Background: In the era of nucleoside analogs (NA), we investigated the safety of using hepatitis B surface antigen (HBsAg)-positive grafts in liver transplantation (LT) using nationwide KOTRY data. Methods: Among 4,265 adult LTs in the KOTRY registry (April 2014–January 2020), 20 (0.5%) used HBsAg(+) grafts. The S(+) group was compared with HBsAg-nega-tive groups, both HBcAb(+) (C[+]) and HBcAb(−) (SC[−]), using 1:1 propensity scorematching. Patient and graft survival were evaluated using Kaplan–Meier analysis.Cox regression was used to identify prognostic factors. Results: No significant differences were observed in patient or graft survival be-tween S(+) and C(+) or SC(−) groups. Key prognostic factors for patient survivalincluded age, HCC, MELD score, ascites, and encephalopathy. For graft survival, HCC, preoperative HCC treatment, MELD score, ascites, and encephalopathy were significant. HBV recurrence occurred in the S(+) group, but did not compromise outcomes. Conclusion In HBV-endemic regions, HBsAg(+) liver grafts can be safely used to expand the donor pool without compromising LT outcomes when combined with appropriate prophylaxis.

Purpose: While MRI-based tumor regression grade (mrTRG) has shown promise in evaluating pathologic response to concurrent chemoradiotherapy (CCRT) in rectal cancer, its ability to predict pathologic complete response remains limited.This study aimed to enhance mrTRG’s diagnostic performance in predicting ypT0–1N0 status, a key factor in considering non-radical management after CCRT for locally advanced rectal cancer (LARC). Methods: This retrospective study included 430 patients with LARC who underwent radical resection following CCRT at a single referral hospital between April 2018 and September 2024. Multivariable logistic regression was used to identify predictive factors associated with achieving ypT0–1N0 status. The diagnostic performances of mrTRG1–2 alone and in combination with other factors were assessed by comparing sensitivity, specificity, positive-predictive value (PPV), negative-predictive value, and area under the curve (AUC). Results: Ninety-three patients (21.6%) achieved ypT0–1N0. In the multivariable analysis, fungating type, cT1–2, and mrTRG1–2 were independent predictors for ypT0–1N0. Integrating mrTRG with gross tumor type yielded the highest AUC of 0.689 among the combined models. For predicting ypT0–1N0, the combination of mrTRG and gross tumor type improved PPV (79.2% vs. 41.5% for mrTRG alone) while also demonstrating enhanced sensitivity compared with ycT0–1N0, the conventional MRI-based predictor (40.9% vs. 22.6%). Conclusion This study demonstrated that combining mrTRG and gross tumor type improved the PPV of mrTRG in predicting ypT0–1N0 after CCRT in LARC. Further studies are warranted to validate the role of gross tumor type in refining predictive systems for selecting candidates for non-radical treatment.

Purpose: Weight reduction (WR) can reduce liver volume, affecting the graft-to-recipient weight ratio (GRWR). This study aimed to evaluate the decrease in liver volume after WR and analyze risk factors affecting liver volume reduction in potential liver donors with steatosis. Methods: We retrospectively reviewed data of 147 potential liver donors with steatosis who participated in a WR program prior to liver transplantation between January 2016 and December 2021. Total liver volume (TLV) was measured using CT and MRI. Risk factors for large liver volume reduction (≥10%) were analyzed using multivariate logistic regression. Results: Ninety-seven donors (66.0%) underwent donor hepatectomy after WR. Liver volumes showed a statistically significant decrease (from 1,399.6 ± 315.4 mL to 1,283.6 ± 271.2 mL, P < 0.05). Thirty-eight donors (42.7%) showed large liver volume reduction. There was a more significant reduction in weight, AST, and ALT in the large liver volume reduction group than in the small liver volume reduction group (all P < 0.05). WR percentage and ALT abnormalities were independent risk factors for large liver volume reduction (odds ratio, 1.184 [95% confidence interval, 1.054–1.329] and odds ratio, 5.502 [95% confidence interval, 1.660–18.229], respectively; all P < 0.05). Conclusion Potential liver donors with 7% or more WR or ALT abnormality require liver volume/GRWR remeasurement after WR to ensure adequate graft size and prevent small-for-size syndrome.

