Impact of resection margins for colorectal liver metastases in laparoscopic and open liver resection: a propensity score analysis

ICG-Fluorescence Imaging for Margin Assessment During Minimally Invasive Colorectal Liver Metastasis Resection

Importance

Unintended tumor-positive resection margins occur frequently during minimally invasive surgery for colorectal liver metastases and potentially negatively influence oncologic outcomes.

Objective

To assess whether indocyanine green (ICG)-fluorescence-guided surgery is associated with achieving a higher radical resection rate in minimally invasive colorectal liver metastasis surgery and to assess the accuracy of ICG fluorescence for predicting the resection margin status.

Design, Setting, and Participants

The MIMIC (Minimally Invasive, Indocyanine-Guided Metastasectomy in Patients With Colorectal Liver Metastases) trial was designed as a prospective single-arm multicenter cohort study in 8 Dutch liver surgery centers. Patients were scheduled to undergo minimally invasive (laparoscopic or robot-assisted) resections of colorectal liver metastases between September 1, 2018, and June 30, 2021.

Exposures

All patients received a single intravenous bolus of 10 mg of ICG 24 hours prior to surgery. During surgery, ICG-fluorescence imaging was used as an adjunct to ultrasonography and regular laparoscopy to guide and assess the resection margin in real time. The ICG-fluorescence imaging was performed during and after liver parenchymal transection to enable real-time assessment of the tumor margin. Absence of ICG fluorescence was favorable both during transection and in the tumor bed directly after resection.

Main Outcomes and Measures

The primary outcome measure was the radical (R0) resection rate, defined by the percentage of colorectal liver metastases resected with at least a 1 mm distance between the tumor and resection plane. Secondary outcomes were the accuracy of ICG fluorescence in detecting margin-positive (R1; <1 mm margin) resections and the change in surgical management.

Results

In total, 225 patients were enrolled, of whom 201 (116 [57.7%] male; median age, 65 [IQR, 57-72] years) with 316 histologically proven colorectal liver metastases were included in the final analysis. The overall R0 resection rate was 92.4%. Re-resection of ICG-fluorescent tissue in the resection cavity was associated with a 5.0% increase in the R0 percentage (from 87.4% to 92.4%; P < .001). The sensitivity and specificity for real-time resection margin assessment were 60% and 90%, respectively (area under the receiver operating characteristic curve, 0.751; 95% CI, 0.668-0.833), with a positive predictive value of 54% and a negative predictive value of 92%. After training and proctoring of the first procedures, participating centers that were new to the technique had a comparable false-positive rate for predicting R1 resections during the first 10 procedures (odds ratio, 1.36; 95% CI, 0.44-4.24). The ICG-fluorescence imaging was associated with changes in intraoperative surgical management in 56 (27.9%) of the patients.

Conclusions and Relevance

In this multicenter prospective cohort study, ICG-fluorescence imaging was associated with an increased rate of tumor margin-negative resection and changes in surgical management in more than one-quarter of the patients. The absence of ICG fluorescence during liver parenchymal transection predicted an R0 resection with 92% accuracy. These results suggest that use of ICG fluorescence may provide real-time feedback of the tumor margin and a higher rate of complete oncologic resection.

Laparoscopic and Open Liver Resections for Colorectal Cancer Liver Metastasis in the Ukrainian State Center

Background Minimally invasive liver resections for metastatic colorectal cancer have been increasingly performed all over the world with promising results. We planned the current study to review our experience on this matter and compare short- and long-term outcomes of laparoscopic liver resection (LLR) and open liver resection (OLR) in patients with colorectal cancer liver metastasis (CRLM). Materials and methods This is a single-center retrospective analysis of patients with CRLM who underwent laparoscopic (n=86) and open (n=96) surgical treatment for metastatic liver lesions between March 2016 and November 2022. Tumor characteristics, intra- and postoperative results, overall survival (OS), and disease-free survival (DFS) were analyzed and compared. Results LLR was associated with significantly shorter surgery duration (180 minutes versus 295 minutes, p=0.03). There was no significant difference in blood loss between the two groups (100 mL versus 350 mL, p=0.061). Additionally, the laparoscopic approach was associated with significantly shorter hospital stays (6 days versus 9 days, p=0.004). The rate of major complications (Clavien-Dindo classification ≥ 3) was lower in the LLR group (5.8% versus 16.6%, p=0.037). There was no mortality in the LLR group, and in the OLR group, one lethal case was induced by mesenteric thrombosis on the fifth postoperative day. We did not find a statistically significant difference in the OS rate between the two groups at one, three, and five years: 97.3%, 74.7%, and 43.4%, respectively, in the OLR group and 95.1%, 70.3%, and 49.5%, respectively, in the LLR group (p=0.53). DFS at one, three, and five years were 88.7%, 52.3%, and 25.5%, respectively, in the LLR group and 71.9%, 53.1%, and 19.3%, respectively, in the OLR group (p=0.66). Conclusions This study showed that laparoscopic liver surgery is a safe and effective method of CRLM treatment in our center. LLR was associated with a decrease in major morbidity, shorter surgery duration, and reduced postoperative hospital stay. Minimally invasive liver resections showed similar oncological outcomes to the open approach in terms of overall and disease-free survival.

