Purpose: Human epidermal growth factor receptor 2 (HER2) is amplified or overexpressed in various malignancies, including breast and gastric cancers, and is associated with poor prognosis. Although HER2-targeted therapies, such as trastuzumab, improve outcomes in HER2-positive tumors, resistance often develops, and HER2-low tumors remain largely untargeted. Trastuzumab deruxtecan (T-DXd; DS-8201a) is a HER2-targeted antibody-drug conjugate with potent activity in HER2-positive and HER2-low tumors. This study evaluates its antitumor mechanisms and efficacy in HER2-positive, HER2-low, and homologous recombination deficiency (HRD)–associated models. Materials and Methods: Effects of T-DXd were assessed in cancer cell lines with diverse HER2 expression and HRD status. In vivo efficacy was evaluated using a xenograft model derived from HER2-low SNU-601 gastric cancer cells. Results: T-DXd reduced HER2 phosphorylation and downstream signaling (AKT, ERK) in HER2-positive cells. It induced DNA damage accumulation, as evidenced by increased γH2AX and p-Chk1 expression, and triggered apoptosis through cleaved poly(ADP-ribose) polymerase and caspase-3 activation, confirmed by annexin V staining. Similar effects were observed in HER2-low cells, with greater sensitivity in HRD cells. In xenografts, T-DXd reduced tumor volume by up to 80% at 4 mg/kg and 10 mg/kg. Histological analyses showed decreased Ki-67 and increased apoptosis. Furthermore, T-DXd induced G2/M cell cycle arrest and nuclear anaplasia, suggesting disruption of chromosomal stability as a potential antitumor mechanism. No significant toxicity, including body weight loss, was observed. Conclusion These findings highlight T-DXd’s effectiveness in HER2-low and HRD tumors, supporting its broader clinical application, including strategies targeting DNA damage repair pathways.

Purpose: Malignant hepatocellular neoplasm, not otherwise specified (HCN-NOS) is a provisional diagnostic entity, characterised by intermediate or a combination of hepatoblastoma and pediatric hepatocellular carcinoma (p-HCC) features. We compared the characteristics of HCN-NOS with hepatoblastoma and p-HCC. Materials and Methods: The records of 148 pediatric patients diagnosed with hepatocellular malignancy after resection were retrieved from the institutional database. Clinical parameters and histopathology slides were reviewed to re-establish each patient’s diagnosis. Molecular analyses were conducted in 37 patients. Results: Patients were profiled as 21 (14.2%) with HCN-NOS, 109 (73.6%) with hepatoblastoma, and 18 (12.2%) with p-HCC. The median age was 8.6 years in HCN-NOS, 1.2 years in hepatoblastoma, and 7.9 years in p-HCC. Background liver disease was frequently observed in p-HCC (11/18, 61%) but infrequent in HCN-NOS (4/21, 19%) and hepatoblastoma (4/109, 3.7%). HCN-NOS presented with a more advanced PRETEXT stage (p=0.012), metastasis (p < 0.001), and lymphovascular invasion (p < 0.001) than hepatoblastoma and p-HCC. Patients with HCN-NOS received longer cycles of preoperative chemotherapy; however, they reported a lower decrease in serum alpha-fetoprotein and tumor size than hepatoblastoma (p=0.043, p=0.004, and p=0.044, respectively). HCN-NOS was an independent poor prognostic factor for event-free survival (hazard ratio, 4.968; 95% confidence interval, 2.004 to 12.32; p < 0.001). Conclusion The possibility of HCN-NOS should be considered in pediatric patients with liver cancer, especially those ≥ 5 years old with no background liver disease. Because HCN-NOS exhibits poor chemoresponsiveness and unfavourable postoperative prognosis, liver transplantation should be strongly considered.

