Purpose: The selection of primary tumor resection (PTR) vs. self-expanding metallic stents (SEMS) in obstructive unresectable stage IV colorectal cancer (CRC) is critical, profoundly impacting patient outcome. This study evaluates the influence of PTR and SEMS on overall survival (OS) in conjunction with chemotherapy. Methods: The analysis included 137 patients with obstructive, unresectable stage IV CRC who underwent PTR or attempted SEMS placement. The primary objective was to assess the OS of patients, specifically examining how PTR and SEMS interventions influence these survival outcomes. Results: In a cohort of 137 patients with obstructive, unresectable stage IV CRC, 30 initially opted for PTR, while stent placement was attempted in 107 cases. Following 14 stent failures, which resulted in 8 diversions and 6 additional PTR interventions, exclusions due to elective surgeries led to a final analysis of 36 PTR and 72 SEMS cases. Cox regression analysis identified no significant survival advantage between PTR and SEMS interventions (hazard ratio [HR], 0.848; 95% confidence interval [CI], 0.555–1.298; P = 0.449). Critical findings highlighted that the absence of chemotherapy markedly reduced survival prospects (HR, 1.963; 95% CI, 1.200–3.211; P = 0.007). These insights were substantiated through propensity score matching. Conclusions The comparative analysis reveals that neither PTR nor SEMS offers a definitive survival advantage in managing obstructive, unresectable stage IV CRC. However, the necessity for subsequent invasive interventions is notably lower in the PTR group.

Multiple myeloma (MM), a hematological malignancy, is characterized by malignant plasma cell proliferation in the bone marrow. Recent treatment advances have significantly improved patient outcomes associated with MM.In this study, we aimed to develop comprehensive, evidence-based guidelines for the diagnosis, prognosis, and treat‑ ment of MM. We identified 12 key clinical questions essential for MM management, guiding the extensive literature review and meta-analysis of the study. Our guidelines provide evidence-based recommendations by integrating patient preferences with survey data. These recommendations include current and emerging diagnostic tools, thera‑ peutic agents, and treatment strategies. By prioritizing a patient-centered approach and rigorous data analysis, these guidelines were developed to enhance MM management, both in Korea and globally.

Ancient schwannoma is a variant of schwannoma characterized by slow progression, degenerative changes, and a higher incidence in older adults. There have been two prior reported cases of ancient schwannoma arising from the distal ulnar nerve at the wrist level, but neither were longstanding or very large. Herein, we report an ancient schwannoma found in the ulnar nerve of the distal forearm that was found to be clinically meaningful in size. A 61-year-old man presented with complaints of tingling sensation of the fourth and fifth fingers and bulging of the ulnar side of the wrist. The patient reported that the mass in his wrist had grown very slowly, starting about 10 years ago, and that he had started experiencing a tingling sensation in his fourth and fifth fingers about 3 years prior, which had become worse in the past year. Based on the results of the preoperative examination, a benign nerve sheath tumor was suspected. As it was thought that the possibility of malignancy was not high, we elected to perform a marginal excision. Pathological examination confirmed ancient schwannoma. At his most recent visit, 3 years after surgery, he reported no recurrence and that he felt better than before surgery, but some tingling sensations remained. As with small ancient schwannoma in the distal wrist, most cases of large ancient schwannoma can be treated without special complications based on an accurate preoperative diagnosis.

Purpose: Programmed death-1 blockade with pembrolizumab has shown promising activity in relapsed/refractory (R/R) extranodal natural killer/T-cell lymphoma (NKTCL), but studies are limited, with small patient numbers. Materials and Methods: Thirteen institutes involved with the Consortium for Improving Survival of Lymphoma, a Korean lymphoma study group, collected the clinical data of 59 patients treated with pembrolizumab as salvage therapy between 2016 and 2022. Results: The median age of the patients was 60 years (range, 22 to 87 years), and 76.3% had advanced Ann Abor stage disease. Pembrolizumab was given to 35.6%, 40.7%, and 23.7% of the patients as second-, third-, and fourth- or higher-line chemotherapy, respectively. The overall response rate was 40.7%, with 28.8% having complete response. The estimated 2-year progression-free survival (PFS) and overall survival rates for all patients were 21.5% and 28.7%, respectively; for responders, the rates were 53.0% and 60.7%, respectively. Although not statistically significant, Eastern Cooperative Oncology Group performance status ≥ 2 (hazard ratio [HR], 1.91; 95% confidence interval [95% CI], 0.93 to 3.94; p=0.078) and stage III or IV disease (HR, 2.59; 95% CI, 0.96 to 6.96; p=0.060) were associated with a trend toward shorter PFS in multivariate analysis. Grade 3 or 4 adverse events (AEs) were noted in 12 patients (20.3%); neutropenia (10.2%), fatigue (6.8%), and pneumonitis (5.1%) were most common AEs. Conclusion In conclusion, while pembrolizumab had a modest effect on patients with R/R NKTCL, it may be a useful salvage therapy for patients with localized disease and good performance status.

There are limited data on outcomes after implantation of everolimus-eluting stents (EES) in East Asian patients with small vessel coronary lesions. A total of 1,600 patients treated with XIENCE EES (Abbott Vascular, CA, USA) were divided into the small vessel group treated with one ≤2.5 mm stent (n=119) and the non-small vessel group treated with one ≥2.75 mm stent (n=933). The primary end point was a patient-oriented composite outcome (POCO), a composite of all-cause death, myocardial infarction (MI), and any repeat revascularization at 12 months. The key secondary end point was a device-oriented composite outcome (DOCO), a composite of cardiovascular death, target-vessel MI, and target lesion revascularization at 12 months. The small vessel group was more often female, hypertensive, less likely to present with ST-elevation MI, and more often treated for the left circumflex artery, whereas the non-small vessel group more often had type B2/C lesions, underwent intravascular ultrasound, and received unfractionated heparin. In the propensity matched cohort, the mean stent diameter was 2.5±0.0 mm and 3.1±0.4 mm in the small and non-small vessel groups, respectively. Propensity-adjusted POCO at 12 months was 6.0% in the small vessel group and 4.3% in the non-small vessel group (p=0.558). There was no significant difference in DOCO at 12 months (small vessel group: 4.3% and non-small vessel group: 1.7%, p=0.270).Outcomes of XIENCE EES for small vessel disease were comparable to those for non-small vessel disease at 12-month clinical follow-up in real-world Korean patients.

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.

The global resurgence of bed bug infestations, exacerbated by increasing international travel, trade, and insecticide resistance, has significantly impacted Korea. This study identified the bed bug species and performed pyrethroid resistance genotyping of recently resurgent bed bugs in Korea. Thirty-one regional bed bug samples were collected from 5 administrative regions: Gyeonggi-do (n=14), Seoul (n=13), Busan (n=2), Jeonllanam-do (n=1), and Chungcheongbuk-do (n=1). The samples underwent morphological and molecular identification. Twenty-four regional samples (77.4%) were identified as the tropical bed bug, Cimex hemipterus, and the remaining 7 regional samples (22.6%) were identified as the common bed bug, Cimex lectularius. The C. hemipterus regional samples carried at least three mutations associated with knockdown resistance (kdr), including 2 super-kdr mutations. The 7 C. lectularius regional samples possessed at least one of the 3 kdr-related mutations associated with pyrethroid resistance. This study confirms that the prevalent bed bug species recently in Korea is C. hemipterus, replacing the previously endemic C. lectularius. Additionally, the rise in bed bug populations with pyrethroid resistance underscores the necessity of introducing alternative insecticides.