Long-term oncological outcomes for HALS/Hybrid vs pure laparoscopic approach in colorectal liver metastases: a propensity score matched analysis

BACKGROUND

Studies comparing hand-assisted laparoscopic (HALS)/Hybrid and pure laparoscopic (PLS) resection for colorectal cancer liver metastasis have focused on short-term results, while long-term oncological outcomes remain understudied.

METHODS

We established a multi-institutional retrospective cohort study from four centers with experience in minimally invasive surgery between 2004 and 2020. Primary endpoints were overall survival (OS) and disease-free survival (DFS). Other endpoints analyzed were intraoperative and postoperative outcomes. Propensity score matching (PSM) was used to minimize baseline differences.

RESULTS

A total of 219 HALS/Hybrid (57.8%) and 160 PLS (42.2%) patients were included. After PSM, 155 patients remained in each group. Operative time (182 vs. 248 min, p = 0.012), use of intraoperative ablation (12.3 vs. 4.5%, p = 0.024), positive resection margin (4.5 vs 13.2%, p = 0.012), and pringle time (21 vs. 37 min, p = 0.001) were higher in PLS group. DFS at 1, 3, 5, and 7 years in HALS/Hybrid and PLS groups were 65.4%, 39.3%, 37.5%, and 36.3% vs. 64.9%, 38.0%, 33.1%, and 33.1%, respectively (p = 0.84). OS at 1, 3, 5, and 7 years in HALS/Hybrid and PLS groups were 94.5%, 71.4%, 54.3%, and 46.0% vs. 96.0%, 68.5%, 51.2%, and 41.2%, respectively (p = 0.73).

CONCLUSION

Our study suggests no differences in long-term oncologic outcomes between the two techniques. We discovered that longer total operative, pringle time, higher rates of intraoperative ablation, and positive resection margins were associated with PLS. These differences in favor of HALS/Hybrid could be due to a shorter learning curve and a greater ability to control hemorrhage.

An International Expert Delphi Consensus on Defining Textbook Outcome in Liver Surgery (TOLS)

OBJECTIVE

To reach global expert consensus on the definition of TOLS in minimally invasive and open liver resection among renowned international expert liver surgeons using a modified Delphi method.

BACKGROUND

Textbook outcome is a novel composite measure combining the most desirable postoperative outcomes into one single measure and representing the ideal postoperative course. Despite a recently developed international definition of Textbook Outcome in Liver Surgery (TOLS), a standardized and expert consensus-based definition is lacking.

METHODS

This international, consensus-based, qualitative study used a Delphi process to achieve consensus on the definition of TOLS. The survey comprised 6 surgical domains with a total of 26 questions on individual surgical outcome variables. The process included 4 rounds of online questionnaires. Consensus was achieved when a threshold of at least 80% agreement was reached. The results from the Delphi rounds were used to establish an international definition of TOLS.

RESULTS

In total, 44 expert liver surgeons from 22 countries and all 3 major international hepato-pancreato-biliary associations completed round 1. Forty-two (96%), 41 (98%), and 41 (98%) of the experts participated in round 2, 3, and 4, respectively. The TOLS definition derived from the consensus process included the absence of intraoperative grade ≥2 incidents, postoperative bile leakage grade B/C, postoperative liver failure grade B/C, 90-day major postoperative complications, 90-day readmission due to surgery-related major complications, 90-day/in-hospital mortality, and the presence of R0 resection margin.

CONCLUSIONS

This is the first study providing an international expert consensus-based definition of TOLS for minimally invasive and open liver resections by the use of a formal Delphi consensus approach. TOLS may be useful in assessing patient-level hospital performance and carrying out international comparisons between centers with different clinical practices to further improve patient outcomes.

Learning deep abdominal CT registration through adaptive loss weighting and synthetic data generation

PURPOSE

This study aims to explore training strategies to improve convolutional neural network-based image-to-image deformable registration for abdominal imaging.

METHODS

Different training strategies, loss functions, and transfer learning schemes were considered. Furthermore, an augmentation layer which generates artificial training image pairs on-the-fly was proposed, in addition to a loss layer that enables dynamic loss weighting.

