Can I trust my fake data - A comprehensive quality assessment framework for synthetic tabular data in healthcare

BACKGROUND

Ensuring safe adoption of AI tools in healthcare hinges on access to sufficient data for training, testing and validation. Synthetic data has been suggested in response to privacy concerns and regulatory requirements and can be created by training a generator on real data to produce a dataset with similar statistical properties. Competing metrics with differing taxonomies for quality evaluation have been proposed, resulting in a complex landscape. Optimising quality entails balancing considerations that make the data fit for use, yet relevant dimensions are left out of existing frameworks.

METHOD

We performed a comprehensive literature review on the use of quality evaluation metrics on synthetic data within the scope of synthetic tabular healthcare data using deep generative methods. Based on this and the collective team experiences, we developed a conceptual framework for quality assurance. The applicability was benchmarked against a practical case from the Dutch National Cancer Registry.

CONCLUSION

We present a conceptual framework for quality assuranceof synthetic data for AI applications in healthcare that aligns diverging taxonomies, expands on common quality dimensions to include the dimensions of Fairness and Carbon footprint, and proposes stages necessary to support real-life applications. Building trust in synthetic data by increasing transparency and reducing the safety risk will accelerate the development and uptake of trustworthy AI tools for the benefit of patients.

DISCUSSION

Despite the growing emphasis on algorithmic fairness and carbon footprint, these metrics were scarce in the literature review. The overwhelming focus was on statistical similarity using distance metrics while sequential logic detection was scarce. A consensus-backed framework that includes all relevant quality dimensions can provide assurance for safe and responsible real-life applications of synthetic data. As the choice of appropriate metrics are highly context dependent, further research is needed on validation studies to guide metric choices and support the development of technical standards.

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.

Impact of neoadjuvant chemotherapy on short-term outcomes after simple and complex minimally invasive minor hepatectomy for colorectal liver metastases: A propensity-score matched and coarsened exact matched study

BACKGROUND

In the last three decades, minimally invasive liver resection has been replacing conventional open approach in liver surgery. More recently, developments in neoadjuvant chemotherapy have led to increased multidisciplinary management of colorectal liver metastases with both medical and surgical treatment modalities. However, the impact of neoadjuvant chemotherapy on the surgical outcomes of minimally invasive liver resections remains poorly understood.

METHODS

A multicenter, international, database of 4998 minimally invasive minor hepatectomy for colorectal liver metastases was used to compare surgical outcomes in patients who received neoadjuvant chemotherapy with surgery alone. To correct for baseline imbalance, propensity score matching, coarsened exact matching and inverse probability treatment weighting were performed.

RESULTS

2546 patients met the inclusion criteria. After propensity score matching there were 759 patients in both groups and 383 patients in both groups after coarsened exact matching. Baseline characteristics were equal after both matching strategies. Neoadjuvant chemotherapy was not associated with statistically significant worse surgical outcomes of minimally invasive minor hepatectomy.

CONCLUSION

Neoadjuvant chemotherapy had no statistically significant impact on short-term surgical outcomes after simple and complex minimally invasive minor hepatectomy for colorectal liver metastases.

Minimally invasive robot-assisted and laparoscopic distal pancreatectomy in a pan-European registry a retrospective cohort study

BACKGROUND

International guidelines recommend monitoring of the use and outcome of minimally invasive pancreatic surgery (MIPS). However, data from prospective international audits on minimally invasive distal pancreatectomy (MIDP) are lacking. This study examined the use and outcome of robot-assisted (RDP) and laparoscopic (LDP) distal pancreatectomy in the E-MIPS registry.

MATERIALS AND METHODS

Post-hoc analysis in a prospective audit on MIPS, including consecutive patients undergoing MIDP in 83 centers from 19 European countries (01-01-2019/31-12-2021). Primary outcomes included intraoperative events (grade 1: excessive blood loss, grade 2: conversion/change in operation, grade 3: intraoperative death), major morbidity, and in-hospital/30-day mortality. Multivariable logistic regression analyses identified high-risk groups for intraoperative events. RDP and LDP were compared in the total cohort and in high-risk groups.

RESULTS

Overall, 1672 patients undergoing MIDP were included; 606 (36.2%) RDP and 1066 (63.8%) LDP. The annual use of RDP increased from 30.5% to 42.6% (P<0.001). RDP was associated with fewer grade 2 intraoperative events compared to LDP (9.6% vs. 16.8%, P<0.001), with longer operating time (238 vs. 201 minutes,P<0.001). No significant differences were observed between RDP and LDP regarding major morbidity (23.4% vs. 25.9%, P=0.264) and in-hospital/30-day mortality (0.3% vs. 0.8%, P=0.344). Three high-risk groups were identified; BMI>25 kg/m2, previous abdominal surgery, and vascular involvement. In each group, RDP was associated with fewer conversions and longer operative times.

CONCLUSION

This European registry-based study demonstrated favorable outcomes for MIDP, with mortality rates below 1%. LDP remains the predominant approach, whereas the use of RDP is increasing. RDP was associated with less conversions and longer operative time, including in high-risk subgroups. Future randomized trials should confirm these findings and assess cost differences.

Hybrid optical-vision tracking in laparoscopy: accuracy of navigation and ultrasound reconstruction

INTRODUCTION

The use of laparoscopic and robotic liver surgery is increasing. However, it presents challenges such as limited field of view and organ deformations. Surgeons rely on laparoscopic ultrasound (LUS) for guidance, but mentally correlating ultrasound images with pre-operative volumes can be difficult. In this direction, surgical navigation systems are being developed to assist with intra-operative understanding. One approach is performing intra-operative ultrasound 3D reconstructions. The accuracy of these reconstructions depends on tracking the LUS probe.

MATERIAL AND METHODS

This study evaluates the accuracy of LUS probe tracking and ultrasound 3D reconstruction using a hybrid tracking approach. The LUS probe is tracked from laparoscope images, while an optical tracker tracks the laparoscope. The accuracy of hybrid tracking is compared to full optical tracking using a dual-modality tool. Ultrasound 3D reconstruction accuracy is assessed on an abdominal phantom with CT transformed into the optical tracker's coordinate system.

RESULTS

Hybrid tracking achieves a tracking error < 2 mm within 10 cm between the laparoscope and the LUS probe. The ultrasound reconstruction accuracy is approximately 2 mm.

CONCLUSION

Hybrid tracking shows promising results that can meet the required navigation accuracy for laparoscopic liver surgery.

Postoperative Hyperamylasemia (POH) is an Early Predictor of Pancreatic Fistula Occurrence and Severity after Distal Pancreatectomy: Results from a European Multicentric Study

OBJECTIVES

The aim of this international multicentric study is to characterize postoperative hyperamylasemia (POH) after distal pancreatectomy (DP), with particular focus on its relationship with postoperative pancreatic fistula (POPF) occurrence and severity.

BACKGROUND

The clinical relevance of POH after DP and its relationship with the occurrence and severity of POPF have not been explored yet.

METHODS

All patients undergoing DP for any indication between 2015 and 2021 at three European referral Centers for pancreatic surgery were retrospectively analyzed. Drain fluid amylase (DFA), C-reactive protein (C-RP), and serum amylase were examined from postoperative-day (POD) 1 to 3. Biochemical leak (BL), POPF, POH, and post-pancreatectomy hemorrhage (PPH) were defined and graded according to ISGPS definitions.

RESULTS

In total 1192 patients were included. Overall rates of POH and POPF were 18% (n= 210) and 29% (n= 344), respectively. The presence of DFA ≥2000 U/L on POD 1 (OR=2.11, 95% CI 1.68-2.86), C-RP ≥200 mg/L on POD 3 (OR=2.19, 95% CI 1.68-2.86), and POH (OR=1.58, 95% CI 1.14-2.19) were all independent early predictors of POPF (all P< 0.01). The presence of POH almost doubled the rate of POPF (43% vs. 26%, P<0.001), and higher POPF severity presented also higher POH rates (no POPF= 12%; BL= 19%; B POPF= 24%; C POPF= 52%). Among patients developing POPF, patients with POH had higher rates of PPH (22% vs 9%, P= 0.001), sepsis (24% vs 13%; P=0.011), re-operation (21% vs 8%; P< 0.01), and mortality (3% vs 0.3%; P= 0.025).

