Echogenic appearance of colorectal liver metastases on intraoperative ultrasonography is associated with survival after hepatic resection

Real-Time Wireless Tumor Tracking in Navigated Liver Resections: An Ex Vivo Feasibility Study

BACKGROUND

Surgical navigation systems generally require intraoperative steps, such as intraoperative imaging and registration, to link the system to the patient anatomy. Because this hampers surgical workflow, we developed a plug-and-play wireless navigation system that does not require any intraoperative steps. In this ex vivo study on human hepatectomy specimens, the feasibility was assessed of using this navigation system to accurately resect a planned volume with small margins to the lesion.

METHODS

For ten hepatectomy specimens, a planning CT was acquired in which a virtual spherical lesion with 5 mm margin was delineated, inside the healthy parenchyma. Using two implanted trackers, the real-time position of this planned resection volume was visualized on a screen, relative to the used tracked pointer. Experienced liver surgeons were asked to accurately resect the nonpalpable planned volume, fully relying on the navigation screen. Resected and planned volumes were compared using CT.

RESULTS

The surgeons resected the planned volume while cutting along its border with a mean accuracy of - 0.1 ± 2.4 mm and resected 98 ± 12% of the planned volume. Nine out of ten resections were radical and one case showed a cut of 0.8 mm into the lesion. The sessions took approximately 10 min each, and no considerable technical issues were encountered.

CONCLUSIONS

This ex vivo liver study showed that it is feasible to accurately resect virtual hepatic lesions with small planned margins using our novel navigation system, which is promising for clinical applications where nonpalpable hepatic metastases have to be resected with small resection margins.

Robot-assisted liver resection: the real benefit so far

BACKGROUND

Minimally invasive liver resection is associated with lower perioperative morbidity and shorter hospital stay. However, the added benefit of the robotic platform over conventional laparoscopy is a matter of ongoing investigation.

PURPOSE

The purpose of this narrative review is to provide an up-to-date and balanced evaluation of the benefits and shortcomings of robotic liver surgery for the modern hepatobiliary surgeon.

CONCLUSIONS

Advantages of a robotic approach to liver resection include a shortened learning curve, the ability to complete more extensive or complex minimally invasive operations, and integrated fluorescence guidance. However, the robotic platform remains limited by a paucity of parenchymal transection devices, complete lack of haptic feedback, and added operating time associated with docking and instrument exchange. Like laparoscopic hepatectomy, robotic hepatectomy may provide patients with more rapid recovery and a shorter hospital stay, which can help offset the substantial costs of robot acquisition and maintenance. The oncologic outcomes of robotic hepatectomy appear to be equivalent to laparoscopic and open hepatectomy for appropriately selected patients.

Can echogenic appearance of neuroendocrine liver metastases on intraoperative ultrasonography predict tumor biology and prognosis?

BACKGROUND

Determining the biologic behavior of neuroendocrine liver metastases (NELM) is important when managing patients with this disease. We sought to define the intraoperative ultrasound (IOUS) characteristics of NELM and correlate with tumor biology and prognosis.

METHODS

Prospective data on patients who underwent IOUS and surgical intervention for NELM were collected, with images digitally recorded, blindly reviewed, and scored for echogenicity. Association between sonographic appearance, clinicopathologic factors and long-term outcomes was analyzed.

RESULTS

A total of 216 lesions from 65 patients were analyzed, with IOUS identifying at least one additional metastasis than preoperative imaging in 41 patients (63.1%) with subsequent change of surgical strategy in 14 patients (21.5%). Most NELM appeared hypoechoic (49.1%) on IOUS, while 38.9% demonstrated hyperechogenicity and 12% isoechogenicity. Hypoechoic lesions were associated with poorly-differentiated tumor (p = 0.005) and smaller tumor size (p = 0.004). Patients with hypoechoic metastases demonstrated significantly shorter median disease-free survival compared with isoechoic or hyperechoic lesions (9 vs 20 vs 18 months, p = 0.049).

