Purpose: Technological advancements have enabled reduced-port robotic systems, enhancing the benefits of robotic surgery. This study compared the surgical outcomes of conventional multiport (5 ports), single-site (2 ports), and singleport (2 ports) robotic gastrectomy for gastric cancer. Methods: A prospectively collected database was retrospectively reviewed for patients who underwent robotic distal subtotal gastrectomy between January 2010 and August 2022 at Severance Hospital, Yonsei University Health System. The initial 20 cases from each group (multiport, single-site, and SP) were analyzed, focusing on demographics, surgical procedures, pathological results, and postoperative outcomes. The “textbook outcome” metric was employed to assess surgical quality. Results: The SP group showed lower visual analog pain scale compared to the multiport and single-site groups (3.5, 4.4, and 4.3, respectively, P = 0.017), faster time to first flatus (2.0, 2.7, and 2.8 days, respectively; P < 0.001), and shorter hospital stays (3.5, 6.2, and 5.5 days, respectively; P < 0.001). No significant differences were observed in major complications, unplanned intensive care unit care, readmission, or mortality between the groups. The rate of patients achieving textbook outcomes were 85.0% for the multiport group, 100% for the single-site group, and 95.0% for the SP group (P = 0.310). Conclusion Reduced-port robotic gastrectomy, including single-site and SP, has shown surgical safety with a high proportion of patients meeting textbook outcomes. The SP system demonstrated less pain and faster recovery, aligning with minimally invasive surgical goals. Therefore, the SP system could be a reliable and safe option for robotic gastrectomy, offering enhanced recovery without compromising surgical quality.

Purpose: This study was performed to predict individualized treatment strategies in ruptured abdominal aortic aneurysm (rAAA) by estimating the survival benefit of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) based on anatomical and physiological features using a causal inference model. Methods: This retrospective study included 45 patients with de novo rAAA who underwent EVAR or OSR between 2012 and 2024. Thirty-three variables were analyzed. The model estimated individualized treatment effects (ITE) for 30-day survival.Model interpretability was assessed using Shapley Additive Explanations (SHAP) analysis. Five-fold cross-validation, receiver operating characteristic (ROC) analysis, and calibration plots were used for model evaluation. A clinical decision tree was developed to derive simplified decision rules. Results: The mean ITE was 0.22 ± 0.42, with 33% of patients classified as OSR-benefit candidates. SHAP analysis revealed that suprarenal angle, infrarenal angle, iliac anatomy, and proximal neck characteristics strongly influenced treatment effects. However, some predictors, such as low hemoglobin and systolic blood pressure favoring OSR, conflicted with clinical intuition. ROC analysis showed an area under the curve of 1.00, but calibration suggested overfitting due to a small sample size. Treatment-matched patients had a higher 30-day mortality rate than mismatched patients, suggesting potential bias or unmeasured confounding. The decision tree identified clinically relevant features but displayed structural inconsistencies and impractical cutoff values due to the limited sample size. Conclusion The X-learner model demonstrated the feasibility of individualized treatment prediction in rAAA but suffered from overfitting and limited generalizability. Validation with larger multicenter cohorts is necessary to confirm clinical applicability.

Purpose: Conventional multiport laparoscopic cholecystectomy (CMLC) is the gold standard for benign gallbladder disease. Single-incision laparoscopic cholecystectomy (SILC) offers superior cosmesis but has limited adoption due to technical challenges. We introduce the Ewha Method, a modified SILC technique using an articulating instrument to improve visualization, ergonomics, and safety. Methods: We retrospectively analyzed 530 patients who underwent SILC between November 2023 and August 2024.Surgical outcomes were compared between senior (n = 338) and junior (n = 192) surgeons. Difficult surgery (DS) was defined as conversion to CMLC or operative time >60 minutes. Multivariable analysis identified risk factors for DS, and the learning curve was evaluated. Results: The junior surgeon group included more high-risk patients, with higher proportions of elderly (≥65 years, 42.2% vs. 12.7%), male (53.6% vs. 29.9%), comorbidities, preoperative percutaneous transhepatic gallbladder drainage (PTGBD;30.7% vs. 0.0%), and gangrenous cholecystitis (7.3% vs. 0.3%). The conversion rate was higher for junior surgeons (10.4% vs. 0.3%), but the severe complication rate was similar (0.5% vs. 0.0%). No bile duct injuries or incisional hernias occurred.Independent predictors of DS included diabetes mellitus (hazard ratio [HR], 4.045), preoperative PTGBD (HR, 5.780), leukocytosis (HR, 7.457), impacted stones (HR, 7.913), and gangrenous cholecystitis (HR, 38.736). The learning curve plateaued after 38 cases in low-risk patients. Conclusion The Ewha Method standardizes SILC, ensuring safety and efficiency with a short learning curve and minimal complications. It may serve as a viable alternative to CMLC, warranting further validation in diverse clinical settings.

