Rates and patterns of recurrence for percutaneous radiofrequency ablation and open wedge resection for solitary colorectal liver metastasis

Differential cytokine and chemokine expression after ablation vs. resection in colorectal cancer liver metastasis

Background

Surgical resection remains the main curative treatment for colorectal liver metastases (CRLM). Radiofrequency ablation (RFA) is increasingly employed for small, deep lying or otherwise inoperable lesions. However, RFA can induce pro-tumorigenic effects on residual tumor cells, hereby possibly promoting tumor recurrence. Contrastingly, post-RFA tumor debris as an antigen source can also generate anti-cancer immune responses. Utilizing this, current studies on combining RFA with immune therapy appear promising. Here, in an attempt to shed light on this controversy, cytokines involved in inflammation, (lymph)angiogenesis, immune cell recruitment and tumor cell invasion were investigated post-RFA versus post-resection in CRLM patients.

Methods

Cytokine and chemokine serum levels pre-operation, 4 h and 24 h post-operation were analyzed in CRLM patients undergoing RFA (n = 8) or partial hepatectomy (n = 9) using Multiplex immunoassays. Statistical analyses were performed between as well as within individual intervention groups.

Results

Post-RFA, significantly increased levels of acute phase proteins SAA1 and S100A8, IL-6, IL-1Ra, MIP3b (CCL19) and MMP9 were observed along with decreases in Fibronectin, MCP-1 (CCL2), and Tie-2. Post-resection, increased levels of PDGFbb, I309 (CCL1), Apelin, MIF, IL-1b and TNFα were seen. All p-values <0.05.

Conclusion

Pro-inflammatory responses mediated by different cytokines were seen after both RFA and resection, possibly influencing residual tumor cells and tumor recurrence. As both ablation and resection trigger inflammation and immune cell recruitment (albeit via distinct mechanisms), these data suggest that further research may explore combining immune therapy with not only RFA but also resection.

Key message

Analysis of patients' serum after radiofrequency ablation versus resection of colorectal liver metastases (CRLM) showed that these interventions trigger inflammation and immune cell recruitment, via different cyto- and chemokine pathways. This suggests a possible future strategy of combining immune therapy with not only ablative techniques but also with resection of CRLM.

The Management of Oligometastatic Disease in Colorectal Cancer: Present Strategies and Future Perspectives

Oligometastatic disease has been described as an intermediate clinical state between localized cancer and systemically metastasized disease. Recent clinical studies have shown prolonged survival when aggressive locoregional approaches are added to systemic therapies in patients with oligometastases. The aim of this review is to outline the newest options to treat oligometastatic colorectal cancer (CRC), also considering its molecular patterns. We present an overview of the available local treatment strategies, including surgical procedures, stereotactic body radiation therapy (SBRT), thermal ablation, as well as trans-arterial chemoembolization (TACE) and selective internal radiotherapy (SIRT). Moreover, since imaging methods provide crucial information for the early diagnosis and management of oligometastatic CRC, we discuss the role of modern radiologic techniques in selecting patients that are amenable to potentially curative locoregional treatments.

Deep learning model based on contrast-enhanced ultrasound for predicting early recurrence after thermal ablation of colorectal cancer liver metastasis

OBJECTIVES

To develop and validate a deep learning (DL) model based on quantitative analysis of contrast-enhanced ultrasound (CEUS) images that predicts early recurrence (ER) after thermal ablation (TA) of colorectal cancer liver metastasis (CRLM).

METHODS

Between January 2010 and May 2019, a total of 207 consecutive patients with CRLM with 13,248 slice images at three dynamic phases who received CEUS within 2 weeks before TA were retrospectively enrolled in two centres (153 for the training cohort (TC), 32 for the internal test cohort (ITC), and 22 for the external test cohort (ETC)). Clinical and CEUS data were used to develop and validate the clinical model, DL model, and DL combining with clinical (DL-C) model to predict ER after TA. The performance of these models was compared by the receiver operating characteristic curve (ROC) with the DeLong test.

RESULTS

After a median follow-up of 56 months, 49% (99/207) of patients experienced ER. Three key clinical features (preoperative chemotherapy (PC), lymph node metastasis of the primary colorectal cancer (LMPCC), and T stage) were used to develop the clinical model. The DL model yielded better performance than the clinical model in the ETC (AUC: 0.67 for the clinical model, 0.76 for the DL model). The DL-C model significantly outperformed the clinical model and DL model (AUC: 0.78 for the DL-C model in the ETC; both, p < 0.001).