Purpose: This study aimed to evaluate surgical outcomes, identify complications, and analyze recurrence in patients undergoing surgery for primary retroperitoneal tumors (RPTs), which pose significant therapeutic challenges. Methods: We retrospectively reviewed the medical records of 59 patients who underwent surgery for primary RPTs at Ajou University Hospital between January 2015 and December 2024. Patients were divided into a multivisceral resection (MVR) group (n = 25) and a non-MVR group (n = 34) to compare demographics, clinical characteristics, pathological findings, and postoperative outcomes. Results: Compared to the non-MVR group, the MVR group had a significantly higher rate of open surgery (96.0% vs.73.5%, P = 0.034), longer operative times (237.6 minutes vs. 188.8 minutes, P = 0.032), more frequent R2 resections (32.0% vs. 8.8%, P = 0.018), and longer hospital stays (13.1 days vs. 7.0 days, P = 0.007). Malignant tumors comprised 67.7% of cases, with sarcoma being the most common. Recurrence rates were highest in well-differentiated liposarcoma (50.0%) and dedifferentiated liposarcoma (22.2%). While univariate analysis showed MVR was associated with severe morbidity (Clavien-Dindo grade ≥III; odds ratio, 6.200; P = 0.029), this was not sustained as an independent predictor in multivariable analysis. Conclusion Although MVR was associated with severe complications in univariate analysis, it was not an independent predictor in multivariable analysis. This suggests the increased risk reflects overall surgical complexity. Therefore, MVR should be pursued when oncologically necessary, as it presents an acceptable morbidity profile.

Purpose: Neoadjuvant treatment (NAT) is now the standard for borderline resectable pancreatic cancer (RPC) and is being considered for RPC. Early recurrence after curative surgery in RPC is often seen as a treatment failure, prompting considerations for NAT. Our goal was to develop an artificial intelligence (AI)-based predictive model utilizing preoperatively available factors to forecast early recurrences of resected RPC. Methods: This study included 469 patients who underwent surgery for RPC between 2011 and 2019. Clinicopathologic and oncologic data were retrospectively reviewed. Preoperative variables, including laboratory data and imaging findings, were collected. Early recurrence was defined as recurrence occurring within a year after surgery. Deep neural networks were then used to select variables by assessing their importance. A new model predicting early recurrence of RPC was subsequently developed. Results: Of the patients evaluated, 199 (42.4%) experienced early recurrence. The predictive model included 14 preoperative variables: CA 19-9, preoperative pancreatitis, serum albumin, platelet count, lymphocyte count, the American Society of Anesthesiologists physical status classification, tumor size, monocyte count, age, body mass index, CRP, hemoglobin, WBC count, and CEA. The area under the curve for the model was 0.786 in the training set and 0.734 in the test set. Conclusion We developed an AI-based model to predict the early recurrence of RPC using preoperative parameters. By identifying patients at risk of early recurrence, optimal individualized treatments such as NAT can be considered. Future prospective studies are crucial to establish clear indications for NAT in RPC.

Robotic thyroidectomy has progressed from multiport to single-port (SP) platforms to minimize invasiveness and improve cosmesis. The da Vinci SP system (Intuitive Surgical) combines a flexible 3-dimensional endoscope with 3 wristed instruments in a single 2.5-cm cannula-enabled concealed remote access route and mitigates external arm collisions.This review synthesized PubMed-indexed reports (2020–2025) on SP robotic thyroidectomy using the following approaches:transaxillary variants, SP areolar, retroauricular/facelift (SP-hairline variants), and transoral approach. We focused on technical refinement, learning curves, and clinical outcomes. We highlight technical refinements and clinical outcomes across access routes. Contemporary series indicate that SP thyroidectomy is feasible and safe in well-selected patients, with high cosmetic satisfaction and operative metrics comparable to those of multiport cohorts. Among the SP routes, transaxillary variants have the most mature peer-reviewed reporting and are therefore discussed in greater detail. Early applications of SP-assisted lateral neck dissection have also been described. The limitations of current SP platforms include constrained counter-traction, reduced internal workspace, and incomplete integration of advanced energy devices.Nonetheless, ongoing device innovations and the growing global experience suggest that SP systems will increasingly shape endocrine neck surgeries.

Purpose: Pediatric surgery in Korea has historically been undervalued under the national fee system. Since 2021, the government has progressively expanded surgical add-on reimbursement for pediatric surgeries, yet their real-world impact remains unclear. Methods: We retrospectively analyzed pediatric surgeries (<19 years) performed at 4 tertiary institutions from 2020 to 2025. Surgeries were divided into 4 periods based on major policy changes. Variables included the number of surgeries, claimed surgical fees, patient age and weight, and eligibility for add-on reimbursement. Trends over time and variations among hospitals were examined. Results: A total of 1,959 surgeries were analyzed. Surgical volume did not significantly change across periods (P = 0.342).In contrast, total claimed surgical fees increased 1.66-fold in Period 2, 3.26-fold in Period 3, and 3.42-fold in Period 4 compared with Period 1. The proportion of surgeries eligible for add-on reimbursement rose to 76.6% in Period 4. The average claimed fee per case increased from 973,446 Korean won in Period 1 to 3,463,428 in Period 4. Patients <1,500g demonstrated the largest increase (471%). Across hospitals, the magnitude of claimed fee increases varied, but all institutions showed substantial growth in claimed surgical fees. Conclusion Stepwise expansion of pediatric surgical add-on reimbursement substantially increased claimed surgical fees across institutions without inflating surgical volume. These reforms improved financial reimbursement and may support future improvements in workforce sustainability, training, and care equity. Continuous policy monitoring will be essential to ensure long-term effectiveness and fiscal balance.