Purpose: Enhanced Recovery After Surgery (ERAS) protocols have demonstrated significant benefits, but their safety and effectiveness in high-risk patients remain unclear. This study evaluated clinical postoperative outcomes in elderly patients and those with comorbidities undergoing colon cancer surgery. Methods: This retrospective cohort study included 1,035 patients who underwent elective colon cancer surgery from 2017 to 2022. A standardized 25-element ERAS protocol was implemented across all groups. Patients were categorized into a control group (aged <70 years without comorbidities, n = 534) and high-risk groups including elderly patients (≥70 years, n = 312) and those with cardiac (n = 60), pulmonary (n = 81), renal (n = 24), or hepatic disease (n = 24). Results: ERAS compliance rates were significantly lower in all high-risk groups compared to controls (79.39% ± 10.9%), with renal disease patients showing the most pronounced reduction (69.69% ± 17.0%). Post-hoc analysis revealed that only renal disease patients demonstrated significantly higher complication rates (45.8% vs. 18.9%, P < 0.01). Despite lower compliance, multivariate analysis revealed ERAS compliance ≥70% as the strongest independent predictor of both length of stay (odds ratio [OR], 0.139; P < 0.001) and complications (OR, 0.298; P < 0.001), substantially outweighing patient risk factors. After adjusting for treatment factors, patient comorbidity groups showed no independent association with clinical outcomes. Conclusion ERAS protocols can be successfully implemented in high-risk patients with appropriate attention to compliance optimization. Treatment factors, particularly ERAS adherence, consistently outweigh patient risk factors in determining outcomes, and well-tailored ERAS implementation should be considered with high-risk patients for perioperative care.

Purpose: Due to its rarity, treatment guidelines for appendiceal cancer have traditionally followed those established for colorectal cancer, despite showing distinct histologic and clinical features. This study aimed to compare the clinicopathologic characteristics and long-term oncologic outcomes of appendiceal cancer with those of right-sided colon cancers. Methods: We retrospectively reviewed the records of patients with stage I–III appendiceal, cecal, or ascending colon cancer who underwent curative resection between 2010 and 2020 at our center. A 1:3:3 exact matching for age, sex, TNM stage, and adjuvant chemotherapy was performed. Survival outcomes were analyzed using the Kaplan-Meier and Cox regression methods. Results: Overall, 245 patients with appendiceal cancer (n = 35), ascending colon cancer (n = 105), and cecal cancer (n = 105) were analyzed. Appendiceal cancer exhibited a higher proportion of T4 tumors and fewer harvested lymph nodes compared with ascending or cecal cancers. The mean follow-up duration was 9.5 years. The 5- and 10-year overall survival rates were lower in appendiceal cancer (66.2% and 52.9%) than in ascending (91.2% and 78.4%) or cecal cancer (88.5% and 78.3%). Similarly, the 10-year disease-free survival rate was lower in appendiceal cancer (59.2%) compared with ascending (83.1%) and cecal cancers (78.4%). Cox regression analysis identified age (≥65 years), perforation, nodal metastasis, and lymphovascular invasion as independent predictors of poor prognosis. Conclusion Appendiceal cancer exhibited significantly worse long-term survival compared to cecal or ascending colon cancer. Tumor perforation, nodal metastasis, and lymphovascular invasion were adverse prognostic factors for overall and disease-free survival.

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.

Phyllodes tumors are rare biphasic fibroepithelial breast neoplasms classified as benign, borderline, or malignant. Despite their rarity, malignant variants carry higher risks of recurrence and metastasis. This review synthesizes current evidence on their clinical, histopathological, and molecular characteristics, including treatment strategies and prognostic factors, emphasizing tailored management. We performed a comprehensive literature review to summarize knowledge on clinical presentation, imaging, histopathological features, surgical treatment, adjuvant therapy, and outcomes. Recent genomic and molecular research was also evaluated to identify future directions. Persistent challenges include a lack of consensus on optimal surgical margins, adjuvant radiotherapy, and follow-up protocols, highlighting the need for larger, high-quality studies. Advances in molecular profiling suggest potential for targeted therapies, especially in aggressive or metastatic cases. Due to clinical heterogeneity and the limited accuracy of core biopsies, definitive grading based on surgical histopathology remains essential for treatment planning. This review offers an updated perspective on phyllodes tumor management, identifies critical gaps, and suggests priorities for future research.

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.