Janus kinase (JAK) inhibitors are an important treatment option for ulcerative colitis, providing rapid onset of action, oral administration, and efficacy even after biologic failure. The 3 approved agents—tofacitinib, filgotinib, and upadacitinib—differ in JAK isoform selectivity, leading to clinically meaningful differences in efficacy and safety. Evidence from network meta-analyses, clinical trials, and real-world studies consistently shows that upadacitinib provides the highest efficacy for induction and maintenance of remission, whereas filgotinib demonstrates the most favorable safety profile. The strong efficacy of upadacitinib and tofacitinib is particularly relevant in patients with severe disease, including acute severe ulcerative colitis, and upadacitinib maintains high efficacy regardless of prior advanced therapy exposure. JAK inhibitors also benefit extraintestinal manifestations. Although risks such as herpes zoster, serious infection, thromboembolism, and major cardiovascular events differ among agents, long-term data suggest generally acceptable safety when used appropriately. Intraclass JAK-to-JAK cycling is feasible, with about half of patients achieving steroid-free clinical remission in retrospective cohorts. Based on mechanistic, clinical, and real-world evidence, filgotinib may be a first-line option for patients with lower disease activity or when safety is a priority, whereas upadacitinib or tofacitinib may be preferred in higher disease activity. Strategically selecting agents may improve durability and outcomes.

In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.

The efficacy of clarithromycin-containing triple therapy (TT) against Helicobacter pylori has declined in Korea, with recent first-line eradication rates falling below 70%. Clarithromycin resistance exceeded 30%, undermining the standard regimen for H. pylori. These trends necessitate a change in the treatment strategy. This review analyzed the shift proposed in the draft of the 2025 Korean H. pylori guidelines. We examined the rationale for abandoning TT as a first-line empirical therapy and the establishment of a new dual-pillar strategy: 1) the declining role of clarithromycin-containing TT as a first-line treatment and 2) polymerase chain reaction (PCR)-based tailored therapy as the recommended precision approach. We explored the 1) emergence of new empirical regimen options, 2) application of tailored therapy, and 3) adoption of potassium-competitive acid blockers (P-CABs). Empirical regimens have shifted toward four-drug combinations to achieve higher cure rates. Concomitant therapy (proton-pump inhibitor [PPI] or P-CAB+amoxicillin+clarithromycin+metronidazole) offers high efficacy but raises concerns about antibiotic overuse. As a compromise, bismuth-augmented triple regimens (adding bismuth to TT) are now recommended; these modified quadruple therapies (e.g., PACB: PPI+amoxicillin+clarithromycin+bismuth, or PAMB: PPI+amoxicillin+metronidazole+bismuth) significantly improve eradication rates without requiring a third antibiotic class. Regarding tailored therapy, PCR-based domestic clinical research data consistently achieves ≥90% cure rates in first-line treatment—markedly higher than empirical TT in Korea. Economic analyses supported the cost-effectiveness of this approach. The guideline algorithm for salvage therapy was clarified. Bismuth quadruple therapy has been confirmed as the standard second-line treatment. For third-line therapy, we analyzed the efficacy of levofloxacin-based regimens, rifabutin-based therapy, and bismuth add-on therapy with two previously unused antibiotics. The 2025 Korean guidelines establish quadruple therapies as the new standard through a dual strategy: pragmatic empirical treatment and PCR-guided tailored therapy, with P-CABs and bismuth-based regimens as key components.

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.

Purpose: Axillary surgery is increasingly omitted in patients with early-stage breast cancer undergoing upfront surgery, as supported by trials such as SOUND and INSEMA. However, in the neoadjuvant setting, the omission of axillary surgery has only been explored in small single-arm studies involving highly selected patients with confirmed breast pathologic complete response (pCR). The NeoNAUTILUS trial aimed to evaluate the oncologic safety of omitting sentinel lymph node biopsy (SLNB) in patients with a high probability of achieving an axillary pCR (ypN0) following neoadjuvant systemic therapy (NST), regardless of breast pCR status. Methods NeoNAUTILUS is a prospective, multicenter, randomized, controlled, noninferiority trial conducted at 12 tertiary centers in Korea. Eligible participants were women with clinical T1–T3, N0, or selected N1 invasive breast cancer, who completed NST and were candidates for breast-conserving surgery (BCS). Prior to enrollment, all patients underwent axillary ultrasound after NST completion to exclude suspicious lymph nodes. Patients with clinical N0 disease of any subtype were eligible for inclusion. Patients with clinical N1 disease with human epidermal growth factor receptor 2-positive or triple-negative tumors may be included if their primary tumor demonstrates a > 30% reduction on magnetic resonance imaging after NST. Participants were randomized 1:1 to undergo BCS with or without SLNB, stratified by clinical nodal status and tumor subtype. Patients were randomized and remained blinded until surgery. The primary endpoint is the 5-year invasive disease-free survival. A total of 464 patients are expected to be enrolled over 3 years, with a 5-year follow-up period.Discussion: NeoNAUTILUS is the first randomized trial to assess the omission of axillary surgery after NST based on the predicted nodal response, independent of breast pCR. This study may redefine axillary management in the neoadjuvant setting by identifying patients who can safely avoid SLNB, thereby reducing surgical morbidity without compromising oncologic outcomes.