RESULTS

Guiding registration using segmentations in the training step proved beneficial for deep-learning-based image registration. Finetuning the pretrained model from the brain MRI dataset to the abdominal CT dataset further improved performance on the latter application, removing the need for a large dataset to yield satisfactory performance. Dynamic loss weighting also marginally improved performance, all without impacting inference runtime.

CONCLUSION

Using simple concepts, we improved the performance of a commonly used deep image registration architecture, VoxelMorph. In future work, our framework, DDMR, should be validated on different datasets to further assess its value.

A Comparison between Open and Minimally Invasive Techniques for the Resection of Colorectal Liver Metastasis

The liver is the most common site of colorectal cancer metastasis. Liver surgery is a cornerstone in treatment, with progressive expansion of minimally invasive surgery (MIS). This study aims to compare short- and long-term outcomes of open surgery and MIS for the treatment of colorectal adenocarcinoma liver metastasis during the first three years of increasing caseload and implementation of MIS use in liver surgery. All patients treated between November 2018 and August 2021 at Careggi Teaching Hospital in Florence, Italy, were prospectively entered into a database and retrospectively reviewed. Fifty-one patients were resected (41 open, 10 MIS). Considering that patients with a significantly higher number of lesions underwent open surgery and operative results were similar, postoperative morbidity rate and length of hospital stay were significantly higher in the open group. No differences were found in the pathological specimen. The postoperative mortality rate was 2%. Mean overall survival and disease-free survival were 46 months (95% CI 42-50) and 22 months (95% CI 15.6-29), respectively. The use of minimally invasive techniques in liver surgery is safe and feasible if surgeons have adequate expertise. MIS and parenchymal sparing resections should be preferred whenever technically feasible.

The prognostic significance of a histological response to preoperative chemotherapy in patients with synchronous colorectal liver metastases

Objective: Preoperative chemotherapy (PC) for colorectal liver metastasis (CRLM) is widely used to improve prognosis, but its clinical benefit has not been fully established. This study aimed to assess the effectiveness of PC for synchronous CRLM and the correlation between the histological response to PC and survival. Summary of Background Data: We enrolled 69 patients who underwent initial hepatectomy for synchronous CRLM between 2004 and 2018 at Gifu University Hospital. Methods: We retrospectively analyzed the clinicopathological factors and outcomes of 69 patients who underwent hepatectomy after receiving PC (PC group: n = 43) or who underwent upfront hepatectomy (non-PC group: n = 26). In the PC group, the patients were divided into the Grade 1 (n = 27) and Grade 2/3 (n = 16) groups according to their histological responses to PC. Results: The median survival and 5-year overall survival (OS) rates were 80.9 months and 61.5%, respectively, in the PC group and 71.7 months and 61.5%, respectively, in the non-PC group ( P = 0.867). Regarding recurrence-free survival (RFS) and remnant liver-RFS, there were no significant differences between the two groups ( P = 0.087 and 0.291). However, in a subgroup analysis, the median 5-year OS, RFS, and remnant liver RFS were significantly longer in the Grade 2/3 than Grade 1 group ( P = 0.008, P = 0.002, and P &lt; 0.001, respectively). Conclusions: Some patients benefit from PC, and the histological response to PC had prognostic significance for patients with synchronous CRLM.

Open versus laparoscopic liver resection of colorectal metastases: a meta-analysis of matched patient populations

In recent years, the management of colorectal liver metastases (CRLM) has evolved significantly. Laparoscopic liver resection is increasingly being performed, despite a lack of major randomized controlled trial evidence or widespread international consensus. The objective of this review was to compare the short- and long-term outcomes following open and laparoscopic CRLM resection. A systematic review of comparative matched population studies was performed. Evaluated endpoints included surgical outcomes and survival outcomes. Twelve studies were included in this review, reporting on 3095 patients. R0 (negative margins) rates were higher in the laparoscopic CRLM group (89.3% versus 86.9%). In addition, laparoscopic resection was associated with less blood loss (486 mls versus 648 mls, p ≤ 0.0001*) and reduced blood transfusion rates (6.7% vs. 12.2%, OR 2.13, 95% CI 1.08-4.19, p = 0.03*). Major complication rates were higher in the open CRLM group (12.5% vs. 8.1%, OR 1.74, 95% CI 1.30-2.33, p = 0.03*), as was overall hospital length of stay (median 7 versus 5.5 days, p = 0.001*). Perioperative mortality was similar between both groups, and there was no significance in 5-year overall survival for open or laparoscopic CRLM resection groups (58% and 61% respectively). Laparoscopic CRLM resection is associated with less blood loss, lower transfusion rates, major complications, and overall hospital length of stay with comparable oncological outcome.