DISCUSSION

In addition to improved tumor detection of NELM, IOUS was found to be associated with features of tumor biology, specifically tumor grade and risk-of-recurrence. Echogenicity should be considered a potential prognostic factor in the management of patients with neuroendocrine tumors.

Intraoperative liver ultrasound still affects surgical strategy for patients with colorectal metastases in the modern era

BACKGROUND

The present study was designed to evaluate the role of intraoperative ultrasound (IOUS) in intrahepatic staging and the impact on surgical strategy for patients with colorectal liver metastases (CRLM).

METHODS

The study included 515 patients who had undergone liver resection for CRLM at two tertiary care referral centers. Data from a prospectively collected database were retrospectively analysed. Early intrahepatic recurrence was assessed at 3 and 6 months after resection and was considered as residual disease undetected by IOUS. Performance of imaging modalities was compared by analysis of studies on individual patients.

RESULTS

A total of 1,370 liver metastases were detected preoperatively with a median of 3 imaging modalities. MRI and PET were performed in 51 and 42 % of the patients, respectively. Median number of days between last imaging and surgery was 18. Contrast-enhanced IOUS was performed in 136 patients (26.4 %). Intraoperatively, 293 new nodules were found in 132 patients: on histology 280 were CRLM (17.6 %). Surgical strategy was changed in 140 patients (27.2 %). On multivariate analysis synchronous and bilobar metastases ≥ 3 in number, BMI ≥ 30, and time between last imaging and surgery longer than 18 days resulted in predictive factors indicating new nodules detected by IOUS. Early intrahepatic recurrences were 3.7 and 7.9 % at 3 and 6 months. Performance of CT, MRI, FDG-PET, and intraoperative staging was compared: sensitivity was 63.6, 68.8, 53.6, and 92 % and specificity was 91, 92.3, 95.8, and 97.8 %, respectively

CONCLUSIONS

The use of IOUS continues to be mandatory for correct staging of patients with CRLM undergoing liver resection.

Survival after liver resection in metastatic colorectal cancer: review and meta-analysis of prognostic factors

Background

Hepatic metastases develop in approximately 50% of colorectal cancer (CRC) cases. We performed a review and meta-analysis to evaluate survival after resection of CRC liver metastases (CLMs) and estimated the summary effect for seven prognostic factors.

Methods

Studies published between 1999 and 2010, indexed on Medline, that reported survival after resection of CLMs, were reviewed. Meta-relative risks for survival by prognostic factor were calculated, stratified by study size and annual clinic volume. Cumulative meta-analysis results by annual clinic volume were plotted.

Results

Five- and 10-year survival ranged from 16% to 74% (median 38%) and 9% to 69% (median 26%), respectively, based on 60 studies. The overall summary median survival time was 3.6 (range: 1.7–7.3) years. Meta-relative risks (95% confidence intervals) by prognostic factor were: node positive primary, 1.6 (1.5–1.7); carcinoembryonic antigen level, 1.9 (1.1–3.2); extrahepatic disease, 1.9 (1.5–2.4); poor tumor grade, 1.9 (1.3–2.7); positive margin, 2.0 (1.7–2.5); >1 liver metastases, 1.6 (1.4–1.8); and >3 cm tumor diameter, 1.5 (1.3–1.8). Cumulative meta-analyses by annual clinic volume suggested improved survival with increasing volume.

Conclusion

The overall median survival following CLM liver resection was 3.6 years. All seven investigated prognostic factors showed a modest but significant predictive relationship with survival, and certain prognostic factors may prove useful in determining optimal therapeutic options. Due to the increasing complexity of surgical interventions for CLM and the inclusion of patients with higher disease burdens, future studies should consider the potential for selection and referral bias on survival.