CONCLUSIONS

The model based on CEUS can achieve satisfactory prediction and assist physicians during the therapeutic decision-making process in clinical practice.

KEY POINTS

• This is an exploratory study in which ablation-related contrast-enhanced ultrasound (CEUS) data from consecutive patients with colorectal cancer liver metastasis (CRLM) were collected simultaneously at multiple institutions. • The deep learning combining with clinical (DL-C) model provided desirable performance for the prediction of early recurrence (ER) after thermal ablation (TA). • The DL-C model based on CEUS provides guidance for TA indication selection and making therapeutic decisions.

Microwave Ablation for Colorectal Liver Metastases: A Systematic Review and Pooled Oncological Analyses

Simple Summary

Liver resection for colorectal liver metastases (CRLM) represents the best curative option; however, few patients are candidates for surgery. Microwave ablation (MWA) can be a valid alternative in selected patients. This systematic review reports the oncological results of MWA for CRLM. The literature available on the Web was analyzed for reports concerning MWA for resectable CRLM, published before January 2021. Finally, 12 papers concerning MWA complications, recurrence-free (RF) cases, patients free from local recurrence (FFLR), and overall survival rates (OS) were selected. Global RF rates at 1, 3, and 5 years were 65.1%, 44.6%, and 34.3%, respectively. Global FFLR at 3, 6, and 12 months were 96.3%, 89.6%, and 83.7%, respectively. Global OS rates at 1, 3, and 5 years were 86.7%, 59.6%, and 44.8%, respectively. A better FFLR was achieved with an MWA surgical approach at 3, 6, and 12 months, with 97.1%, 92.7%, and 88.6%, respectively. Surgical MWA for CRLM smaller than 3 cm was a safe and valid option. MWA can be entered as part of the flowchart decision of CRLM curative treatment, especially for use in the parenchyma-sparing strategy and as a complement to surgery.

Abstract

(1) Background: colorectal liver metastases (CRLM) are the most common extra-lymphatic metastases in colorectal cancer; however, few patients are fit for curative surgery. Microwave ablation (MWA) showed promising outcomes in this cohort of patients. This systematic review and pooled analysis aimed to analyze the oncological results of MWA for CRLM. (2) Methods: Following PRISMA guidelines, PubMed, Scopus, EMBASE, Google Scholar, Science Direct, and the Wiley Online Library databases were searched for reports published before January 2021. We included papers assessing MWA, treating resectable CRLM with curative intention. We evaluated the reported MWA-related complications and oncological outcomes as being recurrence-free (RF), free from local recurrence (FFLR), and overall survival rates (OS). (3) Results: Twelve out of 4822 papers (395 patients) were finally included. Global RF rates at 1, 3, and 5 years were 65.1%, 44.6%, and 34.3%, respectively. Global FFLR rates at 3, 6, and 12 months were 96.3%, 89.6%, and 83.7%, respectively. Global OS at 1, 3, and 5 years were 86.7%, 59.6%, and 44.8%, respectively. A better FFLR was reached using the MWA surgical approach at 3, 6, and 12 months, with reported rates of 97.1%, 92.7%, and 88.6%, respectively. (4) Conclusions: Surgical MWA treatment for CRLM smaller than 3 cm is a safe and valid option. This approach can be safely included for selected patients in the curative intent approaches to treating CRLM.

Recurrence and survival following microwave, radiofrequency ablation, and hepatic resection of colorectal liver metastases: A systematic review and network meta-analysis

BACKGROUND

Gold standard for colorectal liver metastases (CRLM) remains hepatic resection (HR). However, patients with severe comorbidities, unresectable or deep-situated resectable CRLM are candidates for ablation. The aim of the study was to compare recurrence rate and survival benefit of the microwave ablation (MWA), radiofrequency ablation (RFA) and HR by conducting the first network meta-analysis.

DATA SOURCES

Systematic search of the literature was conducted in the electronic databases. Both updated traditional and network meta-analyses were conducted and the results were compared between them.

RESULTS

HR cohort demonstrated significantly less local recurrence rate and better 3- and 5-year disease-free (DFS) and overall survival (OS) compared to MWA and RFA cohorts. HR cohort included significantly younger patients and with significantly lower preoperative carcinoembryonic antigen (CEA) by 10.28 ng/mL compared to RFA cohort. Subgroup analysis of local recurrence and OS of solitary and ≤ 3 cm CRLMs did not demonstrate any discrepancies when compared with the whole sample.

