Laparoscopic Versus Open Hemihepatectomy: The ORANGE II PLUS Multicenter Randomized Controlled Trial.

PURPOSE: To compare outcomes after laparoscopic versus open major liver resection (hemihepatectomy) mainly for primary or metastatic cancer. The primary outcome measure was time to functional recovery. Secondary outcomes included morbidity, quality of life (QoL), and for those with cancer, resection margin status and time to adjuvant systemic therapy. PATIENTS AND METHODS: This was a multicenter, randomized controlled, patient-blinded, superiority trial on adult patients undergoing hemihepatectomy. Patients were recruited from 16 hospitals in Europe between November 2013 and December 2018. RESULTS: Of the 352 randomly assigned patients, 332 patients (94.3%) underwent surgery (laparoscopic, n = 166 and open, n = 166) and comprised the analysis population. The median time to functional recovery was 4 days (IQR, 3-5; range, 1-30) for laparoscopic hemihepatectomy versus 5 days (IQR, 4-6; range, 1-33) for open hemihepatectomy (difference, -17.5% [96% CI, -25.6 to -8.4]; P < .001). There was no difference in major complications (laparoscopic 24/166 [14.5%] v open 28/166 [16.9%]; odds ratio [OR], 0.84; P = .58). Regarding QoL, both global health status (difference, 3.2 points; P < .001) and body image (difference, 0.9 points; P < .001) scored significantly higher in the laparoscopic group. For the 281 (84.6%) patients with cancer, R0 resection margin status was similar (laparoscopic 106 [77.9%] v open 122 patients [84.1%], OR, 0.60; P = .14) with a shorter time to adjuvant systemic therapy in the laparoscopic group (46.5 days v 62.8 days, hazard ratio, 2.20; P = .009). CONCLUSION: Among patients undergoing hemihepatectomy, the laparoscopic approach resulted in a shorter time to functional recovery compared with open surgery. In addition, it was associated with a better QoL, and in patients with cancer, a shorter time to adjuvant systemic therapy with no adverse impact on cancer outcomes observed.

Pan-European survey on current treatment strategies in patients with upfront resectable colorectal liver metastases.

BACKGROUND: There is a lack of consensus on the definition of upfront resectability and use of perioperative systemic therapy for colorectal liver metastases (CRLM). This survey aimed to summarize the current treatment strategies for upfront resectable CRLM throughout Europe. METHODS: A survey was sent to all members of the European-African Hepato-Pancreato-Biliary Association to gain insight into the current views on resectability and the use of systemic therapy for upfront resectable CRLM. RESULTS: The survey was completed by 87 surgeons from 24 countries. The resectability of CRLM is mostly based on the volume of the future liver remnant, while considering tumor biology. Thermal ablation was considered as an acceptable adjunct to resection in parenchymal-sparing CRLM surgery by 77 % of the respondents. A total of 40.2 % of the respondents preferred standard perioperative systemic therapy and 24.1 % preferred standard upfront local treatment. CONCLUSION: Among the participating European hepato-pancreato-biliary surgeons, there is a high degree of consensus on the definition of CRLM resectability. However, there is much variety in the use of adjunctive thermal ablation. Major variations persist in the use of perioperative systemic therapy in cases of upfront resectable CRLM, stressing the need for further evidence and a consensus.

MRI in addition to CT in patients scheduled for local therapy of colorectal liver metastases (CAMINO): an international, multicentre, prospective, diagnostic accuracy trial.

