The increasing detection of papillary thyroid microcarcinoma (PTMC) has raised concerns about overtreatment.For low-risk PTMC, either immediate surgery or active surveillance (AS) can be considered. To support AS implementation, the Korean Thyroid Association convened a multidisciplinary panel and developed the first Korean guideline. AS is recommended to adults with pathologically proven Bethesda V-VI PTMC without clinical evidence of lymph node or distant metastasis, gross extrathyroidal extension, tracheal or recurrent laryngeal nerve invasion, or aggressive histology. Baseline assessment requires high‑resolution cervical ultrasound by experienced operators to rule out extrathyroidal extension, tracheal or recurrent laryngeal nerve invasion, and lymph node metastasis;contrast‑enhanced neck computed tomography is optional. Patient characteristics such as age, comorbidities, and capacity for long-term follow-up should be assessed. Shared decision-making should weigh the benefits and risks of surgery and AS, expected oncologic outcomes, complications, quality of life, anxiety, medical cost, and patient preference. Follow-up includes cervical ultrasound and thyroid function test every six months for two years, then annually. Disease progression, defined as significant tumor growth or newly detected nodal or distant metastasis, warrants surgery. Despite remaining uncertainties, this guideline offers a framework to ensure oncologic safety and support patient-centered active surveillance.

The indolent nature and favorable outcomes associated with papillary thyroid microcarcinoma have prompted numerous prospective studies on active surveillance (AS) and its adoption as an alternative to immediate surgery in managing low-risk thyroid cancer. This article reviews the current status of AS, as outlined in various international practice guidelines. AS is typically recommended for tumors that measure 1 cm or less in diameter and do not exhibit aggressive subtypes on cytology, extrathyroidal extension, lymph node metastasis, or distant metastasis. To determine the most appropriate candidates for AS, factors such as tumor size, location, multiplicity, and ultrasound findings are considered, along with patient characteristics like medical condition, age, and family history. Moreover, shared decision-making, which includes patient-reported outcomes such as quality of life and cost-effectiveness, is essential. During AS, patients undergo regular ultrasound examinations to monitor for signs of disease progression, including tumor growth, extrathyroidal extension, or lymph node metastasis. In conclusion, while AS is a feasible and reliable approach for managing lowrisk thyroid cancer, it requires careful patient selection, effective communication for shared decision-making, standardized follow-up protocols, and a clear definition of disease progression.

The American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging classification of thyroid cancer can predict death but cannot determine the type and frequency of follow-up testing. Risk stratification is a concept proposed by the American Thyroid Association that uses additional prognostic factors that are not included in the AJCC/UICC classification, such as number or size of metastatic lymph nodes, genetic mutations, and vascular invasion in follicular cancer, to further refine the prognosis of thyroid cancer. The risk of recurrence was categorized as low, intermediate, and high risk, and the need for total thyroidectomy, radioiodine therapy, or thyroid-stimulating hormone suppression was determined depending on each risk level. This approach has been accepted worldwide, and the previous recommendations of the Korean Thyroid Association followed a similar line of thinking but these have been modified in the revised 2024 guidelines.For the revised initial risk stratification, after careful review of the results of the recent meta-analyses and large observational studies and after a multidisciplinary meeting, four major changes were made: 1) thyroid cancer was reclassified according to the World Health Organization (WHO) 2022 tumor classification system; 2) recurrence risk was stratified by combining encapsulated follicular variant papillary thyroid cancer, follicular thyroid cancer, and oncocytic thyroid cancer, which have similar recurrence risk and associated factors, into follicular-patterned tumor; 3) low-risk groups were defined as those with a known recurrence rate of ≤5%, high-risk groups were upgraded to those with a known recurrence rate of ≥30%, and intermediate-risk groups were those with a recurrence risk of 5–30%; and 4) the intermediate risk group had the recurrence rate presented according to various clinicopathological factors, mainly based on reports from Korea. Thus, it is recommended to evaluate the initial risk group by predicting the recurrence rate by combining each clinical factor in individual patients, rather than applying the recurrence rate caused by single risk factor.

Only a small percentage of patients (2-5%) with differentiated thyroid cancer (DTC) exhibit distant metastasis at the initial diagnosis or during the disease course. The most common metastatic sites of DTC are the lungs, followed by the bones. Radioactive iodine (RAI) therapy is considered the primary treatment for RAI-avid distant metastatic DTC. Depending on the characteristics of metastatic lesions, local treatment such as surgical resection, radiofrequency ablation, and external beam radiation therapy may be considered for some patients with metastatic DTC. Slowly growing and asymptomatic metastases can be monitored with follow-up while receiving thyroid-stimulating hormone (TSH) suppression therapy. In patients with a limited number of lung metastases and good performance status, surgical removal of the metastatic lesions may be considered. Systemic therapy should be considered for patients with progressive RAI refractory DTC. In this clinical guideline, we aim to outline the treatment principles for patients with lung, bone, and brain metastases of DTC.

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.

