABA robotic surgery can be a feasible and safe option for selected patients with isthmic papillary thyroid carcinoma.

Active surveillance (AS) of papillary thyroid microcarcinoma was first suggested by Dr. Akira Miyauchi at Kuma Hospital in 1993. Based on several subsequent evidences, AS was approved by the American Thyroid Association in 2015. AS is no longer an experimental treatment but has become an acceptable standard of care for patients with low-risk thyroid cancers. No molecular markers, such as BRAF mutations, have been identified to predict the prognosis of papillary thyroid cancer. However, future molecular studies may reveal the relationship between genetic mutations and thyroid cancer prognosis. AS involves closely monitoring thyroid cancer over time, instead of immediately treating it with surgery. Patients and medical doctors should consider these two options: observation or surgery.

Active surveillance (AS) of papillary thyroid microcarcinoma was first suggested by Dr. Akira Miyauchi at Kuma Hospital in 1993. Based on several subsequent evidences, AS was approved by the American Thyroid Association in 2015. AS is no longer an experimental treatment but has become an acceptable standard of care for patients with low-risk thyroid cancers. No molecular markers, such as BRAF mutations, have been identified to predict the prognosis of papillary thyroid cancer. However, future molecular studies may reveal the relationship between genetic mutations and thyroid cancer prognosis. AS involves closely monitoring thyroid cancer over time, instead of immediately treating it with surgery. Patients and medical doctors should consider these two options: observation or surgery.

PURPOSE: Routine supplementation of high-dose calcium significantly decreased the risk of postoperative symptomatic hypocalcemia after thyroidectomy. However, there is an ongoing debate about whether the same results can be achieved with low-dose calcium supplementation. METHODS: Patients (n = 138) who underwent total thyroidectomy for thyroid cancer were 1:1 randomly assigned to receive oral supplements of 1,500 mg/day elemental calcium and 1,000 IU/day cholecalciferol for 2 weeks or no supplementation. Primary objective was to compare the incidence of symptomatic hypocalcemia for 3 days after total thyroidectomy. Secondary objective was to find the predictors for postoperative hypocalcemia in patients with thyroid cancer. RESULTS: Sixty-five patients in the calcium group and 69 patients in the control group were finally analyzed. The incidence of symptomatic hypocalcemia showed no difference between the calcium and control group (32.3% vs. 21.7%, P = 0.168). The total dosage of intravenous calcium (593.4 ± 267.1 mg vs. 731.6 ± 622.7 mg, P = 0.430) administered to patients with symptomatic hypocalcemia was also comparable between groups. In a multivariate analysis, parathyroid hormone level of 13 pg/mL at postoperative day 1 was only predictive for symptomatic hypocalcemia, and its incidence was 20.9 times (95% confidence interval, 6.8–64.5) higher in patients with parathyroid hormone <13 pg/mL. Other factors did not predict the development of hypocalcemia, including clinicopathological features and routine supplementation of low-dose calcium. CONCLUSION: Routine low-dose calcium supplementation did not reduce the risk of postoperative hypocalcemia. Patients who may benefit from calcium supplementation should be carefully selected.
Calcium ; Cholecalciferol ; Humans ; Hypocalcemia ; Hypoparathyroidism ; Incidence ; Multivariate Analysis ; Parathyroid Hormone ; Prospective Studies ; Thyroid Neoplasms ; Thyroidectomy

Squamous cell carcinoma of the breast and its subtype, basal-human epidermal growth factor receptor 2 (HER2) phenotype, are very rare. Herein, we report a patient who developed recurrence of squamous cell carcinoma of the breast with basal-HER2 subtype 6 years after the initial diagnosis of invasive ductal carcinoma of the HER2 subtype. To the best of our knowledge, recurrence of invasive ductal carcinoma in the form of metaplastic squamous cell carcinoma of basal-HER2 subtype has not been reported previously. We present a pathological perspective of our experience.
Breast ; Carcinoma, Ductal ; Carcinoma, Squamous Cell ; Diagnosis ; Epidermal Growth Factor ; Humans ; Pathology ; Phenotype ; Receptor, Epidermal Growth Factor ; Recurrence

PURPOSE: Endoscopic thyroidectomy using a cervico-axillary approach (CAA) provides optimal visualization with a smaller dissection plane. Despite the excellent cosmetic results and high patient satisfaction, the surgical and oncologic safety of CAA endoscopic surgery has not been fully established. The present study evaluated the feasibility, safety, and surgical outcomes of CAA endoscopic thyroidectomy. METHODS: From October 2009 to April 2012, 100 patients with papillary thyroid cancer underwent CAA endoscopic thyroidectomy. Patient demographics, pathologic features, and surgical outcomes including complications and recurrence were collected. RESULTS: CAA endoscopic thyroidectomy was successful in all patients, and none required conversion to open thyroidectomy. All patients underwent ipsilateral thyroid lobectomy with or without central compartment neck dissection. The mean tumor size was 1.0±0.6 cm (range, 0.5~1.6), and 35.0% of tumors showed extrathyroidal extension. The mean number of harvested lymph nodes was 4.1±4.4, and metastasis was found in 12.0% of patients. The mean surgical time was 175.2±50.4 min, mean intraoperative blood loss was 42.5±69.2 ml, and the mean hospital stay was 3.3±0.6 days. There were five cases of postoperative transient hypocalcemia and eight cases of vocal cord palsy. No permanent complication or postoperative bleeding was observed. Patients continued to be seen for a median period of 63.7 months, and no recurrence of thyroid cancer was seen. CONCLUSION: CAA endoscopic thyroidectomy is a feasible and safe procedure for low-risk thyroid cancer, with excellent cosmesis. It can be recommended as an alternative option for selected patients with low-risk thyroid cancer.
Demography ; Hemorrhage ; Humans ; Hypocalcemia ; Length of Stay ; Lymph Nodes ; Neck Dissection ; Neoplasm Metastasis ; Operative Time ; Patient Satisfaction ; Recurrence ; Thyroid Gland* ; Thyroid Neoplasms* ; Thyroidectomy* ; Vocal Cord Paralysis