CONCLUSIONS

The occurrence of POH is an early predictor of POPF and its severity after DP. The diagnosis of POH might define patients at higher risk for a complicated course, targeting them for prevention / mitigation strategies against pancreas specific complications.

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.

Trends in the characteristics and perioperative outcomes of patients undergoing laparoscopic and open resections for benign liver lesions: An international multicenter retrospective cohort study of 845 patients

BACKGROUND

Solid benign liver lesions (BLL) are increasingly discovered, but clear indications for surgical treatment are often lacking. Concomitantly, laparoscopic liver surgery is increasingly performed. The aim of this study was to assess if the availability of laparoscopic surgery has had an impact on the characteristics and perioperative outcomes of patients with BLL.

METHODS

This is a retrospective international multicenter cohort study, including patients undergoing a laparoscopic or open liver resection for BLL from 19 centers in eight countries. Patients were divided according to the time period in which they underwent surgery (2008-2013, 2014-2016, and 2017-2019). Unadjusted and risk-adjusted (using logistic regression) time-trend analyses were performed. The primary outcome was textbook outcome (TOLS), defined as the absence of intraoperative incidents ≥ grade 2, bile leak ≥ grade B, severe complications, readmission and 90-day or in-hospital mortality, with the absence of a prolonged length of stay added to define TOLS+.

RESULTS

In the complete dataset comprised of patients that underwent liver surgery for all indications, the proportion of patients undergoing liver surgery for benign disease remained stable (12.6% in the first time period, 11.9% in the second time period and 12.1% in the last time period, p = 0.454). Overall, 845 patients undergoing a liver resection for BLL in the first (n = 374), second (n = 258) or third time period (n = 213) were included. The rates of ASA-scores≥3 (9.9%-16%,p < 0.001), laparoscopic surgery (57.8%-77%,p < 0.001), and Pringle maneuver use (33.2%-47.2%,p = 0.001) increased, whereas the length of stay decreased (5 to 4 days,p < 0.001). There were no significant changes in the TOLS rate (86.6%-81.3%,p = 0.151), while the TOLS + rate increased from 41.7% to 58.7% (p < 0.001). The latter result was confirmed in the risk-adjusted analyses (aOR 1.849,p = 0.004).

CONCLUSION

The surgical treatment of BLL has evolved with an increased implementation of the laparoscopic approach and a decreased length of stay. This evolution was paralleled by stable TOLS rates above 80% and an increase in the TOLS + rate.

Implementation and outcome of minimally invasive pancreatoduodenectomy in Europe: a registry-based retrospective study A critical appraisal of the first 3 years of the E-MIPS registry

BACKGROUND

International multicenter audit-based studies focusing on the outcome of minimally invasive pancreatoduodenectomy (MIPD) are lacking. The European registry for Minimally Invasive Pancreatic Surgery (E-MIPS) is the E-AHPBA endorsed registry aimed to monitor and safeguard the introduction of MIPD in Europe.

MATERIALS AND METHODS

A planned analysis of outcomes among consecutive patients after MIPD from 45 centers in 14 European countries in the E-MIPS registry (2019-2021). Main outcomes of interest were major morbidity (Clavien-Dindo grade ≥3) and 30-day/in-hospital mortality.

RESULTS

Overall, 1,336 patients after MIPD were included (835 robot-assisted (R-MIPD) and 501 laparoscopic MIPD (L-MIPD)). Overall, 20 centers performed R-MIPD, 15 centers L-MIPD, and 10 centers both. Between 2019 and 2021, the rate of centers performing L-MIPD decreased from 46.9% to 25%, whereas for R-MIPD this increased from 46.9% to 65.6%. Overall, the rate of major morbidity was 41.2%, 30-day/in-hospital mortality 4.5%, conversion rate 9.7%, POPF grade B/C 22.7%, and PPH grade B/C 10.8%. Median length of hospital stay was 12 days [IQR 8-21]. A lower rate of major morbidity, POPF grade B/C, PPH grade BH/C, DGE grade B/C, percutaneous drainage and readmission was found after L-MIPD. The number of centers meeting the Miami Guidelines volume cut-off of ≥20 MIPDs annually increased from 9 (28.1%) in 2019 to 12 (37.5%) in 2021 (P=0.424). Rates of conversion (7.4% vs. 14.8% P<0.001) and reoperation (8.9% vs. 15.1%) P<0.001) were lower in centers which fulfilled the Miami volume cut-off.

CONCLUSION

During the first 3 years of the pan-European E-MIPS registry, morbidity and mortality rates after MIPD were acceptable. A shift is ongoing from L-MIPD to R-MIPD. Variations in outcomes between the two minimally invasive approaches and the impact of the volume-cut-off should be further evaluated over a longer time period.

Impact of Liver Cirrhosis, Severity of Cirrhosis, and Portal Hypertension on the Difficulty and Outcomes of Laparoscopic and Robotic Major Liver Resections for Primary Liver Malignancies

BACKGROUND

Minimally invasive liver resections (MILR) offer potential benefits such as reduced blood loss and morbidity compared with open liver resections. Several studies have suggested that the impact of cirrhosis differs according to the extent and complexity of resection. Our aim was to investigate the impact of cirrhosis on the difficulty and outcomes of MILR, focusing on major hepatectomies.

METHODS

A total of 2534 patients undergoing minimally invasive major hepatectomies (MIMH) for primary malignancies across 58 centers worldwide were retrospectively reviewed. Propensity score (PSM) and coarsened exact matching (CEM) were used to compare patients with and without cirrhosis.

RESULTS

A total of 1353 patients (53%) had no cirrhosis, 1065 (42%) had Child-Pugh A and 116 (4%) had Child-Pugh B cirrhosis. Matched comparison between non-cirrhotics vs Child-Pugh A cirrhosis demonstrated comparable blood loss. However, after PSM, postoperative morbidity and length of hospitalization was significantly greater in Child-Pugh A cirrhosis, but these were not statistically significant with CEM. Comparison between Child-Pugh A and Child-Pugh B cirrhosis demonstrated the latter had significantly higher transfusion rates and longer hospitalization after PSM, but not after CEM. Comparison of patients with cirrhosis of all grades with and without portal hypertension demonstrated no significant difference in all major perioperative outcomes after PSM and CEM.

CONCLUSIONS

The presence and severity of cirrhosis affected the difficulty and impacted the outcomes of MIMH, resulting in higher blood transfusion rates, increased postoperative morbidity, and longer hospitalization in patients with more advanced cirrhosis. As such, future difficulty scoring systems for MIMH should incorporate liver cirrhosis and its severity as variables.

The Brescia Internationally Validated European Guidelines on Minimally Invasive Pancreatic Surgery (EGUMIPS)

OBJECTIVE

To develop and update evidence-based and consensus-based guidelines on laparoscopic and robotic pancreatic surgery.

SUMMARY BACKGROUND DATA

Minimally invasive pancreatic surgery (MIPS), including laparoscopic and robotic surgery, is complex and technically demanding. Minimizing the risk for patients requires stringent, evidence-based guidelines. Since the International Miami Guidelines on MIPS in 2019, new developments and key publications have been reported, necessitating an update.

METHODS

Evidence-based guidelines on 22 topics in 8 domains were proposed: terminology, indications, patients, procedures, surgical techniques and instrumentation, assessment tools, implementation and training, and artificial intelligence. The Brescia Internationally Validated European Guidelines on Minimally Invasive Pancreatic Surgery (EGUMIPS, September 2022) used the Scottish Intercollegiate Guidelines Network (SIGN) methodology to assess the evidence and develop guideline recommendations, the Delphi method to establish consensus on the recommendations among the Expert Committee, and the AGREE II-GRS tool for guideline quality assessment and external validation by a Validation Committee.

RESULTS

Overall, 27 European experts, 6 international experts, 22 international Validation Committee members, 11 Jury Committee members, 18 Research Committee members, and 121 registered attendees of the 2-day meeting were involved in the development and validation of the guidelines. In total, 98 recommendations were developed, including 33 on laparoscopic, 34 on robotic, and 31 on general MIPS, covering 22 topics in 8 domains. Out of 98 recommendations, 97 reached at least 80% consensus among the experts and congress attendees, and all recommendations were externally validated by the Validation Committee.

CONCLUSIONS

The EGUMIPS evidence-based guidelines on laparoscopic and robotic MIPS can be applied in current clinical practice to provide guidance to patients, surgeons, policy-makers, and medical societies.