BACKGROUND: Guidelines are inconclusive on whether contrast-enhanced MRI using gadoxetic acid and diffusion-weighted imaging should be added routinely to CT in the investigation of patients with colorectal liver metastases who are scheduled for curative liver resection or thermal ablation, or both. Although contrast-enhanced MRI is reportedly superior than contrast-enhanced CT in the detection and characterisation of colorectal liver metastases, its effect on clinical patient management is unknown. We aimed to assess the clinical effect of an additional liver contrast-enhanced MRI on local treatment plan in patients with colorectal liver metastases amenable to local treatment, based on contrast-enhanced CT. METHODS: We did an international, multicentre, prospective, incremental diagnostic accuracy trial in 14 liver surgery centres in the Netherlands, Belgium, Norway, and Italy. Participants were aged 18 years or older with histological proof of colorectal cancer, a WHO performance status score of 0-4, and primary or recurrent colorectal liver metastases, who were scheduled for local therapy based on contrast-enhanced CT. All patients had contrast-enhanced CT and liver contrast-enhanced MRI including diffusion-weighted imaging and gadoxetic acid as a contrast agent before undergoing local therapy. The primary outcome was change in the local clinical treatment plan (decided by the individual clinics) on the basis of liver contrast-enhanced MRI findings, analysed in the intention-to-image population. The minimal clinically important difference in the proportion of patients who would have change in their local treatment plan due to an additional liver contrast-enhanced MRI was 10%. This study is closed and registered in the Netherlands Trial Register, NL8039. FINDINGS: Between Dec 17, 2019, and July 31, 2021, 325 patients with colorectal liver metastases were assessed for eligibility. 298 patients were enrolled and included in the intention-to-treat population, including 177 males (59%) and 121 females (41%) with planned local therapy based on contrast-enhanced CT. A change in the local treatment plan based on liver contrast-enhanced MRI findings was observed in 92 (31%; 95% CI 26-36) of 298 patients. Changes were made for 40 patients (13%) requiring more extensive local therapy, 11 patients (4%) requiring less extensive local therapy, and 34 patients (11%) in whom the indication for curative-intent local therapy was revoked, including 26 patients (9%) with too extensive disease and eight patients (3%) with benign lesions on liver contrast-enhanced MRI (confirmed by a median follow-up of 21·0 months [IQR 17·5-24·0]). INTERPRETATION: Liver contrast-enhanced MRI should be considered in all patients scheduled for local treatment for colorectal liver metastases on the basis of contrast-enhanced CT imaging. FUNDING: The Dutch Cancer Society and Bayer AG - Pharmaceuticals.

Propensity Score-Matching Analysis Comparing Robotic Versus Laparoscopic Limited Liver Resections of the Posterosuperior Segments: An International Multicenter Study.

OBJECTIVE: The purpose of this study was to compare the outcomes of robotic limited liver resections (RLLR) versus laparoscopic limited liver resections (LLLR) of the posterosuperior segments. BACKGROUND: Both laparoscopic and robotic liver resections have been used for tumors in the posterosuperior liver segments. However, the comparative performance and safety of both approaches have not been well examined in the existing literature. METHODS: This is a post hoc analysis of a multicenter database of 5446 patients who underwent RLLR or LLLR of the posterosuperior segments (I, IVa, VII, and VIII) at 60 international centers between 2008 and 2021. Data on baseline demographics, center experience and volume, tumor features, and perioperative characteristics were collected and analyzed. Propensity score-matching (PSM) analysis (in both 1:1 and 1:2 ratios) was performed to minimize selection bias. RESULTS: A total of 3510 cases met the study criteria, of whom 3049 underwent LLLR (87%), and 461 underwent RLLR (13%). After PSM (1:1: and 1:2), RLLR was associated with a lower open conversion rate [10 of 449 (2.2%) vs 54 of 898 (6.0%); P =0.002], less blood loss [100 mL [IQR: 50-200) days vs 150 mL (IQR: 50-350); P <0.001] and a shorter operative time (188 min (IQR: 140-270) vs 222 min (IQR: 158-300); P <0.001]. These improved perioperative outcomes associated with RLLR were similarly seen in a subset analysis of patients with cirrhosis-lower open conversion rate [1 of 136 (0.7%) vs 17 of 272 (6.2%); P =0.009], less blood loss [100 mL (IQR: 48-200) vs 160 mL (IQR: 50-400); P <0.001], and shorter operative time [190 min (IQR: 141-258) vs 230 min (IQR: 160-312); P =0.003]. Postoperative outcomes in terms of readmission, morbidity and mortality were similar between RLLR and LLLR in both the overall PSM cohort and cirrhosis patient subset. CONCLUSIONS: RLLR for the posterosuperior segments was associated with superior perioperative outcomes in terms of decreased operative time, blood loss, and open conversion rate when compared with LLLR.

The multi-societal European consensus on the terminology, diagnosis and management of patients with synchronous colorectal cancer and liver metastases: an E-AHPBA consensus in partnership with ESSO, ESCP, ESGAR, and CIRSE.

