Survival of patients with colorectal liver metastases treated with and without preoperative chemotherapy:Nationwide propensity score-matched study

Introduction: Routine treatment with preoperative systemic chemotherapy (CTx) in patients with colorectal liver metastases (CRLM) remains controversial due to lack of consistent evidence demonstrating associated survival benefits. This study aimed to determine the effect of preoperative CTx on overall survival (OS) compared to surgery alone and to assess hospital and oncological network variation in 5-year OS. Methods: This was a population-based study of all patients who underwent liver resection for CRLM between 2014 and 2017 in the Netherlands. After 1:1 propensity score matching (PSM), OS was compared between patients treated with and without preoperative CTx. Hospital and oncological network variation in 5-year OS corrected for case-mix factors was calculated using an observed/expected ratio. Results: Of 2820 patients included, 852 (30.2%) and 1968 (69.8%) patients were treated with preoperative CTx and surgery alone, respectively. After PSM, 537 patients remained in each group, median number of CRLM; 3 [IQR 2–4], median size of CRLM; 28 mm [IQR 18–44], synchronous CLRM (71.1%). Median follow-up was 80.8 months. Five-year OS rates after PSM for patients treated with and without preoperative chemotherapy were 40.2% versus 38.3% (log-rank P = 0.734). After stratification for low, medium, and high tumour burden based on the tumour burden score (TBS) OS was similar for preoperative chemotherapy vs. surgery alone (log-rank P = 0.486, P = 0.914, and P = 0.744, respectively). After correction for non-modifiable patient and tumour characteristics, no relevant hospital or oncological network variation in five-year OS was observed. Conclusion: In patients eligible for surgical resection, preoperative chemotherapy does not provide an overall survival benefit compared to surgery alone.</p

Practice variation and outcomes of minimally invasive minor liver resections in patients with colorectal liver metastases:a population-based study

Introduction: In 2017, the Southampton guideline stated that minimally invasive liver resections (MILR) should considered standard practice for minor liver resections. This study aimed to assess recent implementation rates of minor MILR, factors associated with performing MILR, hospital variation, and outcomes in patients with colorectal liver metastases (CRLM). Methods: This population-based study included all patients who underwent minor liver resection for CRLM in the Netherlands between 2014 and 2021. Factors associated with MILR and nationwide hospital variation were assessed using multilevel multivariable logistic regression. Propensity-score matching (PSM) was applied to compare outcomes between minor MILR and minor open liver resections. Overall survival (OS) was assessed with Kaplan–Meier analysis on patients operated until 2018. Results: Of 4,488 patients included, 1,695 (37.8%) underwent MILR. PSM resulted in 1,338 patients in each group. Implementation of MILR increased to 51.2% in 2021. Factors associated with not performing MILR included treatment with preoperative chemotherapy (aOR 0.61 CI:0.50–0.75, p &lt; 0.001), treatment in a tertiary referral hospital (aOR 0.57 CI:0.50–0.67, p &lt; 0.001), and larger diameter and number of CRLM. Significant hospital variation was observed in use of MILR (7.5% to 93.0%). After case-mix correction, six hospitals performed fewer, and six hospitals performed more MILRs than expected. In the PSM cohort, MILR was associated with a decrease in blood loss (aOR 0.99 CI:0.99–0.99, p &lt; 0.01), cardiac complications (aOR 0.29, CI:0.10–0.70, p = 0.009), IC admissions (aOR 0.66, CI:0.50–0.89, p = 0.005), and shorter hospital stay (aOR CI:0.94–0.99, p &lt; 0.01). Five-year OS rates for MILR and OLR were 53.7% versus 48.6%, p = 0.21. Conclusion: Although uptake of MILR is increasing in the Netherlands, significant hospital variation remains. MILR benefits short-term outcomes, while overall survival is comparable to open liver surgery. Graphical abstract: [Figure not available: see fulltext.].</p

Ultrasound guidance in navigated liver surgery: toward deep-learning enhanced compensation of deformation and organ motion