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.

Impact of liver cirrhosis, severity of cirrhosis and portal hypertension on the difficulty of laparoscopic and robotic minor liver resections for primary liver malignancies in the anterolateral segments

INTRODUCTION

We performed this study in order to investigate the impact of liver cirrhosis (LC) on the difficulty of minimally invasive liver resection (MILR), focusing on minor resections in anterolateral (AL) segments for primary liver malignancies.

METHODS

This was an international multicenter retrospective study of 3675 patients who underwent MILR across 60 centers from 2004 to 2021.

RESULTS

1312 (35.7%) patients had no cirrhosis, 2118 (57.9%) had Child A cirrhosis and 245 (6.7%) had Child B cirrhosis. After propensity score matching (PSM), patients in Child A cirrhosis group had higher rates of open conversion (p = 0.024), blood loss >500 mls (p = 0.001), blood transfusion (p < 0.001), postoperative morbidity (p = 0.004), and in-hospital mortality (p = 0.041). After coarsened exact matching (CEM), Child A cirrhotic patients had higher open conversion rate (p = 0.05), greater median blood loss (p = 0.014) and increased postoperative morbidity (p = 0.001). Compared to Child A cirrhosis, Child B cirrhosis group had longer postoperative stay (p = 0.001) and greater major morbidity (p = 0.012) after PSM, and higher blood transfusion rates (p = 0.002), longer postoperative stay (p < 0.001), and greater major morbidity (p = 0.006) after CEM. After PSM, patients with portal hypertension experienced higher rates of blood loss >500 mls (p = 0.003) and intraoperative blood transfusion (p = 0.025).

CONCLUSION

The presence and severity of LC affect and compound the difficulty of MILR for minor resections in the AL segments. These factors should be considered for inclusion into future difficulty scoring systems for MILR.

International survey on opinions and use of robot-assisted and laparoscopic minimally invasive pancreatic surgery: 5-year follow up

BACKGROUND

Evidence on the value of minimally invasive pancreatic surgery (MIPS) has been increasing but it is unclear how this has influenced the view of pancreatic surgeons on MIPS.

METHODS

An anonymous survey was sent to members of eight international Hepato-Pancreato-Biliary Associations. Outcomes were compared with the 2016 international survey.

RESULTS

Overall, 315 surgeons from 47 countries participated. The median volume of pancreatic resections per center was 70 (IQR 40-120). Most surgeons considered minimally invasive distal pancreatectomy (MIDP) superior to open (ODP) (94.6%) and open pancreatoduodenectomy (OPD) superior to minimally invasive (MIPD) (67.9%). Since 2016, there has been an increase in the number of surgeons performing both MIDP (79%-85.7%, p = 0.024) and MIPD (29%-45.7%, p < 0.001), and an increase in the use of the robot-assisted approach for both MIDP (16%-45.6%, p < 0.001) and MIPD (23%-47.9%, p < 0.001). The use of laparoscopy remained stable for MIDP (91% vs. 88.1%, p = 0.245) and decreased for MIPD (51%-36.8%, p = 0.024).

CONCLUSION

This survey showed considerable changes of MIPS since 2016 with most surgeons considering MIDP superior to ODP and an increased use of robot-assisted MIPS. Surgeons prefer OPD and therefore the value of MIPD remains to be determined in randomized trials.

Propensity-score Matched and Coarsened-exact Matched Analysis Comparing Robotic and Laparoscopic Major Hepatectomies: An International Multicenter Study of 4822 Cases

OBJECTIVE

To compare the outcomes between robotic major hepatectomy (R-MH) and laparoscopic major hepatectomy (L-MH).

BACKGROUND

Robotic techniques may overcome the limitations of laparoscopic liver resection. However, it is unknown whether R-MH is superior to L-MH.

METHODS

This is a post hoc analysis of a multicenter database of patients undergoing R-MH or L-MH at 59 international centers from 2008 to 2021. Data on patient demographics, center experience volume, perioperative outcomes, and tumor characteristics were collected and analyzed. Both 1:1 propensity-score matched (PSM) and coarsened-exact matched (CEM) analyses were performed to minimize selection bias between both groups.

RESULTS

A total of 4822 cases met the study criteria, of which 892 underwent R-MH and 3930 underwent L-MH. Both 1:1 PSM (841 R-MH vs. 841 L-MH) and CEM (237 R-MH vs. 356 L-MH) were performed. R-MH was associated with significantly less blood loss {PSM:200.0 [interquartile range (IQR):100.0, 450.0] vs 300.0 (IQR:150.0, 500.0) mL; P = 0.012; CEM:170.0 (IQR: 90.0, 400.0) vs 200.0 (IQR:100.0, 400.0) mL; P = 0.006}, lower rates of Pringle maneuver application (PSM: 47.1% vs 63.0%; P < 0.001; CEM: 54.0% vs 65.0%; P = 0.007) and open conversion (PSM: 5.1% vs 11.9%; P < 0.001; CEM: 5.5% vs 10.4%, P = 0.04) compared with L-MH. On subset analysis of 1273 patients with cirrhosis, R-MH was associated with a lower postoperative morbidity rate (PSM: 19.5% vs 29.9%; P = 0.02; CEM 10.4% vs 25.5%; P = 0.02) and shorter postoperative stay [PSM: 6.9 (IQR: 5.0, 9.0) days vs 8.0 (IQR: 6.0 11.3) days; P < 0.001; CEM 7.0 (IQR: 5.0, 9.0) days vs 7.0 (IQR: 6.0, 10.0) days; P = 0.047].

CONCLUSIONS

This international multicenter study demonstrated that R-MH was comparable to L-MH in safety and was associated with reduced blood loss, lower rates of Pringle maneuver application, and conversion to open surgery.

Peri-firing compression in prevention of pancreatic fistula after distal pancreatectomy: A systematic review and a cohort study

BACKGROUND/AIMS

Clinically relevant postoperative pancreatic fistula (CR-POPF) after distal pancreatectomy (DP) occurs in 20%-40% of patients and remains a leading cause of morbidity and increased healthcare cost in this patient group. Recently, several studies suggested decreased risk of CR-POPF with the use of peri-firing compression (PFC) technique. The aim of this report was to conduct a systematic review to get an overview of the current knowledge on the use of PFC in DP. In addition, our experience with PFC was presented.

METHODS

The systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Also, 19 patients undergoing DP with the use of PFC at Oslo University Hospital were studied. The primary endpoint was incidence of CR-POPF.

RESULTS

Seven articles reporting a total of 771 patients were ultimately included in the systematic review. Only two of these were case-control studies examining outcomes in patients with and without PFC, while the rest were case series. These were heterogeneous in terms of staplers used, cartridge selection policy, and PFC technique. Both case-control studies reported significantly reduced CR- POPF incidence with PFC. Eight (21%) of our patients developed CR-POPF after DP with PFC. Only one patient developed CR-POPF among those with pancreatic transection site thickness ⩽1.5 cm.

CONCLUSION

Evidence on potential benefits of PFC in DP is limited in quantity and quality. Our findings suggest that the use of PFC does not lead to reduction in the incidence of CR-POPF. Yet, there might be a benefit from PFC when dealing with a thin pancreas.

Severity Grading Systems for Intraoperative Adverse Events. A Systematic Review of the Literature and Citation Analysis

INTRODUCTION

The accurate assessment and grading of adverse events (AE) is essential to ensure comparisons between surgical procedures and outcomes. The current lack of a standardized severity grading system may limit our understanding of the true morbidity attributed to AEs in surgery. The aim of this study is to review the prevalence in which intraoperative adverse event (iAE) severity grading systems are used in the literature, evaluate the strengths and limitations of these systems, and appraise their applicability in clinical studies.

METHODS

A systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. PubMed, Web of Science, and Scopus were queried to yield all clinical studies reporting the proposal and/or the validation of iAE severity grading systems. Google Scholar, Web of Science, and Scopus were searched separately to identify the articles citing the systems to grade iAEs identified in the first search.