BACKGROUND: Contemporary management of patients with synchronous colorectal cancer and liver metastases is complex. The aim of this project was to provide a practical framework for care of patients with synchronous colorectal cancer and liver metastases with a focus on terminology, diagnosis and management. METHODS: This project was a multi-organisational, multidisciplinary consensus. The consensus group produced statements which focused on terminology, diagnosis and management. Statements were refined during an online Delphi process and those with 70% agreement or above were reviewed at a final meeting. Iterations of the report were shared by electronic mail to arrive at a final agreed document comprising twelve key statements. RESULTS: Synchronous liver metastases are those detected at the time of presentation of the primary tumour. The term "early metachronous metastases" applies to those absent at presentation but detected within 12 months of diagnosis of the primary tumour with "late metachronous metastases" applied to those detected after 12 months. Disappearing metastases applies to lesions which are no longer detectable on MR scan after systemic chemotherapy. Guidance was provided on the recommended composition of tumour boards and clinical assessment in emergency and elective settings. The consensus focused on treatment pathways including systemic chemotherapy, synchronous surgery and the staged approach with either colorectal or liver-directed surgery as first step. Management of pulmonary metastases and the role of minimally invasive surgery was discussed. CONCLUSIONS: The recommendations of this contemporary consensus provide information of practical value to clinicians managing patients with synchronous colorectal cancer and liver metastases.

Learning Curves of Minimally Invasive Distal Pancreatectomy in Experienced Pancreatic Centers.

Importance: Understanding the learning curve of a new complex surgical technique helps to reduce potential patient harm. Current series on the learning curve of minimally invasive distal pancreatectomy (MIDP) are mostly small, single-center series, thus providing limited data. Objective: To evaluate the length of pooled learning curves of MIDP in experienced centers. Design, Setting, and Participants: This international, multicenter, retrospective cohort study included MIDP procedures performed from January 1, 2006, through June 30, 2019, in 26 European centers from 8 countries that each performed more than 15 distal pancreatectomies annually, with an overall experience exceeding 50 MIDP procedures. Consecutive patients who underwent elective laparoscopic or robotic distal pancreatectomy for all indications were included. Data were analyzed between September 1, 2021, and May 1, 2022. Exposures: The learning curve for MIDP was estimated by pooling data from all centers. Main Outcomes and Measures: The learning curve was assessed for the primary textbook outcome (TBO), which is a composite measure that reflects optimal outcome, and for surgical mastery. Generalized additive models and a 2-piece linear model with a break point were used to estimate the learning curve length of MIDP. Case mix-expected probabilities were plotted and compared with observed outcomes to assess the association of changing case mix with outcomes. The learning curve also was assessed for the secondary outcomes of operation time, intraoperative blood loss, conversion to open rate, and postoperative pancreatic fistula grade B/C. Results: From a total of 2610 MIDP procedures, the learning curve analysis was conducted on 2041 procedures (mean [SD] patient age, 58 [15.3] years; among 2040 with reported sex, 1249 were female [61.2%] and 791 male [38.8%]). The 2-piece model showed an increase and eventually a break point for TBO at 85 procedures (95% CI, 13-157 procedures), with a plateau TBO rate at 70%. The learning-associated loss of TBO rate was estimated at 3.3%. For conversion, a break point was estimated at 40 procedures (95% CI, 11-68 procedures); for operation time, at 56 procedures (95% CI, 35-77 procedures); and for intraoperative blood loss, at 71 procedures (95% CI, 28-114 procedures). For postoperative pancreatic fistula, no break point could be estimated. Conclusion and Relevance: In experienced international centers, the learning curve length of MIDP for TBO was considerable with 85 procedures. These findings suggest that although learning curves for conversion, operation time, and intraoperative blood loss are completed earlier, extensive experience may be needed to master the learning curve of MIDP.

Transatlantic registries for minimally invasive liver surgery: towards harmonization.

