Minimally invasive treatment of colorectal liver metastases: does robotic surgery provide any technical advantages over laparoscopy? A multicenter analysis from the IGoMILS (Italian Group of Minimally Invasive Liver Surgery) registry

A novel low-cost high-fidelity porcine model of liver metastases for simulation training in robotic parenchyma-preserving liver resection

In the era of minimally invasive surgery (MIS), parenchyma-preserving liver resections are gaining prominence with the potential to offer improved perioperative outcomes without compromising oncological safety. The surgeon learning curve remains challenging, and simulation plays a key role in surgical training. Existing simulation models can be limited by suboptimal fidelity and high cost. We describe a novel, reproducible, high-fidelity, low-cost liver metastases model using porcine livers from adult Landrace pigs, with porcine perinephric fat used to simulate subcapsular metastases. This model was then utilised in a training session for surgical trainees performing robotic parenchyma-preserving surgery (PPS) under the guidance of expert robotic surgeons, with feedback being recorded. Trainees rated the model highly on its fidelity to human liver simulation (median score 9), tissue handling (median score 8), and overall usefulness (median score 9). Tissue handling was felt to simulate in vivo liver resection closely, while suggestions for improvement included adding simulated blood flow. This is a novel, low-cost, high-fidelity simulation model of liver metastases with high acceptability to surgical trainees, which could be readily adopted by other training centres.

Learning curve in robotic liver surgery: easily achievable, evolving from laparoscopic background and team-based

BACKGROUND

Limited and heterogeneous literature data necessitate a focused examination of the learning curve in robotic liver resections. This study aims to assess the learning curve of two surgeons from the same team with differing laparoscopic backgrounds.

METHODS

Since February 2021, San Raffaele Hospital in Milan has implemented a robotic liver surgery program, performing 250 resections by three trained console surgeons. Using cumulative sum (CUSUM) analysis, the learning curve was evaluated for a Pioneer Surgeon (PS) with around 1200 laparoscopic cases and a New Generation Surgeon (NGS) with approximately 100 laparoscopic cases. Cases were stratified by complexity (38 low, 74 intermediate, 85 high).

RESULTS

Both PS and NGS demonstrated a learning curve for operative time after 15 low-complexity and 10 intermediate-complexity cases, with high-complexity learning curves apparent after 10 cases for PS and 18 cases for NGS. Conversion rates remained unaffected, and neither surgeon experienced increased blood loss or postoperative complications. A "team learning curve" effect in terms of operative time emerged after 12 cases, suggesting the importance of a cohesive surgical team.

CONCLUSION

The robotic platform facilitated a relatively brief learning curve for low and intermediate complexity cases, irrespective of laparoscopic background, underscoring the benefits of team collaboration.

Comparing Open, Laparoscopic and Robotic Liver Resection for Metastatic Colorectal Cancer-A Systematic Review and Network Meta-Analysis

Colorectal liver metastases (CRLM) can be surgically managed through open resections (OLR), laparoscopic resections (LLR), or robotic liver resections (RLR). However, there is ongoing uncertainty regarding the safety and effectiveness of minimally invasive approaches like LLR and RLR. This study aims to clarify these issues by conducting a network meta-analysis (NMA) to compare outcomes across OLR, LLR and RLR for patients with CRLM. Following the PRISMA-NMA guidelines, the meta-analysis included 13 studies with a combined total of 6582 patients. Of these, 50.6% underwent LLR, 45.3% underwent OLR, and 4.1% underwent RLR. The analysis found no significant differences in R0 resection rates between LLR (odds ratio [OR] 1.03, 95% confidence interval [CI]: 0.84-1.26) and RLR (OR 1.57, 95% CI: 0.98-2.51) when compared to OLR. Additionally, there were no significant differences in disease-free survival (DFS) and overall survival (OS) at 1, 3, and 5 years. Despite these findings, both LLR and RLR were associated with reduced postoperative complication rates (RLR: OR 0.52, 95% CI: 0.32-0.86; LLR: OR 0.50, 95% CI: 0.37-0.68). However, patients undergoing LLR were more likely to require conversion to open surgery compared to those undergoing RLR (OR: 12.46, 95% CI: 2.64-58.67). Furthermore, RLR was associated with a reduced need for blood transfusions (OR: 0.13, 95% CI: 0.05-0.32), and LLR resulted in shorter hospital stays (mean difference: -6.66 days, 95% CI: -11.6 to -1.88 days). This study demonstrates the oncological safety of LLR and RLR approaches for CRLM relative to OLR, with enhanced perioperative outcomes anticipated following minimally invasive resections of CRLM.