RESULTS

Our search yielded 2957 studies, with 7 studies considered for the qualitative synthesis. Five studies considered only surgical/interventional iAEs, while 2 considered both surgical/interventional and anesthesiologic iAEs. Two included studies validated the iAE severity grading system prospectively. A total of 357 citations were retrieved, with an overall self/nonself-citation ratio of 0.17 (53/304). The majority of citing articles were clinical studies (44.1%). The average number of citations per year was 6.7 citations for each classification/severity system, with only 2.05 citations/year for clinical studies. Of the 158 clinical studies citing the severity grading systems, only 90 (56.9%) used them to grade the iAEs. The appraisal of applicability (mean%/median%) was below the 70% threshold in 3 domains: stakeholder involvement (46/47), clarity of presentation (65/67), and applicability (57/56).

CONCLUSION

Seven severity grading systems for iAEs have been published in the last decade. Despite the importance of collecting and grading the iAEs, these systems are poorly adopted, with only a few studies per year using them. A uniform globally implemented severity grading system is needed to produce comparable data across studies and develop strategies to decrease iAEs, further improving patient safety.

Impact of Tumor Size on the Difficulty of Laparoscopic Major Hepatectomies: An International Multicenter Study

INTRODUCTION

Although tumor size (TS) is known to affect surgical outcomes in laparoscopic liver resection (LLR), its impact on laparoscopic major hepatectomy (L-MH) is not well studied. The objectives of this study were to investigate the impact of TS on the perioperative outcomes of L-MH and to elucidate the optimal TS cutoff for stratifying the difficulty of L-MH.

METHODS

This was a post-hoc analysis of 3008 patients who underwent L-MH at 48 international centers. A total 1396 patients met study criteria and were included. The impact of TS cutoffs was investigated by stratifying TS at each 10-mm interval. The optimal cutoffs were determined taking into consideration the number of endpoints which showed a statistically significant split around the cut-points of interest and the magnitude of relative risk after correction for multiple risk factors.

RESULTS

We identified 2 optimal TS cutoffs, 50 mm and 100 mm, which segregated L-MH into 3 groups. An increasing TS across these 3 groups (≤ 50 mm, 51-100 mm, > 100 mm), was significantly associated with a higher open conversion rate (11.2%, 14.7%, 23.0%, P < 0.001), longer operating time (median, 340 min, 346 min, 365 min, P = 0.025), increased blood loss (median, 300 ml,  ml, 400 ml, P = 0.002) and higher rate of intraoperative blood transfusion (13.1%, 15.9%, 27.6%, P < 0.001). Postoperative outcomes such as overall morbidity, major morbidity, and length of stay were comparable across the three groups.

CONCLUSION

Increasing TS was associated with poorer intraoperative but not postoperative outcomes after L-MH. We determined 2 TS cutoffs (50 mm and 10 mm) which could optimally stratify the surgical difficulty of L-MH.

Impact of liver cirrhosis and portal hypertension on minimally invasive limited liver resection for primary liver malignancies in the posterosuperior segments: An international multicenter study

INTRODUCTION

To assess the impact of cirrhosis and portal hypertension (PHT) on technical difficulty and outcomes of minimally invasive liver resection (MILR) in the posterosuperior segments.

METHODS

This is a post-hoc analysis of patients with primary malignancy who underwent laparoscopic and robotic wedge resection and segmentectomy in the posterosuperior segments between 2004 and 2019 in 60 centers. Surrogates of difficulty (i.e, open conversion rate, operation time, blood loss, blood transfusion, and use of the Pringle maneuver) and outcomes were compared before and after propensity-score matching (PSM) and coarsened exact matching (CEM).

RESULTS

Of the 1954 patients studied, 1290 (66%) had cirrhosis. Among the cirrhotic patients, 310 (24%) had PHT. After PSM, patients with cirrhosis had higher intraoperative blood transfusion (14% vs. 9.3%; p = 0.027) and overall morbidity rates (20% vs. 14.5%; p = 0.023) than those without cirrhosis. After coarsened exact matching (CEM), patients with cirrhosis tended to have higher intraoperative blood transfusion rate (12.1% vs. 6.7%; p = 0.059) and have higher overall morbidity rate (22.8% vs. 12.5%; p = 0.007) than those without cirrhosis. After PSM, Pringle maneuver was more frequently applied in cirrhotic patients with PHT (62.2% vs. 52.4%; p = 0.045) than those without PHT.

CONCLUSION

MILR in the posterosuperior segments in cirrhotic patients is associated with higher intraoperative blood transfusion and postoperative morbidity. This parameter should be utilized in the difficulty assessment of MILR.

Preoperative CA19.9 level predicts lymph node metastasis in resectable adenocarcinoma of the head of the pancreas: A further plea for biological resectability criteria

INTRODUCTION

Lymph-nodal involvement (N+) represents an adverse prognostic factor after pancreatoduodenectomy (PD) for pancreatic adenocarcinoma (PDAC). Preoperative diagnostic and staging modalities lack sensitivity for identifying N+. This study aimed to investigate preoperative CA19.9 in predicting the N+ stage in resectable-PDAC (R-PDAC).

METHODS

Patients included in a multi-institutional retrospective database of PDs performed for R-PDAC from January 2000 to June 2021 were analyzed. A preoperative laboratory value of CA19.9 >37 U/L was used in univariate and multivariate logistic regression analysis to determine a possible association with N+. Additionally, different cut-offs of CA19.9 related to the preoperative clinical T (cT) stage was assessed to evaluate the risk of N+.

RESULTS

A total of 2034 PDs from thirteen centers were included in the study. CA19.9>37 U/L was significantly associated with higher N+ at univariate and multivariate analysis (P<0.001). CA19.9 levels >37 U/L were associated with N+ in 75.9%, 81.3%, and 85.7% of patients, respectively, in cT1, cT2, and cT3 tumors and with higher cut-off values for all cT stages.

CONCLUSION

Lymph nodal involvement is strongly related to preoperative CA19.9 levels. Specially in patients staged as cT3 the CA 19.9 could represent a valid and easy tool to suspect nodal involvement. Due to these findings, R-PDAC patients with elevated CA19.9 values should be considered in a more biologically advanced stage.

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.

Impact of liver cirrhosis, the severity of cirrhosis, and portal hypertension on the outcomes of minimally invasive left lateral sectionectomies for primary liver malignancies

BACKGROUND

The impact of cirrhosis and portal hypertension on perioperative outcomes of minimally invasive left lateral sectionectomies remains unclear. We aimed to compare the perioperative outcomes between patients with preserved and compromised liver function (noncirrhotics versus Child-Pugh A) when undergoing minimally invasive left lateral sectionectomies. In addition, we aimed to determine if the extent of cirrhosis (Child-Pugh A versus B) and the presence of portal hypertension had a significant impact on perioperative outcomes.

METHODS

This was an international multicenter retrospective analysis of 1,526 patients who underwent minimally invasive left lateral sectionectomies for primary liver malignancies at 60 centers worldwide between 2004 and 2021. In the study, 1,370 patients met the inclusion criteria and formed the final study group. Baseline clinicopathological characteristics and perioperative outcomes of these patients were compared. To minimize confounding factors, 1:1 propensity score matching and coarsened exact matching were performed.

RESULTS

The study group comprised 559, 753, and 58 patients who did not have cirrhosis, Child-Pugh A, and Child-Pugh B cirrhosis, respectively. Six-hundred and thirty patients with cirrhosis had portal hypertension, and 170 did not. After propensity score matching and coarsened exact matching, Child-Pugh A patients with cirrhosis undergoing minimally invasive left lateral sectionectomies had longer operative time, higher intraoperative blood loss, higher transfusion rate, and longer hospital stay than patients without cirrhosis. The extent of cirrhosis did not significantly impact perioperative outcomes except for a longer duration of hospital stay.

CONCLUSION

Liver cirrhosis adversely affected the intraoperative technical difficulty and perioperative outcomes of minimally invasive left lateral sectionectomies.

Process model analysis of parenchyma sparing laparoscopic liver surgery to recognize surgical steps and predict impact of new technologies

BACKGROUND

Surgical process model (SPM) analysis is a great means to predict the surgical steps in a procedure as well as to predict the potential impact of new technologies. Especially in complicated and high-volume treatments, such as parenchyma sparing laparoscopic liver resection (LLR), profound process knowledge is essential for enabling improving surgical quality and efficiency.

METHODS

Videos of thirteen parenchyma sparing LLR were analyzed to extract the duration and sequence of surgical steps according to the process model. The videos were categorized into three groups, based on the tumor locations. Next, a detailed discrete events simulation model (DESM) of LLR was built, based on the process model and the process data obtained from the endoscopic videos. Furthermore, the impact of using a navigation platform on the total duration of the LLR was studied with the simulation model by assessing three different scenarios: (i) no navigation platform, (ii) conservative positive effect, and (iii) optimistic positive effect.