BACKGROUND: Several registries focus on patients undergoing minimally invasive liver surgery (MILS). This study compared transatlantic registries focusing on the variables collected and differences in baseline characteristics, indications, and treatment in patients undergoing MILS. Furthermore, key variables were identified. METHODS: The five registries for liver surgery from North America (ACS-NSQIP), Italy, Norway, the Netherlands, and Europe were compared. A set of key variables were established by consensus expert opinion and compared between the registries. Anonymized data of all MILS procedures were collected (January 2014-December 2019). To summarize differences for all patient characteristics, treatment, and outcome, the relative and absolute largest differences (RLD, ALD) between the smallest and largest outcome per variable among the registries are presented. RESULTS: In total, 13,571 patients after MILS were included. Both 30- and 90-day mortality after MILS were below 1.1% in all registries. The largest differences in baseline characteristics were seen in ASA grade 3-4 (RLD 3.0, ALD 46.1%) and the presence of liver cirrhosis (RLD 6.4, ALD 21.2%). The largest difference in treatment was the use of neoadjuvant chemotherapy (RLD 4.3, ALD 20.6%). The number of variables collected per registry varied from 28 to 303. From the 46 key variables, 34 were missing in at least one of the registries. CONCLUSION: Despite considerable variation in baseline characteristics, indications, and treatment of patients undergoing MILS in the five transatlantic registries, overall mortality after MILS was consistently below 1.1%. The registries should be harmonized to facilitate future collaborative research on MILS for which the identified 46 key variables will be instrumental.

Laparoscopic versus open liver resection for intrahepatic cholangiocarcinoma: a multicenter propensity score-matched study.

BACKGROUND: The role of laparoscopy in the treatment of intrahepatic cholangiocarcinoma (ICC) remains unclear. This multicenter study examined the outcomes of laparoscopic liver resection for ICC. METHODS: Patients with ICC who had undergone laparoscopic or open liver resection between 2012 and 2019 at four European expert centers were included in the study. Laparoscopic and open approaches were compared in terms of surgical and oncological outcomes. Propensity score matching was used for minimizing treatment selection bias and adjusting for confounders (age, ASA grade, tumor size, location, number of tumors and underlying liver disease). RESULTS: Of 136 patients, 50 (36.7%) underwent laparoscopic resection, whereas 86 (63.3%) had open surgery. Median tumor size was larger (73.6 vs 55.1 mm, p = 0.01) and the incidence of bi-lobar tumors was higher (36.6 vs 6%, p < 0.01) in patients undergoing open surgery. After propensity score matching baseline characteristics were comparable although open surgery was associated with a larger fraction of major liver resections (74 vs 38%, p < 0.01), lymphadenectomy (60 vs 20%, p < 0.01) and longer operative time (294 vs 209 min, p < 0.01). Tumor characteristics were similar. Laparoscopic resection resulted in less complications (30 vs 52%, p = 0.025), fewer reoperations (4 vs 16%, p = 0.046) and shorter hospital stay (5 vs 8 days, p < 0.01). No differences were found in terms of recurrence, recurrence-free and overall survival. CONCLUSION: Laparoscopic resection seems to be associated with improved short-term and with similar long-term outcomes compared with open surgery in patients with ICC. However, possible selection criteria for laparoscopic surgery are yet to be defined.

Defining Global Benchmarks for Laparoscopic Liver Resections: An International Multicenter Study.

OBJECTIVE: To establish global benchmark outcomes indicators after laparoscopic liver resections (L-LR). BACKGROUND: There is limited published data to date on the best achievable outcomes after L-LR. METHODS: This is a post hoc analysis of a multicenter database of 11,983 patients undergoing L-LR in 45 international centers in 4 continents between 2015 and 2020. Three specific procedures: left lateral sectionectomy (LLS), left hepatectomy (LH), and right hepatectomy (RH) were selected to represent the 3 difficulty levels of L-LR. Fifteen outcome indicators were selected to establish benchmark cutoffs. RESULTS: There were 3519 L-LR (LLS, LH, RH) of which 1258 L-LR (40.6%) cases performed in 34 benchmark expert centers qualified as low-risk benchmark cases. These included 659 LLS (52.4%), 306 LH (24.3%), and 293 RH (23.3%). The benchmark outcomes established for operation time, open conversion rate, blood loss ≥500 mL, blood transfusion rate, postoperative morbidity, major morbidity, and 90-day mortality after LLS, LH, and RH were 209.5, 302, and 426 minutes; 2.1%, 13.4%, and 13.0%; 3.2%, 20%, and 47.1%; 0%, 7.1%, and 10.5%; 11.1%, 20%, and 50%; 0%, 7.1%, and 20%; and 0%, 0%, and 0%, respectively. CONCLUSIONS: This study established the first global benchmark outcomes for L-LR in a large-scale international patient cohort. It provides an up-to-date reference regarding the "best achievable" results for L-LR for which centers adopting L-LR can use as a comparison to enable an objective assessment of performance gaps and learning curves.