Background: Thyroid cancer screening has contributed to the skyrocketing prevalence of thyroid cancer. However, the true benefit of thyroid cancer screening is not fully understood. This study aimed to evaluate the impact of screening on the clinical outcomes of thyroid cancer by comparing incidental thyroid cancer (ITC) with non-incidental thyroid cancer (NITC) through a meta-analysis. Methods: PubMed and Embase were searched from inception to September 2022. We estimated and compared the prevalence of high-risk features (aggressive histology of thyroid cancer, extrathyroidal extension, metastasis to regional lymph nodes or distant organs, and advanced tumor-node-metastasis [TNM] stage), thyroid cancer-specific death, and recurrence in the ITC and NITC groups. We also calculated pooled risks and 95% confidence intervals (CIs) of the outcomes derived from these two groups. Results: From 1,078 studies screened, 14 were included. In comparison to NITC, the ITC group had a lower incidence of aggressive histology (odds ratio [OR], 0.46; 95% CI, 0.31 to 0.7), smaller tumors (mean difference, −7.9 mm; 95% CI, −10.2 to −5.6), lymph node metastasis (OR, 0.64; 95% CI, 0.48 to 0.86), and distant metastasis (OR, 0.42; 95% CI, 0.23 to 0.77). The risks of recurrence and thyroid cancer-specific mortality were also lower in the ITC group (OR, 0.42; 95% CI, 0.25 to 0.71 and OR, 0.46; 95% CI, 0.28 to 0.74) than in the NITC group. Conclusion Our findings provide important evidence of a survival benefit from the early detection of thyroid cancer compared to symptomatic thyroid cancer.

Background/Aims: This study evaluated the long-term cardiovascular complications among Korean patients with hypertension and compared them with that of controls without hypertension. Methods: The Korean Hypertension Cohort (KHC) enrolled 11,043 patients with hypertension and followed them for more than 10 years. Age- and sex-matched controls without hypertension were enrolled at a 1:10 ratio. We compared the incidence of cardiovascular events and death among patients and controls without hypertension. Results: The mean age was 59 years, and 34.8% and 16.5% of the patients belonged to the high and moderate cardiovascular risk groups, respectively. During the 10-year follow-up, 1,591 cardiovascular events (14.4%) with 588 deaths (5.3%) occurred among patients with hypertension and 7,635 cardiovascular events (6.9%) with 4,826 deaths (4.4%) occurred among controls. Even the low-risk population with hypertension showed a higher cardiovascular event rate than the population without hypertension. Although blood pressure measurements in the clinic showed remarkable inaccuracy compared with those measured in the national health examinations, systolic blood pressure (SBP) ≥ 150 mmHg was significantly associated with a higher risk of cardiovascular events. Conclusions This long-term follow-up study confirmed the cardiovascular event rates among Korean hypertensive patients were substantial, reaching 15% in 10 years. SBP levels ≥ 150 mmHg were highly associated with occurrence of cardiovascular event rates.

Background/Aims: There have been few multicenter studies on colonic polyps conducted by primary medical institutions. This study examined the detection rate of colonic polyps in primary health care institutions and the related factors while following the guidelines. Methods: The medical records of 14,029 patients who underwent colonoscopy between January-June 2020 at 40 primary medical institutions in Korea were analyzed. High-risk adenoma was defined as advanced adenoma, carcinoma, or ≥3 adenomas. Results: Most patients (71.2%) aged ≥50 years underwent re-colonoscopy within 5 years (51.3%) for diagnostic purposes (61.3%) in Korean primary medical institutions. The detection rates of colon polyps, adenoma, advanced adenoma, high-risk adenoma, and carcinoma was 59.9%, 38.9%, 5.9%, 11.4%, and 0.3% in all subjects and 59.8%, 37.5%, 8.5%, 12.9%, and 0.3% in average-risk patients, respectively. The incidences of adenoma in average-risk patients increased significantly with age (30s/40s/50s: 20.1%/29.4%/43% for adenoma, 4.4%/6.7%/10.3% for advanced adenoma, and 5.6%/9.5%/14.6% for high-risk adenoma; p<0.05). Before 50 years of age, high-risk adenoma was detected in 9.1% of patients in the first-time screening group, and the significant risk factors were being male and ≥40 years of age. The detection rate of high-risk adenoma in the normal index colonoscopy group within 5 years was 9.0%. The significant risk factors included older age, male sex, positive fecal occult blood test, stool form changes, and nonspecific symptoms (gas and indigestion). Conclusions More colonic adenoma studies targeting real-world clinical practice will be needed to revise the Korean guidelines for colorectal cancer screening and surveillance.

Purpose: At the end of life, communication is a key factor for good care. However, in clinical practice, it is difficult to adequately discuss end-of-life care. In order to understand and analyze how decision-making related to life-sustaining treatment (LST) is performed, the shared decision-making (SDM) behaviors of physicians were investigated. Methods: A questionnaire was designed after reviewing the literature on attitudes toward SDM or decision-making related to LST. A final item was added after consulting experts. The survey was completed by internal medicine residents and hematologists/medical oncologists who treat terminal cancer patients. Results: In total, 202 respondents completed the questionnaire, and 88.6% said that the decision to continue or end LST is usually a result of SDM since they believed that sufficient explanation is provided to patients and caregivers, patients and caregivers make their own decisions according to their values, and there is sufficient time for patients and caregivers to make a decision. Expected satisfaction with the decisionmaking process was the highest for caregivers (57.4%), followed by physicians (49.5%) and patients (41.1%). In total, 38.1% of respondents said that SDM was adequately practiced when making decisions related to LST. The most common reason for inadequate SDM was time pressure (89.6%). Conclusion Although most physicians answered that they practiced SDM when making decisions regarding LST, satisfactory SDM is rarely practiced in the clinical field. A model for the proper implementation of SDM is needed, and additional studies must be conducted to develop an SDM model in collaboration with other academic organizations.