RESULTS

The possible variations of sequences of surgical steps in performing parenchyma sparing depending on the tumor locations were established. The statistically most probable chain of surgical steps was predicted, which could be used to improve parenchyma sparing surgeries. In all three categories (i-iii) the treatment phase covered the major part (~ 40%) of the total procedure duration (bottleneck). The simulation results predict that a navigation platform could decrease the total surgery duration by up to 30%.

CONCLUSION

This study showed a DESM based on the analysis of steps during surgical procedures can be used to predict the impact of new technology. SPMs can be used to detect, e.g., the most probable workflow paths which enables predicting next surgical steps, improving surgical training systems, and analyzing surgical performance. Moreover, it provides insight into the points for improvement and bottlenecks in the surgical process.

Preoperative Inflammatory Markers in Liver Resection for Colorectal Liver Metastases: A National Registry-Based Study

BACKGROUND

Preoperative inflammatory markers were shown to be associated with prognosis following surgery for hepato-pancreato-biliary cancer. Yet little evidence exists about their role in patients with colorectal liver metastases (CRLM). This study aimed to examine the association between selected preoperative inflammatory markers and outcomes of liver resection for CRLM.

METHODS

Data from the Norwegian National Registry for Gastrointestinal Surgery (NORGAST) was used to capture all liver resections performed in Norway within the study period (November 2015-April 2021). Preoperative inflammatory markers were Glasgow prognostic score (GPS), modified Glasgow prognostic score (mGPS) and C-reactive protein to albumin ratio (CAR). The impact of these on postoperative outcomes, as well as on survival were studied.

RESULTS

Liver resections for CRLM were performed in 1442 patients. Preoperative GPS ≥ 1 and mGPS ≥ 1 were present in 170 (11.8%) and 147 (10.2%) patients, respectively. Both were associated with severe complications but became non-significant in the multivariable model. GPS, mGPS, CAR were significant predictors for overall survival in the univariable analysis, but only CAR remained such in the multivariable model. When stratified by the type of surgical approach, CAR was a significant predictor for survival after open but not laparoscopic liver resections.

CONCLUSIONS

GPS, mGPS and CAR have no impact on severe complications after liver resection for CRLM. CAR outperforms GPS and mGPS in predicting overall survival in these patients, especially following open resections. The prognostic significance of CAR in CRLM should be tested against other clinical and pathology parameters relevant for prognosis.

The Role of Preoperative Inflammatory Markers in Pancreatectomy: a Norwegian Nationwide Cohort Study

BACKGROUND AND PURPOSE

Preoperative inflammatory markers, such as Glasgow prognostic score, modified Glasgow prognostic score and C-reactive protein to albumin ratio, were shown to be associated with prognosis in patients undergoing pancreatectomy for cancer. However, little is known about their predictive role in a Western population.

METHODS

The Norwegian National Registry for Gastrointestinal Surgery (NORGAST) was used to capture all pancreatectomies performed within the study period (November 2015-April 2021). The association between the preoperative inflammatory markers and postoperative outcomes was studied. Their impact on survival was examined in patients operated for pancreatic ductal adenocarcinoma.

RESULTS

A total of 1554 patients underwent pancreatectomy in this period. Glasgow prognostic score, modified Glasgow prognostic score and C-reactive protein to albumin ratio were associated with severe complications (Accordion grade ≥ III) in the univariable but not in the multivariable analysis. C-reactive protein to albumin ratio, but not Glasgow prognostic score and modified Glasgow prognostic score, was linked to survival following pancreatectomy for ductal adenocarcinoma. In the multivariable model, age, neoadjuvant chemotherapy, ECOG score, C-reactive protein to albumin ratio and total pancreatectomy correlated with survival. Also, preoperative C-reactive protein to albumin ratio was significantly associated with survival after pancreatoduodenectomy.

CONCLUSIONS

Preoperative Glasgow prognostic score, modified Glasgow prognostic score and C-reactive protein to albumin ratio have no role in predicting the complications after pancreatectomy. C-reactive protein to albumin ratio is a significant predictor for survival in ductal adenocarcinoma, yet its clinical relevance should be explored in conjunction with the pathology parameters and adjuvant therapy.

Risk Factors and Outcomes of Open Conversion During Minimally Invasive Major Hepatectomies: An International Multicenter Study on 3880 Procedures Comparing the Laparoscopic and Robotic Approaches

INTRODUCTION

Despite the advances in minimally invasive (MI) liver surgery, most major hepatectomies (MHs) continue to be performed by open surgery. This study aimed to evaluate the risk factors and outcomes of open conversion during MI MH, including the impact of the type of approach (laparoscopic vs. robotic) on the occurrence and outcomes of conversions.

METHODS

Data on 3880 MI conventional and technical (right anterior and posterior sectionectomies) MHs were retrospectively collected. Risk factors and perioperative outcomes of open conversion were analyzed. Multivariate analysis, propensity score matching, and inverse probability treatment weighting analysis were performed to control for confounding factors.

RESULTS

Overall, 3211 laparoscopic MHs (LMHs) and 669 robotic MHs (RMHs) were included, of which 399 (10.28%) had an open conversion. Multivariate analyses demonstrated that male sex, laparoscopic approach, cirrhosis, previous abdominal surgery, concomitant other surgery, American Society of Anesthesiologists (ASA) score 3/4, larger tumor size, conventional MH, and Institut Mutualiste Montsouris classification III procedures were associated with an increased risk of conversion. After matching, patients requiring open conversion had poorer outcomes compared with non-converted cases, as evidenced by the increased operation time, blood transfusion rate, blood loss, hospital stay, postoperative morbidity/major morbidity and 30/90-day mortality. Although RMH showed a decreased risk of conversion compared with LMH, converted RMH showed increased blood loss, blood transfusion rate, postoperative major morbidity and 30/90-day mortality compared with converted LMH.

CONCLUSIONS

Multiple risk factors are associated with conversion. Converted cases, especially those due to intraoperative bleeding, have unfavorable outcomes. Robotic assistance seemed to increase the feasibility of the MI approach, but converted robotic procedures showed inferior outcomes compared with converted laparoscopic procedures.

Impact of body mass index on perioperative outcomes of laparoscopic major hepatectomies

BACKGROUND

Data on the effect of body mass index on laparoscopic liver resections are conflicting. We performed this study to investigate the association between body mass index and postoperative outcomes after laparoscopic major hepatectomies.

METHODS

This is a retrospective review of 4,348 laparoscopic major hepatectomies at 58 centers between 2005 and 2021, of which 3,383 met the study inclusion criteria. Concomitant major operations, vascular resections, and previous liver resections were excluded. Associations between body mass index and perioperative outcomes were analyzed using restricted cubic splines. Modeled effect sizes were visually rendered and summarized.

RESULTS

A total of 1,810 patients (53.5%) had normal weight, whereas 1,057 (31.2%) were overweight and 392 (11.6%) were obese. One hundred and twenty-four patients (3.6%) were underweight. Most perioperative outcomes showed a linear worsening trend with increasing body mass index. There was a statistically significant increase in open conversion rate (16.3%, 10.8%, 9.2%, and 5.6%, P < .001), longer operation time (320 vs 305 vs 300 and 266 minutes, P < .001), increasing blood loss (300 vs 300 vs 295 vs 250 mL, P = .022), and higher postoperative morbidity (33.4% vs 26.3% vs 25.0% vs 25.0%, P = .009) in obese, overweight, normal weight, and underweight patients, respectively (P < .001). However, postoperative major morbidity demonstrated a "U"-shaped association with body mass index, whereby the highest major morbidity rates were observed in underweight and obese patients.

CONCLUSION

Laparoscopic major hepatectomy was associated with poorer outcomes with increasing body mass index for most perioperative outcome measures.

Impact of body mass index on the difficulty and outcomes of laparoscopic left lateral sectionectomy

INTRODUCTION

Currently, the impact of body mass index (BMI) on the outcomes of laparoscopic liver resections (LLR) is poorly defined. This study attempts to evaluate the impact of BMI on the peri-operative outcomes following laparoscopic left lateral sectionectomy (L-LLS).

