Cheung, Tan To

Objective: To establish benchmark cutoffs for robotic liver resection (R-LR), encompassing both major and minor resections, and to determine the impact of patient selection on outcomes. Background: R-LR is a key advancement in minimally invasive liver surgery but lacks standardized benchmarks, especially for minor resections. While guidelines endorse R-LR, its role in optimizing outcomes remains unclear. This study establishes the first benchmarks for R-LR, enabling comparisons across surgical modalities and refining patient selection. Methods: This retrospective, multicenter study analyzed consecutive adult patients undergoing R-LR at 30 international centers (2020–2023). Benchmark centers had an annual case volume of ≥15 R-LR. Benchmark criteria included ASA ≤2, no major comorbidities, no prior liver resections, and Child-Pugh A status. Benchmark cutoffs for 14 key outcomes were set at the 50th and 75th percentiles of median values across benchmark centers. Multivariable logistic regression identified predictors of textbook outcomes. Results: Eighteen high-volume centers contributed 4028 cases with 2632 (65.3%) meeting benchmark criteria. Malignancy was the indication in 29.6%, most commonly hepatocellular carcinoma followed by colorectal liver metastases. Major liver resection was performed in 42.6%. The distribution of Iwate difficulty scores was low (25.4%), intermediate (53.9%), advanced (15.9%), and expert (4.9%). Benchmark cutoffs were established for minor and major resection, and stratified by Iwate low (0-3), intermediate (4-6) and high (7-12): Open conversion (≤6.5% minor, ≤10.5% major), major complications within 90 days (≤5.2% minor, ≤16.7% major), R1 resection (≤9.2% minor, ≤6.7% major). Benchmark cases performed at low-volume centers were able to achieve outcomes within the corresponding benchmark cutoffs. In fact, patient selection reflected by the proportion of benchmark patients, rather than case volume, was associated with textbook outcomes. Conclusions: This study defines R-LR benchmarks, emphasizing patient selection over center volume for optimal outcomes. Benchmark cutoffs guide training and support the expansion of R-LR.

Abstract Background Robotic Whipple holds the promise to overcome safety concerns associated with laparoscopy, paving the way for widespread implementation of minimal-invasive surgery in this complex procedure. However, randomized data comparing robot vs. open Whipple demonstrate more pancreas-specific complications and R1-resections in the robotic arm. Recent international consensus identified establishing benchmarks as critical to ensure safe adoption of the robot. Benchmarking is a validated quality improvement tool, enabling comparison of surgical performance. Aims The aim was to define benchmarks for outcome parameters in robotic Whipple. Methods We analyzed consecutive patients undergoing robotic Whipple from January 2020 until December 2023 in 11 centers across 4 continents, with a minimum one-year follow-up. Centers had to perform ≥15 cases/year and have mounted their learning curve. Benchmark criteria included benign or resectable malignant disease without neoadjuvant therapy, arterial resection, major co-morbidities, or significant previous abdominal surgery. Medians across centers represented benchmark cutoffs. Results Eleven centers performed 1’037 Whipple procedures, of which 603 (58%) were benchmark cases. One third (n=192) were pancreatic ductal adenocarcinoma (PDAC) patients. Key benchmarks at 6 months included ≤1.2% mortality, ≤24.2% major complications, and ≤ 8.7 points Comprehensive Complication Index®. Pancreas-specific cutoffs included ≤13.0% postoperative pancreatic fistula (POPF) B/C and ≤3.4% post-pancreatectomy hemorrhage B/C, with 100% R0-resection and ≥19 harvested lymph nodes in PDAC patients. One-year actuarial overall and recurrence-free survival was 87% and 77%. In the entire cohort POPF B/C occurred in 16% (n=195). Independent POPF predictors included duct diameter ≤4mm (OR 1.79 95%CI [1.27-2.55]), anticoagulation (OR 3.68 95%CI [2.14-6.24]), and indication other than PDAC (OR 3.17, 95%CI [2.13-4.85]). Conclusion This study establishes benchmarks for key outcomes in robotic Whipple, demonstrating oncologic adequacy and morbidity comparable to open surgery. Risk factors for POPF in open surgery also hold true in the robotic approach.