Challenges and Opportunities for Precision Surgery for Colorectal Liver Metastases

The incidence of colorectal cancer and colorectal liver metastases (CRLM) is increasing globally due to an interaction of environmental and genetic factors. A minority of patients with CRLM have surgically resectable disease, but for those who have resection as part of multimodal therapy for their disease, long-term survival has been shown. Precision surgery-the idea of careful patient selection and targeting of surgical intervention, such that treatments shown to be proven to benefit on a population level are the optimal treatment for each individual patient-is the new paradigm of care. Key to this is the understanding of tumour molecular biology and clinically relevant mutations, such as KRAS, BRAF, and microsatellite instability (MSI), which can predict poorer overall outcomes and a poorer response to systemic therapy. The emergence of immunotherapy and hepatic artery infusion (HAI) pumps show potential to convert previously unresectable disease to resectable disease, in addition to established systemic and locoregional therapies, but the surgeon must be wary of poor-quality livers and the spectre of post-hepatectomy liver failure (PHLF). Volume modulation, a cornerstone of hepatic surgery for a generation, has been given a shot in the arm with the advent of liver venous depletion (LVD) ensuring significantly more hypertrophy of the future liver remnant (FLR). The optimal timing of liver resection for those patients with synchronous disease is yet to be truly established, but evidence would suggest that those patients requiring complex colorectal surgery and major liver resection are best served with a staged approach. In the operating room, parenchyma-preserving minimally invasive surgery (MIS) can dramatically reduce the surgical insult to the patient and lead to better perioperative outcomes, with quicker return to function.

Robotic versus Laparoscopic Liver Resections for Colorectal Metastases: A Systematic Review and Meta-Analysis

Colorectal cancer is the third most common cancer worldwide, and the liver is the most common localization of metastatic disease. The incidence of minimally invasive liver surgery is increasing, and robotic surgery (RLR) is believed to overcome some limitations of a laparoscopic approach (LRL). We performed a systematic review and meta-analysis of operative and short-term oncologic outcomes of the laparoscopic versus robotic-assisted liver resection for colorectal liver metastases. An online search of PubMed, Embase, Scopus, and the Cochrane databases was performed. Eight studies involving 3210 patients were considered eligible for the meta-analysis. In the LRL group, a higher conversion to open rate (12.4%) was observed compared to the RLR (6.7%; p = <0.001). 30-day mortality was 0.7% for the LRL group compared to 0.5% for the RLR group (p = 0.76). Mortality in longer periods among LLR and RLR amounted to 18.2% vs. 8.0% for 1-year mortality (p = 0.07), 34.1% vs. 26.7% for 2-year mortality (p = 0.13), and 52.3% vs. 48.3% for 3-year mortality (p = 0.46). The length of hospital stay was 5.6 ± 2.5 vs. 5.8 ± 2.1 days, respectively (p = 0.47). There were no significant differences between the incidence of individual complications in the LRL and RLR groups (p = 0.78). Laparoscopic or robotic approaches for colorectal liver metastases are comparable in terms of safety and effectiveness. There are significant advantages to robotic surgery, although there is still no long-term evidence concerning overall survival, and the number of patients operated on using RLR remains small.

Contemporary Surgical Management of Colorectal Liver Metastases

Colorectal cancer is the third most common cancer in the United States and the second most common cause of cancer-related death. Approximately 20-30% of patients will develop hepatic metastasis in the form of synchronous or metachronous disease. The treatment of colorectal liver metastasis (CRLM) has evolved into a multidisciplinary approach, with chemotherapy and a variety of locoregional treatments, such as ablation and portal vein embolization, playing a crucial role. However, resection remains a core tenet of management, serving as the gold standard for a curative-intent therapy. As such, the input of a dedicated hepatobiliary surgeon is paramount for appropriate patient selection and choice of surgical approach, as significant advances in the field have made management decisions extremely nuanced and complex. We herein aim to review the contemporary surgical management of colorectal liver metastasis with respect to both perioperative and operative considerations.

Robotic versus open resection for colorectal liver metastases in a "referral centre Hub&Spoke learning program". A multicenter propensity score matching analysis of perioperative outcomes

Background

Surgical resection is still considered the optimal treatment for colorectal liver metastasis (CRLM). Although laparoscopic and robotic surgery demonstrated their reliability especially in referral centers, the comparison between perioperative outcomes of robotic liver resection (RLR) and open (OLR) liver resection are still debated when performed in referral centers for robotic surgery, not dedicated to HPB. Our study aimed to verify the efficacy and safety of perioperative outcomes after RLR and OLR for CRLM in an HUB&Spoke learning program (H&S) between a high volume center for liver surgery and high volume center for robotic surgery.