Purpose: Postoperative complications following gastric cancer surgery significantly impact patient outcomes, yet standardized definitions for these events have not been consistently applied across institutions in Korea. This study aimed to develop a consensus-based, standardized complication classification system specific to gastrectomy for gastric cancer as part of the Korean Quality Improvement Platform in Surgery (K-QIPS) initiative. Methods: As part of K-QIPS, a dedicated task force team (TFT) was formed with surgical experts from fourteen high-volume hospitals across Korea. The TFT conducted ten formal meetings to review existing literature and international guidelines, and incorporated findings from randomized controlled trials. The final complication list was developed through expert consensus and structured into a standardized framework. A Data Entry Manual was created to support consistent data collection by surgical clinical reviewers. Results: The TFT defined specific postoperative complications following gastrectomy for gastric cancer, including anastomotic leakage, duodenal stump leakage, pancreatic fistula, intra-abdominal and luminal bleeding, delayed gastric emptying, and internal hernia. Notably, internal hernia was described in standardized form for the first time. General complications were developed first and overlapped in part with the gastric cancer-specific list. The task force also produced a Data Entry Manual that provides practical instructions to ensure consistency and accuracy in complication reporting. Conclusion This nationwide consensus initiative established the first standardized complication classification system for gastric cancer surgery in Korea. The proposed definitions and data entry system are expected to improve complication reporting, enable multicenter research, support surgical quality benchmarking, and ultimately enhance patient outcomes.

Purpose: Drainage fluid may serve as a biologically informative indicator of immune and infectious status during postsurgical recovery after trauma. However, microbiome shifts in drainage fluid associated with clinical resilience have not yet been characterized. This study aimed to investigate microbial dynamics in drainage fluid across the intensive care unit (ICU) and ward recovery phases in Korean trauma patients. Methods: A total of 25 drainage and 10 stool samples were collected from 10 trauma patients who underwent abdominal surgery at a regional trauma center. Microbial composition was analyzed using 16S ribosomal RNA amplicon sequencing.Alpha and beta diversity were compared between sample types and recovery stages. Linear mixed-effects models were used to identify recovery-associated taxa while adjusting for clinical variables, and predicted metabolic pathways were assessed using PICRUSt2. Results: Drainage fluid harbored distinct microbial communities independent of the intestinal microbiota. Shared taxa between drainage and stool increased significantly in patients with bowel injury, suggesting microbial translocation.Seven genera and 5 species showed significantly decreased abundance during the ward stage, with Modestobacter and Blastococcus tunisiensis demonstrating the highest discriminative ability between recovery stages (area under the curve = 0.721). Predicted metabolic pathways related to fatty acid degradation, amino acid degradation, and pro-inflammatory processes were more active during the ICU stage. Conclusion These findings provide preliminary evidence that drainage fluid microbiome profiles may reflect recovery dynamics following trauma, supporting its potential utility for microbiome-based monitoring and biomarker discovery in trauma surgery.

Purpose: Colorectal cancer (CRC) remains a leading cause of cancer-related mortality, necessitating the identification of novel therapeutic targets. The E3 ubiquitin ligase WW domain-containing E3 ubiquitin protein ligase 2 (WWP2) has been implicated in various cancers, yet its specific role and underlying molecular mechanisms in CRC are poorly understood. This study aimed to investigate the functional role of WWP2 in CRC progression and to elucidate its regulatory mechanisms. Methods: WWP2 expression was evaluated in CRC patient tissues and cell lines using immunohistochemistry, quantitative real-time polymerase chain reaction, and western blotting. The biological functions of WWP2 were assessed using in vitro assays for cell proliferation, migration, and invasion following adenovirus-mediated overexpression. The molecular mechanism was investigated by analyzing the protein expression levels of p53 and its downstream target, p21, via western blot. An in vivo xenograft mouse model was used to confirm the oncogenic role of WWP2. Results: WWP2 expression was significantly upregulated in CRC tissues. Overexpression of WWP2 promoted CRC cell proliferation, migration, and invasion. Mechanistically, increased WWP2 expression led to a marked reduction in the protein levels of the tumor suppressor p53. Consequently, the expression of the p53 downstream target, the cell cycle inhibitor p21, was also suppressed. In the xenograft model, WWP2 overexpression significantly enhanced tumor growth. Conclusion Our findings demonstrate that WWP2 functions as an oncogene in CRC. It promotes cancer progression by destabilizing the tumor suppressor p53 and downregulating p21. This study highlights the WWP2-p53-p21 axis as a potential novel therapeutic target for CRC.