CONCLUSIONS

For resectable CRLM the treatment of choice still remains HR. MWA and RFA can be used as a single or adjunct treatment in patients with unresectable CRLM and/or prohibitive comorbidities.

Is percutaneous destruction of a solitary liver colorectal metastasis as effective as a resection?

Backgrounds/Aims

Surgical resection remains the gold standard in the treatment of colorectal liver metastasis. However, when a patient presents with a deep solitary colorectal liver metastasis (S-CLM), the balance between the hepatic volume sacrificed and the S-CLM volume is sometimes clearly unappropriated. Thus, alternatives to surgery, such as operative and percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA), have been developed. This study aimed to identify the prognostic factors affecting survival of patients with S-CLM who undergo curative-intent liver resection or local destruction (RFA or MWA).

Methods

We retrospectively identified 211 patients with synchronous or metachronous S-CLM who underwent either surgical resection (n=182) or local destruction (RFA or MWA; n=29) according to the S-CLM size, location, and surrounding Glissonian structures.

Results

Patients who underwent RFA or MWA had S-CLM of a smaller size than those who underwent resection (mean 19.7 vs. 37.3 mm, p<.01). The 1-, 3-, and 5-year overall survival (OS) rates were 97.4%, 84.9%, and 74.9%, respectively. The 1-, 3-, and 5-year disease-free survival (DFS) rates were 77.9%, 47%, and 38.9%, respectively. S-CLM located in the left liver (p=.04), S-CLM KRAS mutation (p<.01), and extra-hepatic recurrence (p<.01) were identified as independent poor risk factors for overall survival (OS); the OS and DFS were comparable in patients with surgical procedure or percutaneous MWA.

Conclusions

In eligible S-CLM cases, percutaneous MWA seems to be as oncologically efficient as surgical resection and should be include in the decision-tree for treatment strategies.

Safety and Efficacy of Physical Thermal Ablation Combined Sorafenib for Hepatocellular Carcinoma: A Meta-analysis

BACKGROUND AND AIMS

To compare the efficacy and safety of physical thermal ablation (PTA), including radiofrequency ablation (RFA) and microwave ablation (MWA), combined with sorafenib and physical thermal ablation alone for the control and treatment of hepatocellular carcinoma (HCC) according to the available literature.

METHODS

Comprehensive searches were performed on PubMed, Embase, CNKI, the Cochrane Library, China Biomedical Literature Database (known as CBM), Weipu Journal, and Wanfang Database. Meta-analysis was performed using Revman 5.3 software.

RESULTS

A total of 15 studies, consisting of 2,227 HCC patients, were selected and included in this meta-analysis. Compared with the RFA-alone group, the patients in the RFA+sorafenib group had longer 1-, 2-, and 3-year overall survival (all p<0.05), better overall efficacy (p<0.0001), longer radiofrequency interval (p<0.001), and lower 2-year recurrence rate (p=0.02). The 1-year overall survival (p=0.003) and overall efficacy (p=0.002) of the MWA+sorafenib group were also higher than those of the MWA-alone group. The incidences of adverse reactions in the RFA+sorafenib group, such as hand-foot skin reactions (p<0.001), diarrhea and constipation (p=0.0001), hypertension (p=0.009), and alopecia (p<0.001), were significantly higher than those in the RFA-alone group.

CONCLUSIONS

RFA or MWA combined with sorafenib has produced a better therapeutic effect on HCC than physical thermal ablation alone; however, adverse reactions have been obvious. It is necessary to evaluate the safety of combination therapy, and pay close attention to the adverse reactions that develop in patients.

The prognosis of radiofrequency ablation versus hepatic resection for patients with colorectal liver metastases: A systematic review and meta-analysis based on 22 studies

BACKGROUND

Though hepatic resection (HR) is the standard local therapy for patients with colorectal cancer liver metastases (CRLMs), currently, radiofrequency ablation (RFA) may play an alternative role for elderly and vulnerable patients with various organ dysfunctions. This study aims to compare the prognosis of RFA and HR in treatment of CRLMs.

METHODS

A systematic search of PubMed, Embase, Cochrane Library and Web of Science up to October 1, 2020 was conducted for relevant studies that compared the prognosis of RFA with HR in the treatment of CRLMs. The primary outcomes were 30-day mortality, long-term recurrence, overall survival (OS) and disease-free survival (DFS). The secondary outcomes were various factors of OS, recurrence-free survival (RFS), survival, recurrence and complication.