Methods

We analyzed prospective databases of Pineta Grande Hospital (Castel Volturno) and Robotic Surgical Units (Foligno-Spoleto and Arezzo) from 2011 to 2021. A 1:1 propensity score matching (PSM) was performed according to baseline characteristics of patients, solitary/multiple CRLM, anterolateral/posterosuperior location.

Results

383 patients accepted to be part of the study (268 ORL and 115 RLR). After PSM, 45 patients from each group were included. Conversion rate was 8.89 %. RLR group had a significantly lower blood loss (226 vs. 321 ml; p=0.0001), and fewer major complications (13.33 % vs. 17.78 %; p=0.7722). R0 resection was obtained in 100% of OLR (vs.95.55%, p =0.4944. Hospital stay was 8.8 days in RLR (vs. 15; p=0.0001).Conclusion: H&S represents a safe and effective program to train general surgeons also in Hepatobiliary surgery providing R0 resection rate, blood loss volume and morbidity rate superimposable to referral centers. Furthermore, H&S allow a reduction of health mobility with consequent money saving for patients and institutions.

Colorectal Cancer: Current Updates and Future Perspectives

Colorectal cancer is a frequent neoplasm in western countries, mainly due to dietary and behavioral factors. Its incidence is growing in developing countries for the westernization of foods and lifestyles. An increased incidence rate is observed in patients under 45 years of age. In recent years, the mortality for CRC is decreased, but this trend is slowing. The mortality rate is reducing in those countries where prevention and treatments have been implemented. The survival is increased to over 65%. This trend reflects earlier detection of CRC through routine clinical examinations and screening, more accurate staging through advances in imaging, improvements in surgical techniques, and advances in chemotherapy and radiation. The most important predictor of survival is the stage at diagnosis. The screening programs are able to reduce incidence and mortality rates of CRC. The aim of this paper is to provide a comprehensive overview of incidence, mortality, and survival rate for CRC.

[Robot-assisted visceral surgery in Germany : Analysis of the current status and trends of the last 5 years using data from the StuDoQ|Robotics registry]

Robot-assisted systems have been increasingly used in general surgery for several years. Accordingly, the number of systems installed in Germany has also rapidly increased. While around 100 robot-assisted systems were used in German hospitals in 2018, this figure had already risen to more than 200 by 2022. The aim of this article is to present the current state of development and trends in robotic surgery in Germany. For this purpose, data from the StuDoQ|Robotics register were analyzed. Furthermore, a descriptive analysis of concomitant diagnosis-related groups (DRG) data was carried out via the Federal Statistical Office (Destatis), for a better assessment of the representativeness of the StuDoQ|Robotics register data. In both data sets, the annual number of robot-assisted visceral surgery procedures in Germany steadily increased. Compared to the DRG data, only 3.7% up to a maximum of 36.7% of all robot-assisted procedures performed were documented in the StuDoQ|Robotics register, depending on the type of procedure. Colorectal resections were the most frequent robot-assisted procedures (StuDoQ: 32.5% and 36.7% vs. DRG data: 24.2% and 29.7%) and had, for example, low mortality rates (StuDoQ: 1% and 1% vs. DRG data: 2.3% and 1.3%). Due to the low coverage rates of robot-assisted esophageal, gastric, pancreatic and liver interventions, no valid statements could be derived from the StuDoQ data for these areas. With the current coverage rates, the informative value of the StuDoQ|Robotics register is considerably limited for some types of intervention. In the future, measures should therefore be explored that lead to a significant increase in the coverage rates.

Artificial Intelligence to Early Predict Liver Metastases in Patients with Colorectal Cancer: Current Status and Future Prospectives

BACKGROUND

Artificial Intelligence (AI)-based analysis represents an evolving medical field. In the last few decades, several studies have reported the diagnostic efficiency of AI applied to Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) to early detect liver metastases (LM), mainly from colorectal cancer. Despite the increase in information and the development of different procedures in several radiological fields, an accurate method of predicting LM has not yet been found. This review aims to compare the diagnostic efficiency of different AI methods in the literature according to accuracy, sensibility, precision, and recall to identify early LM.

METHODS

A narrative review of the literature was conducted on PubMed. A total of 336 studies were screened.