Background/Aims: Although mucosal healing (MH) is acknowledged as the treatment target in the treat-to-target era, there are limitations on repeated endoscopic examinations, especially in pediatric patients. We aimed to investigate whether fecal calprotectin (FC) could serve as a surrogate marker for the assessment of MH in pediatric patients with Crohn’s disease (CD) who have achieved sustained clinical remission (CR) while treated with anti-tumor necrosis factor (TNF) agents. Methods: This multicenter retrospective cross-sectional study included pediatric CD patients who had sustained a CR for at least 6 months with anti-TNF agents and who simultaneously underwent ileocolonoscopy and FC tests during follow-up. MH was defined as the absence of any ulcer on ileocolonoscopy. Results: A total of 131 patients were included in this study. MH was observed in 87 patients (66.7%). The FC level was significantly lower in patients with MH than in those without MH (median 49.0 mg/kg vs 599.0 mg/kg; p<0.001). According to the multivariate logistic regression analysis, FC was the only factor associated with MH (odds ratio, 0.62; 95% confidence interval [CI], 0.52 to 0.73; p<0.001). According to the receiver operating characteristic curve analysis, the optimal cutoff value for FC for the association with MH was <140 mg/kg (area under the curve 0.890, 95% CI 0.829 to 0.951, sensitivity 78.2%, specificity 88.6%, p<0.001). Conclusions FC was associated with MH in pediatric patients with CD who had achieved a sustained CR for at least 6 months with anti-TNF agents. In these patients, FC can be used to stratify patients and guide decisions regarding ileocolonoscopy in the treat-to-target era.

Purpose: The objective of this study was to identify the significance of 24-hour postreduction ultrasonography (US) in pediatric patients with intussusception. Methods: A total of 229 patients with intussusception who were treated with saline reduction at Severance Children’s Hospital between January 2014 and September 2020 were retrospectively reviewed. The 229 patients with successful saline reduction were divided into two groups: a recurrence at 24 hours group (R, n=41) and a non-recurrence group (NR, n=188). The full patient sample was divided into two groups: follow-up US (FU) or no followup US (NFU); the recurrence group was divided into follow-up (R-FU) and non-follow-up (R-NFU) subgroups, and stratified analyses were performed. Results: There were no significant differences in age, sex, laboratory findings, symptoms, and sonographic findings between the NR and R groups. In the R group, 24 patients underwent follow-up US, and 17 patients did not. Specific sonographic findings were statistically significant in the R-FU group compared to the R-NFU group (p=0.002). The R-FU group had fewer admissions (p=0.012) and longer mean hospitalization times (p<0.001) than the R-NFU group. The NFU group had a 12.2% recurrence rate, while the R-FU group recurrence rate was 25.8% (p=0.0099), suggesting that the omission of some recurrent events and follow-up US was a significant variable in the recurrence of intussusception. The median time to recurrence was 21 hours which supports the 24-hour follow-up protocol. Conclusion Twenty-four-hour follow-up US was shown to be valuable for detecting early recurrence of intussusception.

Background/Aims: We aimed to compare the differences in pediatric Crohn’s disease (CD) and ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted at five centers in Korea between 2013 and 2017. Baseline demographics, clinical characteristics, and results from laboratory, endoscopic, radiologic examinations were compared between pediatric CD and UC patients who were <19 years old at diagnosis. Results: A total 307 patients were included (227 CD [73.9%] and 80 UC [26.1%]). The male to female ratio was 2.49:1 for CD, and 1.49:1 for UC (p=0.019). Median age at diagnosis was 14.4 years (interquartile range, 12.4 to 16.2) for CD, and 14.4 years (interquartile range, 11.7 to 16.5) for UC (p=0.962). Hematochezia was the only dominant symptom in UC patients compared to CD patients (86.2% vs 30.8%, p<0.001). White blood cell counts, platelet counts, erythrocyte sedimentation rate, and C-reactive protein levels were significantly higher, and serum albumin level was significantly lower in CD patients than in UC patient. Anti-Saccharomyces cerevisiae antibody was positive in 44.5% and 16.2% of CD and UC patients, respectively (p<0.001), and antineutrophil cytoplasmic antibody was positive in 15.0% and 58.8% of CD and UC patients, respectively (p<0.001). Terminal ileal involvement was prominent in CD, while rectal involvement was more prominent in UC. Small bowel involvement and perianal perforating diseases were also more prominent in CD. Conclusions This is the first a multicenter study in Korea to compare the differences between pediatric CD and UC at diagnosis in Korea. A large-scale, national study is expected to better clarify these findings in the future.