METHODS

A retrospective analysis of 2183 patients who underwent pure L-LLS at 59 international centers between 2004 and 2021 was performed. Associations between BMI and selected peri-operative outcomes were analyzed using restricted cubic splines.

RESULTS

A BMI of >27kg/m2 was associated with increased in blood loss (Mean difference (MD) 21 mls, 95% CI 5-36), open conversions (Relative risk (RR) 1.13, 95% CI 1.03-1.25), operative time (MD 11 min, 95% CI 6-16), use of Pringles maneuver (RR 1.15, 95% CI 1.06-1.26) and reductions in length of stay (MD -0.2 days, 95% CI -0.3 to -0.1). The magnitude of these differences increased with each unit increase in BMI. However, there was a "U" shaped association between BMI and morbidity with the highest complication rates observed in underweight and obese patients.

CONCLUSION

Increasing BMI resulted in increasing difficulty of L-LLS. Consideration should be given to its incorporation in future difficulty scoring systems in laparoscopic liver resections.

Minimally invasive versus open distal pancreatectomy for resectable pancreatic cancer (DIPLOMA): an international randomised non-inferiority trial

Background

The oncological safety of minimally invasive surgery has been questioned for several abdominal cancers. Concerns also exist regarding the use of minimally invasive distal pancreatectomy (MIDP) in patients with resectable pancreatic cancer as randomised trials are lacking.

Methods

In this international randomised non-inferiority trial, we recruited adults with resectable pancreatic cancer from 35 centres in 12 countries. Patients were randomly assigned to either MIDP (laparoscopic or robotic) or open distal pancreatectomy (ODP). Both patients and pathologists were blinded to the assigned approach. Primary endpoint was radical resection (R0, ≥1 mm free margin) in patients who had ultimately undergone resection. Analyses for the primary endpoint were by modified intention-to-treat, excluding patients with missing data on primary endpoint. The pre-defined non-inferiority margin of -7% was compared with the lower limit of the two-sided 90% confidence interval (CI) of absolute difference in the primary endpoint. This trial is registered with the ISRCTN registry (ISRCTN44897265).

Findings

Between May 8, 2018 and May 7, 2021, 258 patients were randomly assigned to MIDP (131 patients) or ODP (127 patients). Modified intention-to-treat analysis included 114 patients in the MIDP group and 110 patients in the ODP group. An R0 resection occurred in 83 (73%) patients in the MIDP group and in 76 (69%) patients in the ODP group (difference 3.7%, 90% CI -6.2 to 13.6%; p_{non-inferiority} = 0.039). Median lymph node yield was comparable (22.0 [16.0-30.0] vs 23.0 [14.0-32.0] nodes, p = 0.86), as was the rate of intraperitoneal recurrence (41% vs 38%, p = 0.45). Median follow-up was 23.5 (interquartile range 17.0-30.0) months. Other postoperative outcomes were comparable, including median time to functional recovery (5 [95% CI 4.5-5.5] vs 5 [95% CI 4.7-5.3] days; p = 0.22) and overall survival (HR 0.99, 95% CI 0.67-1.46, p = 0.94). Serious adverse events were reported in 23 (18%) of 131 patients in the MIDP group vs 28 (22%) of 127 patients in the ODP group.

Interpretation

This trial provides evidence on the non-inferiority of MIDP compared to ODP regarding radical resection rates in patients with resectable pancreatic cancer. The present findings support the applicability of minimally invasive surgery in patients with resectable left-sided pancreatic cancer.

Funding

Medtronic Covidien AG, Johnson & Johnson Medical Limited, Dutch Gastroenterology Society.

Impact of neoadjuvant chemotherapy on the difficulty and outcomes of laparoscopic and robotic major liver resections for colorectal liver metastases: A propensity-score and coarsened exact-matched controlled study

BACKGROUND

Minimal invasive liver resections are a safe alternative to open surgery. Different scoring systems considering different risks factors have been developed to predict the risks associated with these procedures, especially challenging major liver resections (MLR). However, the impact of neoadjuvant chemotherapy (NAT) on the difficulty of minimally invasive MLRs remains poorly investigated.

METHODS

Patients who underwent laparoscopic and robotic MLRs for colorectal liver metastases (CRLM) performed across 57 centers between January 2005 to December 2021 were included in this analysis. Patients who did or did not receive NAT were matched based on 1:1 coarsened exact and 1:2 propensity-score matching. Pre- and post-matching comparisons were performed.

RESULTS

In total, the data of 5189 patients were reviewed. Of these, 1411 procedures were performed for CRLM, and 1061 cases met the inclusion criteria. After excluding 27 cases with missing data on NAT, 1034 patients (NAT: n = 641; non-NAT: n = 393) were included. Before matching, baseline characteristics were vastly different. Before matching, the morbidity rate was significantly higher in the NAT-group (33.2% vs. 27.2%, p-value = 0.043). No significant differences were seen in perioperative outcomes after the coarsened exact matching. After the propensity-score matching, statistically significant higher blood loss (mean, 300 (SD 128-596) vs. 250 (SD 100-400) ml, p-value = 0.047) but shorter hospital stay (mean, 6 [4-8] vs. 6 [5-9] days, p-value = 0.043) were found in the NAT-group.

CONCLUSION

The current study demonstrated that NAT had minimal impact on the difficulty and outcomes of minimally-invasive MLR for CRLM.

Learning curves in laparoscopic distal pancreatectomy: a different experience for each generation

BACKGROUND

Learning curves of laparoscopic distal pancreatectomy (LDP) are mostly based on 'self-taught' surgeons who acquired sufficient proficiency largely through self-teaching. No learning curves have been investigated for 'trained' surgeons who received training and built on the experience of the 'self-taught' surgeons. This study compared the learning curves and outcome of LDP between 'self-taught' and 'trained' surgeons in terms of feasibility and proficiency using short-term outcomes.

MATERIALS AND METHODS

Data of consecutive patients with benign or malignant disease of the left pancreas who underwent LDP by four 'self-taught' and four 'trained' surgeons between 1997 and 2019 were collected, starting from the first patient operated by a contributing surgeon. Risk-adjusted cumulative sum (RA-CUSUM) analyses were performed to determine phase-1 feasibility (operative time) and phase-2 proficiency (major complications) learning curves. Outcomes were compared based on the inflection points of the learning curves.

RESULTS

The inflection points for the feasibility and proficiency learning curves were 24 and 36 procedures for 'trained' surgeons compared to 64 and 85 procedures for 'self-taught' surgeons, respectively. In 'trained' surgeons, operative time was reduced after completion of the learning curves (230.5-203 min, P= 0.028). In 'self-taught' surgeons, operative time (240-195 min, P ≤0.001), major complications (20.6-7.8%, P= 0.008), and length of hospital stay (9-5 days, P ≤0.001) reduced after completion of the learning curves.

CONCLUSION

This retrospective international cohort study showed that the feasibility and proficiency learning curves for LDP of 'trained' surgeons were at least halved as compared to 'self-taught' surgeons.

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.

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.

Simultaneous resection of colorectal cancer and synchronous liver metastases: what determines the risk of unfavorable outcomes? An international multicenter retrospective cohort study

BACKGROUND

The use of a simultaneous resection (SIMR) in patients with synchronous colorectal liver metastases (sCRLM) has increased over the past decades. However, it remains unclear when a SIMR is beneficial and when it should be avoided. The aim of this retrospective cohort study was therefore to compare the outcomes of a SIMR for sCRLM in different settings, and to assess which factors are independently associated with unfavorable outcomes.

METHODS

To perform this retrospective cohort study, patients with sCRLM undergoing SIMR (2004-2019) were extracted from an international multicenter database, and their outcomes were compared after stratification according to the type of liver and colorectal resection performed. Factors associated with unfavorable outcomes were identified through multivariable logistic regression.

RESULTS

Overall, 766 patients were included, encompassing colorectal resections combined with a major liver resection (n=122), minor liver resection in the anterolateral (n=407), or posterosuperior segments ('Technically major', n=237). Minor and technically major resections, compared to major resections, were more often combined with a rectal resection (29.2 and 36.7 vs. 20.5%, respectively, both P=0.003) and performed fully laparoscopic (22.9 and 23.2 vs. 6.6%, respectively, both P = 0.003). Major and technically major resections, compared to minor resections, were more often associated with intraoperative transfusions (42.9 and 38.8 vs. 20%, respectively, both P = 0.003) and unfavorable incidents (9.6 and 9.8 vs. 3.3%, respectively, both P≤0.063). Major resections were associated, compared to minor and technically major resections, with a higher overall morbidity rate (64.8 vs. 50.4 and 49.4%, respectively, both P≤0.024) and a longer length of stay (12 vs. 10 days, both P≤0.042). American Society of Anesthesiologists grades ≥3 [adjusted odds ratio (aOR): 1.671, P=0.015] and undergoing a major liver resection (aOR: 1.788, P=0.047) were independently associated with an increased risk of severe morbidity, while undergoing a left-sided colectomy was associated with a decreased risk (aOR: 0.574, P=0.013).