RESULTS

We selected 17 studies from 2012 to 2022. In total, 14,475 patients were included, and more than 95% were affected by colorectal cancer. The most frequently used imaging tool to early detect LM was found to be CT (58%), while MRI was used in three cases. Four different AI analyses were used: deep learning, radiomics, machine learning, and fuzzy systems in seven (41.18%), five (29.41%), four (23.53%), and one (5.88%) cases, respectively. Four studies achieved an accuracy of more than 90% after MRI and CT scan acquisition, while just two reported a recall rate ≥90% (one method using MRI and CT and one CT).

CONCLUSIONS

Routinely acquired radiological images could be used for AI-based analysis to early detect LM. Simultaneous use of radiomics and machine learning analysis applied to MRI or CT images should be an effective method considering the better results achieved in the clinical scenario.

Robotic hepatectomy: current evidence and future directions

Minimally invasive hepatectomy continues to gain popularity and acceptance for treatment of benign and malignant liver disease. Robotic hepatectomy offers potential advantages over open and conventional laparoscopic approaches. Review of the literature on robotic hepatectomy was performed. Search terms included "robotic hepatectomy" and "minimally invasive hepatectomy." Search was further customized to include articles related to robotic surgical technology. Across many parameters in liver surgery, robotic liver resection appears to have comparable outcomes with respect to laparoscopic resection. The benefits over open resection are largely related to less morbidity and faster recovery times. There is evidence that the robotic approach may have a shorter learning curve and enable more difficult resections to be performed minimally invasively. The robotic platform may have the potential to achieve superior margin status or parenchymal sparing resection in oncologic resections, but numerous obstacles remain. The robotic platform has not been applied to liver surgery to the same extent as either laparoscopic or open surgery. Robotic surgical technology will need to continue developing to deliver on its potential advantages.

International experts consensus guidelines on robotic liver resection in 2023

The robotic liver resection (RLR) has been increasingly applied in recent years and its benefits shown in some aspects owing to the technical advancement of robotic surgical system, however, controversies still exist. Based on the foundation of the previous consensus statement, this new consensus document aimed to update clinical recommendations and provide guidance to improve the outcomes of RLR clinical practice. The guideline steering group and guideline expert group were formed by 29 international experts of liver surgery and evidence-based medicine (EBM). Relevant literature was reviewed and analyzed by the evidence evaluation group. According to the WHO Handbook for Guideline Development, the Guidance Principles of Development and Amendment of the Guidelines for Clinical Diagnosis and Treatment in China 2022, a total of 14 recommendations were generated. Among them were 8 recommendations formulated by the GRADE method, and the remaining 6 recommendations were formulated based on literature review and experts' opinion due to insufficient EBM results. This international experts consensus guideline offered guidance for the safe and effective clinical practice and the research direction of RLR in future.

Hepatic Resection in Patients with Colo-Rectal Liver Metastases: Surgical Outcomes and Prognostic Factors of Single-Center Experience

INTRODUCTION

Surgical resection has a fundamental role in increasing the chance of survival in patients with colorectal liver metastases. The guidelines have been modified and expanded in time in order to increase the number of patients that can benefit from this treatment. The aim of this study is to analyze the main prognostic factors related to overall and disease-free survival of a series of consecutive patients undergoing liver resection for colorectal liver metastases (CRLM).

MATERIALS AND METHODS

A retrospective review of patients undergoing liver resection for CRLM between April 2018 and September 2021 was performed. Clinical data and laboratory parameters were evaluated using the log-rank test. OS and DFS were estimated using the Kaplan-Meier method.

RESULTS

A retrospective study on 75 patients who underwent liver resection for CRLM was performed. The OS and DFS at 1 and 3 years were 84.3% and 63.8% for OS, 55.6% and 30.7% for DFS, respectively. From the analysis of the data, the most significant results indicate that: patients with a lower CEA value <25 ng/mL had an OS of 93.6% and 80.1% at 1 and 3 years, with an average of 36.7 months (CI 95% 33.1-40.3); moreover, patients with a value equal to or greater than 25 ng/mL had a 1-year survival equal to 57.4%, with an average of 13.8 months (CI 95% 9.4-18.2) (p < 0.001); adjuvant chemotherapy increases by 3 years the overall survival (OS: 68.6% vs. 49.7%) (p = 0.013); localization of the primary tumor affects OS, with a better prognosis for left colon metastases (OS at 42 months: 85.4% vs. 42.2%) (p value = 0.056); patients with stage T1 or T2 cancer have a better 3 years OS (92.9-100% vs. 49.7-56.3%) (p = 0.696), while the N0 stage results in both higher 3 years OS and DFS than the N + stages (OS: 87.5% vs. 68.5% vs. 24.5%); metachronous metastases have a higher 3 years OS than synchronous ones (80% vs. 47.4%) (p = 0.066); parenchymal sparing resections have a better 3 years DFS than anatomical ones (33.7% vs. 0%) (p = 0.067); a patient with a parenchymal R1 resection has a much worse prognosis than an R0 (3 years OS: 0% vs. 68.7%) (p < 0.001).