Prospective Non-Randomized Study of Intraoperative Assessment of Surgical Resection Margin of Colo-Rectal Liver Metastases

Introduction: More than 50% of patients with colorectal cancer (CRC) develop liver metastases during the natural course of disease. Surgical resection is currently the most potentially curative method in the treatment of colorectal liver metastases (CRLM). The goal of surgery is to achieve a negative resection margin (RM) of at least 1 mm, which provides the best prognosis for patients. The RM can be assessed by the pathologist of the resected liver specimen (RLS) and by the surgeon intraoperatively. The aim of this research paper is to determine the degree of agreement on intraoperative assessment of the RM by the surgeon and histopathological RM assessment by the pathologist.

Material and methods: This prospective non-randomized double-blind study was approved by the Ethics Committee of the Oncology Institute of Vojvodina and registered on ClinicalTrials.gov #NCT04634526. The study was conducted at the Oncology Institute of Vojvodina, Sremska Kamenica, Serbia. An experienced hepatobiliary surgeon assessed RM for every specimen intra-operatively, immediately after CRLM resection. Resected CRLM lesions were analyzed by two experienced pathologists. These data were compared with pathological RM assessment as a “gold standard”. RM of 1 mm or more was rated as negative RM (RM-). Disease-free survival (DFS) and recurrence rate was calculated by RM status defined by surgeon and by pathologist.

Results: From 01 January 2015 to 31 August 2019, 98 patients were enrolled in the study. There were 219 RLS with 245 CRLM. The surgeon registered positive RM (RM+) of <1mm in 41 (18.7%) RLS. Taking the result of the histopathological assessment (HPA) as the “gold standard”, it was determined that RM was true positive in 32 (14.6%) cases. False positive RM was found in 9 (4.1%) cases. False negative RM was found in 20 (9.1%) cases. True negative RM was found in 158 (72.2%) cases. Sensitivity of surgical assessment (SA) of RM+ was 61.5% (32/52). Specificity of SA of RM+ was 94.6% (158/167). The positive predictive value (PPV) was 78.0% (32/41), while the negative predictive value (NPV) was 88.8% (158/178). The overall accuracy of the RM+ SA was 86.8% (190/219). There was no statistically significant difference in the assessment of RM+ per RLS by surgeon and pathologists (p=0.061), but it was significant when analyses per patients was performed (p=0.017). Recurrence rate for RM+ patients was 48.1% (13/27, p=0.05) for SA and 35.0% (14/40, p=0.17) for HPA. Three year DFS for RM- and RM+ was 66.5% and 27.9% (p=0.04), respectively, by SA, and 64.8% and 42.1% (p=0.106), respectively, by HPA.

Conclusion: Intraoperative assessment of RM- by surgeon of RLS is clinically meaningful. There is not a statistically significant difference in the assessment of RM+ by surgeon and pathologists per RLS, but it was statically significant on a per patient basis. RM determined by surgeon has better prognostic impact on recurrence rate and 1- and 3-year DFS than standard histopathological assessment.

Minimal-Invasive Versus Open Hepatectomy for Colorectal Liver Metastases: Bicentric Analysis of Postoperative Outcomes and Long-Term Survival Using Propensity Score Matching Analysis

Minimal-invasive hepatectomy (MIH) has been increasingly performed for benign and malignant liver lesions with most promising short-term results. However, the oncological role of MIH in the treatment of patients with colorectal liver metastases (CRLM) needs further investigation. Clinicopathological data of patients who underwent liver resection for CRLM between 2012 and 2017 at the Department of Surgery, Charité-Universitätsmedizin Berlin, and the Inselspital Bern were assessed. Postoperative outcomes und long-term survivals of patients following MIH were compared with those after conventional open hepatectomy (OH) after 1:1 propensity score matching. During the study period, 229 and 91 patients underwent liver resection for CRLM at the Charité Berlin and the Inselspital Bern, respectively. Patients who underwent MIH in one of the two centers (n = 69) were compared with a matched cohort of patients who underwent OH. MIH was associated with lower complication rates (23% vs. 44%, p = 0.011), shorter length of intensive care unit stay (ICU, 1 vs. 2 days, p = 0.043), shorter length of hospital stay (7 vs. 11 days, p < 0.0001), and a reduced need for intraoperative transfusions (12% vs. 25%, p = 0.047) compared to OH. R0 status was achieved in 93% and 75% of patients after MIH and OH, respectively (p = 0.005). After a median follow-up of 31 months, MIH resulted in similar five-year overall survival (OS) rate (56% vs. 48%, p = 0.116) in comparison to OH. MIH for CRLM is associated with lower postoperative morbidity, shorter length of ICU and hospital stay, reduced need for transfusions, and comparable oncologic outcomes compared to the established OH. Our findings suggest that MIH should be considered as the preferred method for the treatment of curatively resectable CRLM.