CONCLUSIONS

SIMR should primarily be reserved for sCRLM patients in whom a minor or technically major liver resection would suffice and those requiring a left-sided colectomy. These findings should be confirmed by randomized studies comparing SIMR with staged resections.

Robot-Assisted Versus Laparoscopic Distal Pancreatectomy in Patients with Resectable Pancreatic Cancer: An International, Retrospective, Cohort Study

BACKGROUND

Robot-assisted distal pancreatectomy (RDP) is increasingly used as an alternative to laparoscopic distal pancreatectomy (LDP) in patients with resectable pancreatic cancer but comparative multicenter studies confirming the safety and efficacy of RDP are lacking.

METHODS

An international, multicenter, retrospective, cohort study, including consecutive patients undergoing RDP and LDP for resectable pancreatic cancer in 33 experienced centers from 11 countries (2010-2019). The primary outcome was R0-resection. Secondary outcomes included lymph node yield, major complications, conversion rate, and overall survival.

RESULTS

In total, 542 patients after minimally invasive distal pancreatectomy were included: 103 RDP (19%) and 439 LDP (81%). The R0-resection rate was comparable (75.7% RDP vs. 69.3% LDP, p = 0.404). RDP was associated with longer operative time (290 vs. 240 min, p < 0.001), more vascular resections (7.6% vs. 2.7%, p = 0.030), lower conversion rate (4.9% vs. 17.3%, p = 0.001), more major complications (26.2% vs. 16.3%, p = 0.019), improved lymph node yield (18 vs. 16, p = 0.021), and longer hospital stay (10 vs. 8 days, p = 0.001). The 90-day mortality (1.9% vs. 0.7%, p = 0.268) and overall survival (median 28 vs. 31 months, p = 0.599) did not differ significantly between RDP and LDP, respectively.

CONCLUSIONS

In selected patients with resectable pancreatic cancer, RDP and LDP provide a comparable R0-resection rate and overall survival in experienced centers. Although the lymph node yield and conversion rate appeared favorable after RDP, LDP was associated with shorter operating time, less major complications, and shorter hospital stay. The specific benefits associated with each approach should be confirmed by multicenter, randomized trials.

A PRRX1 signature identifies TIM-3 and VISTA as potential immune checkpoint targets in a subgroup of microsatellite-stable colorectal cancer liver metastases

Disease recurrence and drug resistance are major challenges in the clinical management of patients with colorectal cancer liver metastases (CLM), and because tumors are generally microsatellite stable (MSS), responses to immune therapies are poor. The mesenchymal phenotype is overrepresented in treatment resistant cancers and is associated with an immunosuppressed microenvironment. The aim of this work was to molecularly identify and characterize a mesenchymal subgroup of MSS CLM to identify novel therapeutic approaches. We here generated a mesenchymal gene expression signature by analysis of resection specimens from 38 CLM patients using ranked expression level of the epithelial-to-mesenchymal transition related transcription factor PRRX1. Downstream pathway analysis based on the resulting gene signature was performed and independent, publicly available datasets were used to validate the findings. A subgroup comprising 16% of the analyzed CLM samples were classified as mesenchymal, or belonging to the PRRX1high group. Analysis of the PRRX1 signature genes revealed a distinct immunosuppressive phenotype with high expression of immune checkpoints HAVCR2/TIM-3 and VISTA, in addition to the M2 macrophage marker CD163. The findings were convincingly validated in datasets from three external CLM cohorts. Up-regulation of immune checkpoints HAVCR2/TIM-3 and VISTA in the PRRX1high subgroup is a novel finding, and suggests immune evasion beyond the PD-1/PD-L1 axis, which may contribute to poor response to PD-1/PD-L1 directed immune therapy in MSS colorectal cancer. Importantly, these checkpoints represent potential novel opportunities for immune-based therapy approaches in a subset of MSS CLM.

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.

Figures do matter: A literature review of 4587 robotic pancreatic resections and their implications on training

BACKGROUND

The use of robotic assistance in minimally invasive pancreatic resection is quickly growing.

METHODS

We present a systematic review of the literature regarding all types of robotic pancreatic resection (RPR). Our aim is to show for which procedures there is enough experience to permit safe training and provide an estimation of how many centers could serve as teaching institutions.

RESULTS

Sixty-four studies reporting on 4587 RPRs were analyzed. A total of 2598 pancreatoduodenectomies (PD) were reported by 28 centers from Europe (6/28; 21.4%), the Americas (11/28; 39.3%), and Asia (11/28; 39.3%). Six studies reported >100 robot PD (1694/2598; 65.2%). A total of 1618 distal pancreatectomies (DP) were reported by 29 centers from Europe (10/29; 34.5%), the Americas (10/29; 34.5%), and Asia (9/29; 31%). Five studies reported >100 robotic DP (748/1618; 46.2%). A total of 154 central pancreatectomies were reported by six centers from Europe (1/6; 16.7%), the Americas (2/6; 33.3%), and Asia (3/6; 50%). Only 49 total pancreatectomies were reported. Finally, 168 enucleations were reported in seven studies (with a mean of 15.4 cases per study). A single center reported on 60 enucleations (35.7%). Results of each type of robotic procedure are also presented.

CONCLUSIONS

Experience with RPR is still quite limited. Despite high case volume not being sufficient to warrant optimal training opportunities, it is certainly a key component of every successful training program and is a major criterion for fellowship accreditation. From this review, it appears that only PD and DP can currently be taught at few institutions worldwide.

Outcome a decade after laparoscopic and open Nissen fundoplication in children: results from a randomized controlled trial

BACKGROUND

Randomized controlled trials (RCT) comparing long-term outcome after laparoscopic (LF) and open fundoplication (OF) in children are lacking. Here we report recurrence rates and time to recurrence, frequency of re-interventions, use of antisecretory drugs, gastrointestinal symptoms, and patient/parental satisfaction a decade after children were randomized to LF or OF.

METHODS

Cross-sectional long-term follow-up study of a two-center RCT that included patients during 2003-2009. Patients/parents were interviewed and medical charts reviewed for any events that might be related to the fundoplication. If suspicion of recurrence, further diagnostics were performed. Informed consent and ethical approval were obtained.

CLINICALTRIALS

gov: NCT01551134.

RESULTS

Eighty-eight children, 56 (64%) boys, were randomized (LF 44, OF 44) at median 4.4 [interquartile range (IQR) 2.0-8.9] years. 46 (52%) had neurological impairment. Three were lost to follow-up before first scheduled control. Recurrence was significantly more frequent after LF (24/43, 56%) than after OF (13/42, 31%, p = 0.004). Median time to recurrence was 1.0 [IQR 0.3-2.2] and 5.1 [IQR 1.5-9.3] years after LF and OF, respectively. Eight (19%) underwent redo fundoplication after LF and three (7%) after OF (p = 0.094). Seventy patients/parents were interviewed median 11.9 [IQR 9.9-12.8] years postoperatively. Among these, use of anti-secretory drugs was significantly decreased from preoperatively after both LF (94% vs. 35%, p < 0.001) and OF (97% vs. 19%, p < 0.001). Regurgitation/vomiting were observed in 6% after LF and 3% after OF (p = 0.609), and heartburn in 14% after LF and 17% after OF (p = 1.000). Overall opinion of the surgical scars was good in both groups (LF: 95%, OF: 86%, p = 0.610). Patient/parental satisfaction with outcome was high, independent of surgical approach (LF: 81%, OF: 88%, p = 0.500).

CONCLUSIONS

The recurrence rate was higher and recurrence occurred earlier after LF than after OF. Patient/parental satisfaction with outcome after both LF and OF was equally high.

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.