Laparoscopic parenchyma-sparing liver resection for large (≥ 50 mm) colorectal metastases.

BACKGROUND: Traditionally, patients with large liver tumors (≥ 50 mm) have been considered for anatomic major hepatectomy. Laparoscopic resection of large liver lesions is technically challenging and often performed by surgeons with extensive experience. The current study aimed to evaluate the surgical and oncologic safety of laparoscopic parenchyma-sparing liver resection in patients with large colorectal metastases. METHODS: Patients who primarily underwent laparoscopic parenchyma-sparing liver resection (less than 3 consecutive liver segments) for colorectal liver metastases between 1999 and 2019 at Oslo University Hospital were analyzed. In some recent cases, a computer-assisted surgical planning system was used to better visualize and understand the patients' liver anatomy, as well as a tool to further improve the resection strategy. The surgical and oncologic outcomes of patients with large (≥ 50 mm) and small (< 50 mm) tumors were compared. Multivariable Cox-regression analysis was performed to identify risk factors for survival. RESULTS: In total 587 patients met the inclusion criteria (large tumor group, n = 59; and small tumor group, n = 528). Median tumor size was 60 mm (range, 50-110) in the large tumor group and 21 mm (3-48) in the small tumor group (p < 0.001). Patient age and CEA level were higher in the large tumor group (8.4 µg/L vs. 4.6 µg/L, p < 0.001). Operation time and conversion rate were similar, while median blood loss was higher in the large tumor group (500 ml vs. 200 ml, p < 0.001). Patients in the large tumor group had shorter 5 year overall survival (34% vs 49%, p = 0.027). However, in the multivariable Cox-regression analysis tumor size did not impact survival, unlike parameters such as age, ASA score, CEA level, extrahepatic disease at liver surgery, and positive lymph nodes in the primary tumor. CONCLUSION: Laparoscopic parenchyma-sparing resections for large colorectal liver metastases provide satisfactory short and long-term outcomes.

Long-term oncological outcomes after laparoscopic parenchyma-sparing redo liver resections for patients with metastatic colorectal cancer: a European multi-center study.

BACKGROUND: Laparoscopic redo resections for colorectal metastases are poorly investigated. This study aims to explore long-term results after second, third, and fourth resections. MATERIAL AND METHODS: Prospectively updated databases of primary and redo laparoscopic liver resections in six European HPB centers were analyzed. Procedure-related overall survival after first, second, third, and fourth resections were evaluated. Furthermore, patients without liver recurrence after first liver resection were compared to those with one redo, two or three redo, and patients with palliative treatment for liver recurrence after first laparoscopic liver surgery. Survival was calculated both from the date of the first liver resection and from the date of the actual liver resection. In total, 837 laparoscopic primary and redo liver resections performed in 762 patients were included (630 primary, 172 first redo, 29 second redo, and 6 third redo). Patients were bunched into four groups: Group 1-without hepatic recurrence after primary liver resection (n = 441); Group 2-with liver recurrence who underwent only one laparoscopic redo resection (n = 154); Group 3-with liver recurrence who underwent two laparoscopic redo resections (n = 29); Group 4-with liver recurrence who have not been found suitable for redo resections (n = 138). RESULTS: No significant difference has been found between the groups in terms of baseline characteristics and surgical outcomes. Rate of positive resection margin was higher in the group with palliative recurrence (group 4). Five-year survival calculated from the first liver resection was 67%, 62%, 84%, and 7% for group 1, 2, 3, and 4, respectively. Procedure-specific 5-year overall survival was 50% after primary laparoscopic liver resection, 52% after the 1st reoperation, 52% after the 2nd, and 40% after the 3rd reoperation made laparoscopic. CONCLUSIONS: Multiple redo recurrences can be performed laparoscopically with good long-term results. Liver recurrence does not aggravate prognosis as long as the patient is suitable for reoperation.