AbstractBackgroundThis study investigates the impact of margin status after colorectal liver metastasis (CLM) resection on outcomes of patients after neoadjuvant treatment versus those who underwent upfront resection.MethodsAn international collaborative database of CLM patients who underwent surgical resection was used. Proportional hazard regression models were created for single and multivariable models to assess the relationship between independent measures and median overall survival (mOS).ResultsR1 was associated with worse OS in the neoadjuvant group (mOS: 51.8 m for R0 vs. 26.0 m for R1; HR: 2.18). In the patients who underwent upfront surgery, R1 was not associated with OS. (mOS: 46.7 m for R0 vs. 42.6 m for R1). When patients with R1 in each group were stratified by adjuvant treatment, there was no significant difference in the neoadjuvant group, while in the upfront surgery group with R1, adjuvant treatment was associated with significant improvement in OS (mOS: 42.6 m for adjuvant vs. 25.0 m for no adjuvant treatment; HR: 0.21).ConclusionR1 is associated with worse outcomes in the patients who receive neoadjuvant treatment with no significant improvement with the addition of adjuvant therapy, likely representing an aggressive tumor biology. R1 did not impact OS in patients with upfront surgery who received postoperative chemotherapy.

AbstractBackgroundThermal ablation has recently become a key therapy for the treatment of colorectal liver metastasis (CLM). However, the role of ablation in combination with resection has not yet been firmly established. We hypothesize that in patients with CLM, those who undergo liver resection with ablation (RA) have similar outcomes compared with those who undergo liver resection only.MethodsWe reviewed a multicenter international database of 906 surgical procedures for CLM from 5 high volume hepatobiliary surgical units. Patients undergoing RA (n = 63) were matched based on the number of lesions and tumor size using a 1:1 balanced propensity score analysis with those having resection only (n = 63). Our primary outcomes were overall survival (OS) and disease‐free survival (DFS).ResultsThe mean age of our cohort was 58 ± 11 years, with 43% females. With a median follow‐up of 70.8 months, patients in the resection and RA group had a median OS of 45.1 and 54.8 months (p = 0.71), respectively. The median DFS was 22.7 and 14.2 months (p = 0.045), respectively. Using a multivariate Cox proportional hazards regression model, the treatment approach was not associated with OS (p = 0.94) or DFS (p = 0.059). A higher number of lesions is independently associated with worse DFS (hazard ratio: 1.12, p < 0.01). When there was disease recurrence, the region of recurrence was similar between the RA versus resection only groups (p = 0.27), but there was a shorter time to recurrence in the RA group (p = 0.002).ConclusionFor CLM, the treatment approach was not significantly associated with OS or DFS, while tumor biology likely played an important role. Prospective research on the quality and effectiveness of thermal ablation combined with hepatic resection is warranted.

BACKGROUND: Surgical intervention remains the cornerstone of a multidisciplinary approach in the treatment of colorectal liver metastases (CLM). Nevertheless, patient outcomes vary greatly. While predictive tools can assist decision-making and patient counseling, decades of efforts have yet to result in generating a universally adopted tool in clinical practice. STUDY DESIGN: An international collaborative database of CLM patients who underwent surgical therapy between 2000 and 2018 was used to select 1,004 operations for this study. Two different machine learning methods were applied to construct 2 predictive models for recurrence and death, using 128 clinicopathologic variables: gradient-boosted trees (GBTs) and logistic regression with bootstrapping (LRB) in a leave-one-out cross-validation. RESULTS: Median survival after resection was 47.2 months, and disease-free survival was 19.0 months, with a median follow-up of 32.0 months in the cohort. Both models had good predictive power, with GBT demonstrating a superior performance in predicting overall survival (area under the receiver operating curve [AUC] 0.773, 95% CI 0.743 to 0.801 vs LRB: AUC 0.648, 95% CI 0.614 to 0.682) and recurrence (AUC 0.635, 95% CI 0.599 to 0.669 vs LRB: AUC 0.570, 95% CI 0.535 to 0.601). Similarly, better performances were observed predicting 3- and 5-year survival, as well as 3- and 5-year recurrence, with GBT methods generating higher AUCs. CONCLUSIONS: Machine learning provides powerful tools to create predictive models of survival and recurrence after surgery for CLM. The effectiveness of both machine learning models varies, but on most occasions, GBT outperforms LRB. Prospective validation of these models lays the groundwork to adopt them in clinical practice.