Systematic review and meta-analysis of difficulty scoring systems for laparoscopic and robotic liver resections

INTRODUCTION

The ability to stratify the difficulty of minimally invasive liver resection (MILR) allows surgeons at different phases of the learning curve to tackle cases of appropriate difficulty safely. Several difficulty scoring systems (DSS) have been formulated which attempt to accurately stratify this difficulty. The present study aims to review the literature pertaining to the existing DSS for MILR.

METHODS

We performed a systematic review and metanalysis of the literature reporting on the formulation, supporting data, and comparison of DSS for MILR.

RESULTS

A total of 11 studies were identified which reported on the formulation of unique DSS for MILR. Five of these (Ban, Iwate, Hasegawa, Institut Mutaliste Montsouris [IMM], and Southampton DSS) were externally validated and shown to predict difficulty of MILR via a range of outcome measures. The Ban DSS was supported by pooled data from 10 studies (9 LLR, 1 RLR), Iwate by 10 studies (8 LLR, 2 RLR), Hasegawa by four studies (all LLR), IMM by eight studies (all LLR), and Southampton by five studies (all LLR). There was no clear superior DSS.

CONCLUSION

The existing DSS were all effective in predicting difficulty of MILR. Present studies comparing between DSS have not established a clear superior system, and the five main DSS have been found to be predictive of difficulty in LLR and two of these in RLR.

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.

Benchmarking of robotic and laparoscopic spleen-preserving distal pancreatectomy by using two different methods

BACKGROUND

Benchmarking is an important tool for quality comparison and improvement. However, no benchmark values are available for minimally invasive spleen-preserving distal pancreatectomy, either laparoscopically or robotically assisted. The aim of this study was to establish benchmarks for these techniques using two different methods.

METHODS

Data from patients undergoing laparoscopically or robotically assisted spleen-preserving distal pancreatectomy were extracted from a multicentre database (2006-2019). Benchmarks for 10 outcomes were calculated using the Achievable Benchmark of Care (ABC) and best-patient-in-best-centre methods.

RESULTS

Overall, 951 laparoscopically assisted (77.3 per cent) and 279 robotically assisted (22.7 per cent) procedures were included. Using the ABC method, the benchmarks for laparoscopically assisted and robotically assisted spleen-preserving distal pancreatectomy respectively were: 150 and 207 min for duration of operation, 55 and 100 ml for blood loss, 3.5 and 1.7 per cent for conversion, 0 and 1.7 per cent for failure to preserve the spleen, 27.3 and 34.0 per cent for overall morbidity, 5.1 and 3.3 per cent for major morbidity, 3.6 and 7.1 per cent for pancreatic fistula grade B/C, 5 and 6 days for duration of hospital stay, 2.9 and 5.4 per cent for readmissions, and 0 and 0 per cent for 90-day mortality. Best-patient-in-best-centre methodology revealed milder benchmark cut-offs for laparoscopically and robotically assisted procedures, with operating times of 254 and 262.5 min, blood loss of 150 and 195 ml, conversion rates of 5.8 and 8.2 per cent, rates of failure to salvage spleen of 29.9 and 27.3 per cent, overall morbidity rates of 62.7 and 55.7 per cent, major morbidity rates of 20.4 and 14 per cent, POPF B/C rates of 23.8 and 24.2 per cent, duration of hospital stay of 8 and 8 days, readmission rates of 20 and 15.1 per cent, and 90-day mortality rates of 0 and 0 per cent respectively.

CONCLUSION

Two benchmark methods for minimally invasive distal pancreatectomy produced different values, and should be interpreted and applied differently.

Utility of the Iwate difficulty scoring system for laparoscopic right posterior sectionectomy: do surgical outcomes differ for tumors in segments VI and VII?

INTRODUCTION

The Iwate Score (IS) have not been well-validated for specific procedures, especially for right posterior sectionectomy (RPS). In this study, the utility of the IS was determined for laparoscopic (L)RPS and the effect of tumor location on surgical outcomes was investigated.

METHODS

Post-hoc analysis of 647 L-RPS performed in 40 international centers of which 596L-RPS cases met the inclusion criteria. Baseline characteristics and perioperative outcomes of patients stratified based on the Iwate score were compared to determine whether a correlation with surgical difficulty existed. A 1:1 Mahalanobis distance matching was utilized to investigate the effect of tumor location on L-RPS outcomes.

RESULTS

The patients were stratified into 3 levels of difficulty (31 intermediate, 143 advanced, and 422 expert) based on the IS. When using a stepwise increase of the IS excluding the tumor location score, only Pringle's maneuver was more frequently used in the higher surgical difficulty level (35.5%, 54.6%, and 65.2%, intermediate, advanced, and expert levels, respectively, Z = 3.34, p = 0.001). Other perioperative results were not associated with a statistical gradation toward higher difficulty level. 80 of 85 patients with a segment VI lesion and 511 patients with a segment VII lesion were matched 1:1. There were no significant differences in the perioperative outcomes of the two groups including open conversion, operating time, blood loss, intraoperative blood transfusion, postoperative stay, major morbidity, and mortality.

CONCLUSION

Among patients undergoing L-RPS, the IS did not significantly correlate with most outcome measures associated with intraoperative difficulty and postoperative outcomes. Similarly, tumor location had no effect on L-RPS outcomes.

Live enteroviruses, but not other viruses, detected in human pancreas at the onset of type 1 diabetes in the DiViD study

AIMS/HYPOTHESIS

Enterovirus (EV) infection of pancreatic islet cells is one possible factor contributing to type 1 diabetes development. We have reported the presence of EV genome by PCR and of EV proteins by immunohistochemistry in pancreatic sections. Here we explore multiple human virus species in the Diabetes Virus Detection (DiViD) study cases using innovative methods, including virus passage in cell cultures.

METHODS

Six recent-onset type 1 diabetes patients (age 24-35) were included in the DiViD study. Minimal pancreatic tail resection was performed under sterile conditions. Eleven live cases (age 43-83) of pancreatic carcinoma without diabetes served as control cases. In the present study, we used EV detection methods that combine virus growth in cell culture, gene amplification and detection of virus-coded proteins by immunofluorescence. Pancreas homogenates in cell culture medium were incubated with EV-susceptible cell lines for 3 days. Two to three blind passages were performed. DNA and RNA were extracted from both pancreas tissue and cell cultures. Real-time PCR was used for detecting 20 different viral agents other than EVs (six herpesviruses, human polyomavirus [BK virus and JC virus], parvovirus B19, hepatitis B virus, hepatitis C virus, hepatitis A virus, mumps, rubella, influenza A/B, parainfluenza 1-4, respiratory syncytial virus, astrovirus, norovirus, rotavirus). EV genomes were detected by endpoint PCR using five primer pairs targeting the partially conserved 5' untranslated region genome region of the A, B, C and D species. Amplicons were sequenced. The expression of EV capsid proteins was evaluated in cultured cells using a panel of EV antibodies.

RESULTS

Samples from six of six individuals with type 1 diabetes (cases) and two of 11 individuals without diabetes (control cases) contained EV genomes (p<0.05). In contrast, genomes of 20 human viruses other than EVs could be detected only once in an individual with diabetes (Epstein-Barr virus) and once in an individual without diabetes (parvovirus B19). EV detection was confirmed by immunofluorescence of cultured cells incubated with pancreatic extracts: viral antigens were expressed in the cytoplasm of approximately 1% of cells. Notably, infection could be transmitted from EV-positive cell cultures to uninfected cell cultures using supernatants filtered through 100 nm membranes, indicating that infectious agents of less than 100 nm were present in pancreases. Due to the slow progression of infection in EV-carrying cell cultures, cytopathic effects were not observed by standard microscopy but were recognised by measuring cell viability. Sequences of 5' untranslated region amplicons were compatible with EVs of the B, A and C species. Compared with control cell cultures exposed to EV-negative pancreatic extracts, EV-carrying cell cultures produced significantly higher levels of IL-6, IL-8 and monocyte chemoattractant protein-1 (MCP1).

CONCLUSIONS/INTERPRETATION

Sensitive assays confirm that the pancreases of all DiViD cases contain EVs but no other viruses. Analogous EV strains have been found in pancreases of two of 11 individuals without diabetes. The detected EV strains can be passaged in series from one cell culture to another in the form of poorly replicating live viruses encoding antigenic proteins recognised by multiple EV-specific antibodies. Thus, the early phase of type 1 diabetes is associated with a low-grade infection by EVs, but not by other viral agents.