Sarcopenia predicts reduced liver growth and reduced resectability in patients undergoing portal vein embolization before liver resection - A DRAGON collaborative analysis of 306 patients.

BACKGROUND: After portal vein embolization (PVE) 30% fail to achieve liver resection. Malnutrition is a modifiable risk factor and can be assessed by radiological indices. This study investigates, if sarcopenia affects resectability and kinetic growth rate (KGR) after PVE. METHODS: A retrospective study was performed of the outcome of PVE at 8 centres of the DRAGON collaborative from 2010 to 2019. All malignant tumour types were included. Sarcopenia was defined using gender, body mass and skeletal muscle index. First imaging after PVE was used for liver volumetry. Primary and secondary endpoints were resectability and KGR. Risk factors impacting liver growth were assessed in a multivariable analysis. RESULTS: Eight centres identified 368 patients undergoing PVE. 62 patients (17%) had to be excluded due to unavailability of data. Among the 306 included patients, 112 (37%) were non-sarcopenic and 194 (63%) were sarcopenic. Sarcopenic patients had a 21% lower resectability rate (87% vs. 66%, p < 0.001) and a 23% reduced KGR (p = 0.02) after PVE. In a multivariable model dichotomized for KGR ≥2.3% standardized FLR (sFLR)/week, only sarcopenia and sFLR before embolization correlated with KGR. CONCLUSION: In this largest study of risk factors, sarcopenia was associated with reduced resectability and KGR in patients undergoing PVE.

T cell receptor repertoire sequencing reveals chemotherapy-driven clonal expansion in colorectal liver metastases.

BACKGROUND: Colorectal liver metastasis (CLM) is a leading cause of colorectal cancer mortality, and the response to immune checkpoint inhibition (ICI) in microsatellite-stable CRC has been disappointing. Administration of cytotoxic chemotherapy may cause increased density of tumor-infiltrating T cells, which has been associated with improved response to ICI. This study aimed to quantify and characterize T-cell infiltration in CLM using T-cell receptor (TCR) repertoire sequencing. Eighty-five resected CLMs from patients included in the Oslo CoMet study were subjected to TCR repertoire sequencing. Thirty-five and 15 patients had received neoadjuvant chemotherapy (NACT) within a short or long interval, respectively, prior to resection, while 35 patients had not been exposed to NACT. T-cell fractions were calculated, repertoire clonality was analyzed based on Hill evenness curves, and TCR sequence convergence was assessed using network analysis. RESULTS: Increased T-cell fractions (10.6% vs. 6.3%) were detected in CLMs exposed to NACT within a short interval prior to resection, while modestly increased clonality was observed in NACT-exposed tumors independently of the timing of NACT administration and surgery. While private clones made up >90% of detected clones, network connectivity analysis revealed that public clones contributed the majority of TCR sequence convergence. CONCLUSIONS: TCR repertoire sequencing can be used to quantify T-cell infiltration and clonality in clinical samples. This study provides evidence to support chemotherapy-driven T-cell clonal expansion in CLM in a clinical context.

Laparoscopic liver resection with simultaneous diaphragm resection.

BACKGROUND: Liver resection or ablation remains the only curative treatment for patients with colorectal metastases. Simultaneous resection of tumors in the liver with invasion to the diaphragm is challenging and controversial. Therefore, we wanted to assess the safety of simultaneous laparoscopic liver and diaphragm resection (SLLDR) in a large single center. METHODS: Patients who underwent primary laparoscopic liver resection (LLR) for colorectal liver metastases at Oslo University Hospital between 2008 and 2019 were included in this study. Patients who underwent SLLDR (group 1) were compared to patients who underwent LLR only (group 2). Perioperative and oncologic outcomes were analyzed. RESULTS: A total of 467 patients were identified, of whom 12 patients needed a simultaneous diaphragm resection (group 1) while 455 underwent laparoscopic liver surgery alone (group 2). The conversion rate was 16.7% in group 1 and 2.4% in group 2 (P=0.040). In 10 of 12 (83.3%) cases the diaphragm resection was performed en bloc with the liver tumor. There was no significant difference in operative time, blood loss, resection margins, hospital stay or postoperative complications. One patient died within 30 postoperative days (0.2%) in group 2 and none in group 1. Overall survival was not statistically different between the groups. CONCLUSIONS: In selected patients, SLLDR can be performed safely with good surgical and oncological outcomes.