Background: Dual energy X-ray absorptiometry (DXA) has evolved from pencil-beam (PB) to narrow fan-beam (FB) densitometers. We performed a meta-analysis of the available observational studies to determine how different modes of DXA affect bone mineral density (BMD) measurements. Methods: A total of 1,233 patients (808 women) from 14 cohort studies were included. We evaluated the differences in BMD according to the DXA mode: PB and FB. Additionally, we evaluated the differences in BMD between the 2 types of FB mode: FB (Prodigy) and the most recent FB (iDXA). Pairwise meta-analysis was performed, and weighted mean differences (WMD) were calculated for (total lumbar, total hip, and total body). Results: No significant difference was observed in total lumbar (pooled WMD, -0.013; P=0.152) and total hip BMD (pooled WMD, -0.01; P=0.889), between PB and FB. However, total body BMD was significantly lower in the PB compared to the FB group (pooled WMD, -0.014; P=0.024). No significant difference was observed in lumbar BMD (pooled WMD, -0.006; P=0.567), total hip (pooled WMD, -0.002; P=0.821), and total body (pooled WMD, 0.015; P=0.109), between Prodigy and iDXA. Conclusions The results of this study warrant the recommendation that correction equations should not be used when comparing BMD from different modes. Further research is still needed to highlight the ways in which differences between DXA systems can be minimized.

In Korea, the Hospice, Palliative Care, and Life-sustaining Treatment Decision-making Act was enacted in February 2016 in order to ensure that the patient's self-determination in end-of-life care processes is respected. To enhance physicians' understanding of this act and to provide proper criteria for medical judgment in variety of clinical settings, consensus guidelines were published in November 2016. In this article, the characteristics of these guidelines and related issues regarding the definitions of ‘the end stage of disease’ and ‘last days of life’ and the criteria for medical judgment are presented and summarized. According to the guidelines, the term ‘end stage of disease’ refers to a state in which there is no possibility of a fundamental recovery and the symptoms are expected to worsen within months. The terms ‘the last days of life’ and ‘the final days of life’ refer to a state in which, despite treatment, the patient's condition is worsening and death is impending, with no possibility of recovery. The attending physician and another relevant specialist should both judge a patient's medical condition as either ‘end stage of disease’ for hospice/palliative care or ‘the last days of life’ for dying patient care according to the law. Caregivers should provide appropriate medical information to eligible patients for palliative or ‘end stage of disease’ care through advance care planning. Therefore, it is critically necessary that caregivers understand the legitimate process of hospice/palliative and dying patient care based on the patient's wishes and best interests. Physicians should apply these consensus guidelines to eligible patients considering their clinical course and the patients' wishes.
Advance Care Planning ; Caregivers ; Consensus ; Hospices ; Humans ; Judgment ; Jurisprudence ; Korea ; Palliative Care ; Patient Care ; Specialization

In Korea, the Hospice, Palliative Care, and Life-sustaining Treatment Decision-making Act was enacted in February 2016 in order to ensure that the patient's self-determination in end-of-life care processes is respected. To enhance physicians' understanding of this act and to provide proper criteria for medical judgment in variety of clinical settings, consensus guidelines were published in November 2016. In this article, the characteristics of these guidelines and related issues regarding the definitions of ‘the end stage of disease’ and ‘last days of life’ and the criteria for medical judgment are presented and summarized. According to the guidelines, the term ‘end stage of disease’ refers to a state in which there is no possibility of a fundamental recovery and the symptoms are expected to worsen within months. The terms ‘the last days of life’ and ‘the final days of life’ refer to a state in which, despite treatment, the patient's condition is worsening and death is impending, with no possibility of recovery. The attending physician and another relevant specialist should both judge a patient's medical condition as either ‘end stage of disease’ for hospice/palliative care or ‘the last days of life’ for dying patient care according to the law. Caregivers should provide appropriate medical information to eligible patients for palliative or ‘end stage of disease’ care through advance care planning. Therefore, it is critically necessary that caregivers understand the legitimate process of hospice/palliative and dying patient care based on the patient's wishes and best interests. Physicians should apply these consensus guidelines to eligible patients considering their clinical course and the patients' wishes.