CONCLUSIONS

CEA value of less than 25 ng/mL, localization of the primary tumor in the left colon, primary tumor in stage T1/2 and N0, metachronous presentation, R0 resection, fewer than four metastases, and use of adjuvant chemotherapy are all parameters that in our analysis have shown a correlation with a better prognosis; moreover, the evaluation of the series is in line with the latest evidence in the literature in defining the non-inferiority of minimally invasive and parenchymal sparing treatment compared to the classic laparotomic approach with anatomic resection.

Recent Advances in Minimally Invasive Liver Resection for Colorectal Cancer Liver Metastases-A Review

Minimally invasive surgical (MIS) approaches to liver resection have been increasingly adopted into use for surgery on colorectal cancer liver metastases. The purpose of this review is to evaluate the outcomes when comparing laparoscopic liver resection (LLR), robotic liver resection (RLR), and open liver resection (OLR) for colorectal cancer liver metastases (CRLM) in 39 studies (2009-2022) that include a case-matched series, propensity score analyses, and three randomized clinical trials. LLR is associated with less intraoperative blood loss and shorter hospital stay compared with OLR. LLR can be performed with comparable operative time. LLR has similar rates of perioperative complications and mortality as OLR. There were no significant differences in 5-year overall or disease-free survival between approaches. Robotic liver resection (RLR) has comparable perioperative safety to LLR and may improve rates of R0 resection in certain patients. Finally, MIS approaches to the hepatic resection of CRLM reduce the time from liver resection to initiation of adjuvant chemotherapy. Thus, MIS liver surgery should be considered in the array of options for patients with CRLM, though thoughtful patient selection and surgeon experience should be part of that decision.

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.

What Is the Current Role and What Are the Prospects of the Robotic Approach in Liver Surgery?

In parallel with the historical development of minimally invasive surgery, the laparoscopic and robotic approaches are now frequently utilized to perform major abdominal surgical procedures. Nevertheless, the role of the robotic approach in liver surgery is still controversial, and a standardized, safe technique has not been defined yet. This review aims to summarize the currently available evidence and prospects of robotic liver surgery. Minimally invasive liver surgery has been extensively associated with benefits, in terms of less blood loss, and lower complication rates, including liver-specific complications such as clinically relevant bile leakage and post hepatectomy liver failure, when compared to open liver surgery. Furthermore, comparable R0 resection rates to open liver surgery have been reported, thus, demonstrating the safety and oncological efficiency of the minimally invasive approach. However, whether robotic liver surgery has merits over laparoscopic liver surgery is still a matter of debate. In the current literature, robotic liver surgery has mainly been associated with non-inferior outcomes compared to laparoscopy, although it is suggested that the robotic approach has a shorter learning curve, lower conversion rates, and less intraoperative blood loss. Robotic surgical systems offer a more realistic image with integrated 3D systems. In addition, the improved dexterity offered by robotic surgical systems can lead to improved intra and postoperative outcomes. In the future, integrated and improved haptic feedback mechanisms, artificial intelligence, and the introduction of more liver-specific dissectors will likely be implemented, further enhancing the robots' abilities.

Current status of robotic surgery for hepato-pancreato-biliary malignancies

INTRODUCTION

Robotic surgery is an emerging aspect of gastrointestinal surgery. Hepato-pancreato-biliary surgery is currently being explored for a broad spectrum of indications, entities, and postoperative outcomes. Noninferiority and financial aspects are the focus of studies. In this review, the impact on oncological therapies is assessed.

AREAS COVERED

An extensive literature review was conducted, and relevant studies and articles and reviews for robotic surgery in the field of hepato-pancreato-biliary surgery were examined. Special attention was given to the oncological aspects of robotic surgery and its possible impact on the therapy of malignant neoplasms.

EXPERT OPINION

Robotic-assisted surgery for oncological indications is promising, in part, an established technique that has already shown its advantages in the last decade, although high-quality studies are missing. Upcoming experience must consider the oncological benefit and putative new indications in a rapidly changing field of anti-neoplastic regimens. Also, robotic surgery may possess the ability to accelerate digitalization and AI-based augmentation in this context.