Use of mixed reality for improved spatial understanding of liver anatomy.

Introduction: In liver surgery, medical images from pre-operative computed tomography and magnetic resonance imaging are the basis for the decision-making process. These images are used in surgery planning and guidance, especially for parenchyma-sparing hepatectomies. Though medical images are commonly visualized in two dimensions (2D), surgeons need to mentally reconstruct this information in three dimensions (3D) for a spatial understanding of the anatomy. The aim of this work is to investigate whether the use of a 3D model visualized in mixed reality with Microsoft HoloLens increases the spatial understanding of the liver, compared to the conventional way of using 2D images.Material and methods: In this study, clinicians had to identify liver segments associated to lesions.Results: Twenty-eight clinicians with varying medical experience were recruited for the study. From a total of 150 lesions, 89 were correctly assigned without significant difference between the modalities. The median time for correct identification was 23.5 [4-138] s using the magnetic resonance imaging images and 6.00 [1-35] s using HoloLens (p < 0.001).Conclusions: The use of 3D liver models in mixed reality significantly decreases the time for tasks requiring a spatial understanding of the organ. This may significantly decrease operating time and improve use of resources.

Laparoscopic versus open liver resection in the posterosuperior segments: a sub-group analysis from the OSLO-COMET randomized controlled trial.

BACKGROUND: Laparoscopic liver resection in the posterosuperior segments is technically challenging. This study aimed to compare the perioperative outcomes for laparoscopic and open resection of colorectal liver metastases located in the posterosuperior segments. METHODS: This was a subgroup analysis of the OSLO-COMET randomized controlled trial, where 280 patients were randomly assigned to open or laparoscopic parenchyma-sparing liver resections of colorectal metastases. Patients with tumors in the posterosuperior segments were identified, and perioperative outcomes and health related quality of life (HRQoL) were compared. RESULTS: We identified a total of 136 patients, 62 in the laparoscopic and 74 in the open group. The postoperative complication rate was 26% in the laparoscopic and 31% in the open group. The blood loss was less in the open group (500 vs. 250 ml, P = 0.006), but the perioperative transfusion rate was similar. The operative time was similar, while postoperative hospital stay was shorter in the laparoscopic group (2 vs. 4 days, P < 0.001). HRQoL was significantly better after laparoscopy at 1 month. CONCLUSION: In patients undergoing laparoscopic or open liver resection of colorectal liver metastases in the posterosuperior segments, laparoscopic surgery was associated with shorter hospital stay and comparable perioperative outcomes.

RAS Mutation Clinical Risk Score to Predict Survival After Resection of Colorectal Liver Metastases.

OBJECTIVE: To determine the impact of RAS mutation status on the traditional clinical score (t-CS) to predict survival after resection of colorectal liver metastases (CLM). BACKGROUND: The t-CS relies on the following factors: primary tumor nodal status, disease-free interval, number and size of CLM, and carcinoembryonic antigen level. We hypothesized that the addition of RAS mutation status could create a modified clinical score (m-CS) that would outperform the t-CS. METHODS: Patients who underwent resection of CLM from 2005 through 2013 and had RAS mutation status and t-CS factors available were included. Multivariate analysis was used to identify prognostic factors to include in the m-CS. Log-rank survival analyses were used to compare the t-CS and the m-CS. The m-CS was validated in an international multicenter cohort of 608 patients. RESULTS: A total of 564 patients were eligible for analysis. RAS mutation was detected in 205 (36.3%) of patients. On multivariate analysis, RAS mutation was associated with poor overall survival, as were positive primary tumor lymph node status and diameter of the largest liver metastasis >50 mm. Each factor was assigned 1 point to produce a m-CS. The m-CS accurately stratified patients by overall and recurrence-free survival in both the initial patient series and validation cohort, whereas the t-CS did not. CONCLUSIONS: Modifying the t-CS by replacing disease-free interval, number of metastases, and CEA level with RAS mutation status produced an m-CS that outperformed the t-CS. The m-CS is therefore a simple validated tool that predicts survival after resection of CLM.