Minimally invasive evaluation and treatment of colorectal liver metastases

Minimally invasive techniques used in the evaluation and treatment of colorectal liver metastases (CRLMs) include ultrasonography (US), computed tomography, magnetic resonance imaging, percutaneous and operative ablation therapy, standard laparoscopic techniques, robotic techniques, and experimental techniques of natural orifice endoscopic surgery. Laparoscopic techniques range from simple staging laparoscopy with or without laparoscopic intraoperative US, through intermediate techniques including simple liver resections (LRs), to advanced techniques such as major hepatectomies. Hereins, we review minimally invasive evaluation and treatment of CRLM, focusing on a comparison of open LR (OLR) and minimally invasive LR (MILR). Although there are no randomized trials comparing OLR and MILR, nonrandomized data suggest that MILR compares favorably with OLR regarding morbidity, mortality, LOS, and cost, although significant selection bias exists. The future of MILR will likely include expanding criteria for resectability of CRLM and should include both a patient registry and a formalized process for surgeon training and credentialing.

The value of intraoperative ultrasound and preoperative imaging, individually and in combination, in liver resection for metastatic colorectal cancer

INTRODUCTION

Liver resection is proved to offer potential long-term survival for colorectal liver metastases (CRLM). Accurate radiological assessment is vital to enable an appropriate surgical approach. The role of intraoperative ultrasound (IOUS) has been controversial. This study was designed to analyse the accuracy of IOUS compared with that of preoperative imaging (POI) in these patients.

MATERIALS AND METHODS

A prospective analysis of 51 consecutive patients who underwent liver resection for CRLM was undertaken. The accuracy of POI and IOUS were correlated and compared with histopathological analysis. Statistical analyses included t-tests, to compare continuous variables, and chi-square and Fisher's exact tests to compare categorical variables. p<0.05 was considered significant

RESULTS

POI correlated with histology in 35 patients (68.6%). The sensitivity and specificity were 82.4% and 86.3% respectively. IOUS correlated with histology in 31 (60.8%) patients. The sensitivity and specificity were 84.3% and 76.5% respectively. There was no difference in accuracy between modalities. The accuracy of POI combined with IOUS correlated with histology in 40 patients (78.4%). The sensitivity and specificity were 88.2% and 84.3% respectively. The accuracy of combined modalities was significantly greater than IOUS or POI alone.

CONCLUSIONS

POI combined with IOUS may significantly increase the diagnostic accuracy of patients undergoing liver resection for CRLM.

Trends in nontherapeutic laparotomy rates in patients undergoing surgical therapy for hepatic colorectal metastases

Surgery is the treatment of choice in selected patients with hepatic colorectal metastases. Despite improvements in preoperative imaging, patients can undergo unnecessary nontherapeutic laparotomy. The aim of this study was to examine trends in nontherapeutic laparotomy rates in patients undergoing planned surgical therapy for hepatic colorectal metastases. Data from 530 operations (461 patients) undergoing potentially curative surgical therapy for colorectal liver metastases between 1994 and 2005 were analyzed. The incidence of nontherapeutic laparotomy was determined and factors associated with nontherapeutic laparotomy were identified. Overall, 49 nontherapeutic laparotomies were performed (9.2%). Higher nontherapeutic laparotomy rates were seen in patients with multiple metastases and tumor size >5 cm (both P < 0.05). Preoperative positron emission tomography (PET) imaging was associated with lower risk of nontherapeutic laparotomy [5.6% versus 12.4%, P = 0.009, odds ratio (OR) = 0.42]. At laparotomy, extrahepatic findings were the reason for nontherapeutic laparotomy in 44.9% of cases. The nontherapeutic laparotomy rate significantly decreased over time (14.9% for 1994-1997 versus 9.6% for 1998-2001 versus 4.7% for 2002-2005; P = 0.003). While patients in each time period were similar with regard to tumor specific factors, utilization of PET imaging (P < 0.001) as well as resection plus ablation (P = 0.004) increased over time. We conclude that prevalence of nontherapeutic laparotomy for patients undergoing surgical exploration for hepatic colorectal metastases has decreased significantly in recent years to less than 5%. The reasons for this trend are probably multifactorial and may include improved preoperative assessment, such as PET imaging, as well as salvage surgical options.