Purpose: Accuracy of image-guided liver surgery is challenged by deformation of the liver during the procedure. This study aims at improving navigation accuracy by using intraoperative deep learning segmentation and nonrigid registration of hepatic vasculature from ultrasound (US) images to compensate for changes in liver position and deformation. Methods: This was a single-center prospective study of patients with liver metastases from any origin. Electromagnetic tracking was used to follow US and liver movement. A preoperative 3D model of the liver, including liver lesions, and hepatic and portal vasculature, was registered with the intraoperative organ position. Hepatic vasculature was segmented using a reduced 3D U-Net and registered to preoperative imaging after initial alignment followed by nonrigid registration. Accuracy was assessed as Euclidean distance between the tumor center imaged in the intraoperative US and the registered preoperative image. Results: Median target registration error (TRE) after initial alignment was 11.6 mm in 25 procedures and improved to 6.9 mm after nonrigid registration (p = 0.0076). The number of TREs above 10 mm halved from 16 to 8 after nonrigid registration. In 9 cases, registration was performed twice after failure of the first attempt. The first registration cycle was completed in median 11 min (8:00–18:45 min) and a second in 5 min (2:30–10:20 min). Conclusion: This novel registration workflow using automatic vascular detection and nonrigid registration allows to accurately localize liver lesions. Further automation in the workflow is required in initial alignment and classification accuracy

High versus low dose Stereotactic Body Radiation Therapy for hepatic metastases

Introduction: Stereotactic Body Radiation Therapy (SBRT) is a treatment option for patients with liver metastases. This study evaluated the impact of high versus low dose image-guided SBRT of hepatic metastases. Methods and materials: This is a single-center retrospective study of patients with liver metastases treated with SBRT. For analyses, patients were divided into two groups: ≤100 Gy and >100 Gy near-minimum Biological Effective Doses (BED98%). The main outcomes were local control (LC), toxicity and overall survival (OS). Cox regression analyses were performed to determine prognostic variables on LC and OS. Results: Ninety patients with 97 liver metastases (77% colorectal) were included. Median follow-up was 28.6 months. The two-year LC rates in the ≤100 Gy and >100 Gy BED98% group were 60% (CI: 41–80%) and 90% (CI: 80–100%), respectively (p = 0.004). Grade 3 toxicity occurred in 7% vs 2% in the ≤100 Gy and >100 Gy group (p = 0.23). Two-year OS rates in the ≤100 Gy and >100 Gy group were 48% (CI: 32–65%) and 85% (CI: 73–97%), respectively (p = 0.007). In multivariable Cox regression analyses, group dose and tumor volume were significantly correlated with LC (HR: 3.61; p = 0.017 and HR: 1.01; p = 0.005) and OS (HR: 2.38; p = 0.005 and HR: 1.01; p = <0.0001). Conclusion: High dose SBRT provides significantly better local control and overall survival than low dose SBRT without increasing toxicity. When surgical resection is not feasible, high dose SBRT provides an effective and safe treatment for liver metastases

Ultrasound-based navigation for open liver surgery using active liver tracking

Purpose: Despite extensive preoperative imaging, intraoperative localization of liver lesions after systemic treatment can be challenging. Therefore, an image-guided navigation setup is explored that links preoperative diagnostic scans and 3D models to intraoperative ultrasound (US), enabling overlay of detailed diagnostic images on intraoperative US. Aim of this study is to assess the workflow and accuracy of such a navigation system which compensates for liver motion. Methods: Electromagnetic (EM) tracking was used for organ tracking and movement of the transducer. After laparotomy, a sensor was attached to the liver surface while the EM-tracked US transducer enabled image acquisition and landmark digitization. Landmarks surrounding the lesion were selected during patient-specific preoperative 3D planning and identified for registration during surgery. Endpoints were accuracy and additional times of the investigative steps. Accuracy was computed at the center of the target lesion. Results: In total, 22 navigated procedures were performed. Navigation provided useful visualization of preoperative 3D models and their overlay on US imaging. Landmark-based registration resulted in a mean fiducial registration error of 10.3 ± 4.3 mm, and a mean target registration error of 8.5 ± 4.2 mm. Navigation was available after an average of 12.7 min. Conclusion: We developed a navigation method combining ultrasound with active liver tracking for organ motion compensation, with an accuracy below 10 mm. Fixation of the liver sensor near the target lesion compensates for local movement and contributes to improved reliability during navigation. This represents an important step forward in providing surgical navigation throughout the procedure. Trial Registration: This study is registered in the Netherlands Trial Register (number NL7951)