Background: In patients with neuroendocrine liver metastasis (NELM), liver transplantation (LT) is an alternative to liver resection (LR), although the choice of therapy remains controversial. In this multicenter study, we aim to provide novel insight in this dispute. Methods: Following a systematic literature search, 15 large international centers were contacted to provide comprehensive data on their patients after LR or LT for NELM. Survival analyses were performed with the Kaplan-Meier method, while multivariable Cox regression served to identify factors influencing survival after either transplantation or resection. Inverse probability weighting and propensity score matching was used for analyses with balanced and equalized baseline characteristics. Results: Overall, 455 patients were analyzed, including 230 after LR and 225 after LT, with a median follow-up of 97 months [95% confidence interval (CI): 85–110 months]. Multivariable analysis revealed G3 grading as a negative prognostic factor for LR [hazard ratio (HR)=2.22, 95% CI: 1.04–4.77, P=0.040], while G2 grading (HR=2.52, 95% CI: 1.15–5.52, P=0.021) and LT outside Milan criteria (HR=2.40, 95% CI: 1.16–4.92, P=0.018) were negative prognostic factors in transplanted patients. Inverse probability-weighted multivariate analyses revealed a distinct survival benefit after LT. Matched patients presented a median overall survival (OS) of 197 months (95% CI: 143–not reached) and a 73% 5-year OS after LT, and 119 months (95% CI: 74–133 months) and a 52.8% 5-year OS after LR (HR=0.59, 95% CI: 0.3–0.9, P=0.022). However, the survival benefit after LT was lost if patients were transplanted outside Milan criteria. Conclusions: This multicentric study in patients with NELM demonstrates a survival benefit of LT over LR. This benefit depends on adherence to selection criteria, in particular low-grade tumor biology and Milan criteria, and must be balanced against potential risks of LT.

AbstractBackgroundChemotherapy has been increasingly combined with surgery as multimodality treatment for resectable colorectal‐liver metastases (CLM). There is paucity of clinical data addressing optimal timing of chemotherapy relative to surgery. We examined outcomes of patients undergoing hepatectomy for resectable CLM.MethodsSeven hundred and eighteen patients treated with hepatectomy for CLM were analyzed from five hepatobiliary institutions between 2000 and 2018. Overall survival (OS) was measured from time of hepatectomy for patients receiving: surgery alone, neoadjuvant, adjuvant, and neoadjuvant‐plus‐adjuvant (perioperative) chemotherapy. Kaplan–Meier analysis was performed to detect differences in OS between treatment groups. Single‐ and multi‐variable analysis with Cox proportional hazards were run for OS between groups.ResultsOne hundred and thirty‐seven patients (19.08%) received surgery, 104 (14.48%) received neoadjuvant‐only, 214 (29.81%) received adjuvant‐only, and 263 (36.63%) received perioperative chemotherapy; with median OS of 48.20, 46.83, 56.27, and 49.93 months, respectively. No differences in median OS were seen between groups on Kaplan–Meier analysis. No significant difference in Charlson‐Deyo comorbidity status was seen between groups (p = 0.853), while significant difference was seen in maximum tumor size (p = 0.0023). On multivariate analysis, adjuvant (p = 0.010) and perioperative (p = 0.020) chemotherapy were independently associated with OS compared to surgery alone.DiscussionDespite group differences, chemotherapy after surgery was independently associated with improved OS in CLM.