This case report presents the successful endoscopic submucosal dissection (ESD) of a well-differentiated esophageal liposarcoma in a 51-year-old male with persistent dysphagia. The cause was initially diagnosed as a 10 cm pedunculated lesion extending from the upper esophageal sphincter to the mid-esophagus. An ESD was chosen over traditional surgery because it is less invasive. The procedure involved a precise submucosal injection and excision with special techniques to manage bleeding from a central vessel.Despite the extraction challenges owing to the size of the lesion, it was successfully removed orally. A histopathological examination of the 8.3×4.2×2.3 cm specimen revealed the characteristic features of a well-differentiated liposarcoma, including MDM2 and CDK4 positivity. The follow-up revealed no recurrence, and active surveillance has been performed since. This report highlights the versatility of ESD in treating significant esophageal tumors and provides evidence for its efficacy as a minimally invasive alternative.

Gastritis is a disease characterized by inflammation of the gastric mucosa. It is very common and has various classification systems such as the updated Sydney system. As there is a lot of evidence that Helicobacter pylori infection is associated with the development of gastric cancer and that gastric cancer can be prevented by eradication, H. pylori gastritis has been emphasized recently. The incidence rate of gastric cancer in Korea is the highest in the world, and due to the spread of screening endoscopy, atrophic gastritis and intestinal metaplasia are commonly diagnosed in the general population. However, there have been no clinical guidelines developed in Korea for these lesions. Therefore, this clinical guideline has been developed by the Korean College of Helicobacter and Upper Gastrointestinal Research for important topics that are frequently encountered in clinical situations related to gastritis. Evidence-based guidelines were developed through systematic review and de novo processes, and eight recommendations were made for eight key questions. This guideline needs to be periodically revised according to the needs of clinical practice or as important evidence about this issue is published in the future.

Esophageal perforation can lead to serious complications, and rapid diagnosis and treatment significantly affect the prognosis. Endoscopic vacuum-assisted closure (EndoVAC) therapy is widely accepted as a safe, well-tolerated, effective, versatile and practical procedure for the management of esophageal perforation in selected patients. We report the successful use of EndoVAC therapy for management of an esophageal perforation secondary to foreign body removal. A 56-year-old man presented to the emergency department for evaluation of chest pain after swallowing the plastic shell of a pill. Emergency endoscopy revealed an esophageal wall laceration (approximately 3 cm) and microperforation. The esophageal laceration and microperforation were limited to the mid-esophagus. The patient underwent EndoVAC therapy, which was repeated every 3–4 days for a total of six sessions over a period of 21 days. We observed improvement in the esophageal injury with granulation tissue formation during the fifth session. Subsequent follow-up evaluation, including esophagography and chest computed tomography confirmed complete healing of the esophageal injury. Following resumption of diet, the patienton a was discharged without any complications.

Background/Aims: We aimed to evaluate the histologic features predictive of prognosis and correlate them with endoscopic findings in patients with ulcerative colitis (UC) having complete or partial mucosal healing (MH). Methods: We prospectively collected and reviewed data from patients with UC who underwent colonoscopy or sigmoidoscopy with biopsy. Complete and partial MH were defined as Mayo endoscopic subscores (MESs) of 0 and 1, respectively. Histologic variables, including the Nancy index (NI), predicting disease progression (defined as the need for medication upgrade or hospitalization/surgery), were evaluated and correlated with endoscopic findings. Results: Overall, 441 biopsy specimens were collected from 194 patients. The average follow-up duration was 14.7 ± 7.4 months. There were 49 (25.3%) and 68 (35.1%) patients with MESs of 0 and 1, respectively. Disease progression occurred only in patients with an MES of 1. NI ≥ 3 was significantly correlated with disease progression during follow-up. Mucosal friability on endoscopy was significantly correlated with NI ≥ 3 (61.1% in NI < 3 vs. 88.0% in NI ≥ 3; p = 0.013). Conclusions Histological activity can help predict the prognosis of patients with UC with mild endoscopic activity. Mucosal friability observed on endoscopy may reflect a more severe histological status, which can be a risk factor for disease progression.