RESULTS

A total of 22 studies including 4385 CRLM patients were identified. There was no significant difference between RFA and HR in 30-day mortality, with a pooled OR of 0.88 (95% CI 0.34-2.29; P = 0.80). CRLM patients undergoing RFA experienced significantly higher incidences of marginal and intrahepatic recurrence than HR, with pooled ORs of 7.09 (95% CI 4.56-11.2; 1251 pts) and 2.02 (95% CI 1.24-3.28; 1038 pts). In addition, RFA showed lower 1-, 3- and 5-yr OS rate than HR with pooled ORs of 0.39, 0.40 and 0.60 respectively. A lower 5-yr DFS rate was also found in RFA than HR group, with a pooled OR of 0.74 (95% CI 0.56-0.97; P = 0.03; 1231 pts). Multivariable analysis showed that tumor size, multiple tumors, age, primary node positive and metachronous metastasis were independent factors of OS, and multiple tumors was also an independent factor of RFS.

CONCLUSIONS

Though the 30-day mortality of RFA was equal to HR, RFA showed a higher recurrence rate and poor long-term survival outcomes for CRLM patients. Tumor size, multiple tumors, age, primary node positive and metachronous metastasis were independent factors of survival. However, the results were limited because of the inequality baseline characteristics between the comparative groups. Randomized or propensity score matching studies should be performed to clarify the effectiveness of RFA and to determine target populations that benefit most from RFA in the future.

Long-term results of percutaneous microwave ablation for colorectal liver metastases

BACKGROUND

Radiofrequency ablation (RFA) has been used for therapy of colorectal liver metastases (CRLMs) several years, with considerable data confirming its safety and efficacy. However, there are few studies focusing on the long-term results of percrtaneous microwave ablation (PMWA) for CRLMs. The aim of this study was to evaluate the long-term survival and prognostic factors in patients with CRLMs undergoing PMWA.

METHODS

We retrospectively analyzed treatment and survival parameters of 210 patients with CRLMs who had received PMWA in a single center from January 2010 to December 2017. Prognostic factors for survival were evaluated by means of univariate and multivariate analyses.

RESULTS

The median follow-up time after PMWA was 48 months. The median overall survival (OS) time were 40.0 months (95% CI, 31.4 to 48.5 months), with 1-, 2, 3-, 4, and 5-year cumulative survival rates of 98.6%, 73.3%, 53.3%, 42.2%, and 32.9%, respectively. Tumor number (P = 0.004; HR: 1.838; CI: 1.213- 2.784), main tumor size (P = 0.017; HR: 1.631; CI: 1.093- 2.436), and serum CEA level (P = 0.032; HR: 1.559; CI: 1.039-2.340) were found as independent predictors of OS. The median OS time for patients with resectable lesions was 60.91 months (95% CI, 51.36 to 70.47 months), with 5-year cumulative survival rates of 53.5%.

CONCLUSION

PMWA is a safe and effective treatment for CRLMs, with a favorable long-term outcome. Multiple lesions, main tumor diameter>3 cm, and serum CEA >30 ng/ml have a significant negative effect on OS.

Can Radiofrequency Ablation Replace Liver Resection for Solitary Colorectal Liver Metastasis? A Systemic Review and Meta-Analysis

Radiofrequency ablation (RFA) can be a favorable option for patients with colorectal liver metastasis (CRLM). However, current reports about the therapeutic efficacy of liver resection (LR) and RFA for colorectal liver metastasis (CRLM) still remain controversial, especially for solitary CRLM. Therefore, this meta-analysis was performed to evaluate the therapeutic efficacy between LR and RFA for solitary CRLM. First, a comprehensive search for published studies was conducted using PubMed, the Cochrane Library Central, and Web of Science. Each study was reviewed and data extracted. In this meta-analysis, 10 studies (11 study arms) were finally included. The meta-analysis was performed using risk ratio (RR) and random effect model or fixed effect model, in which 95% confidence intervals (95% CI) for RR were calculated. The primary outcomes were disease-free survival (DFS) and overall survival (OS) at 1, 3, or 5 years plus complication rate. The results showed that patients treated by LR achieved better PFS and OS than those by RFA, but subgroup analysis and meta-regression displayed that the efficacy of RFA was equivalent to that of LR in solitary CRLM, when conditions were limited to tumors of ≤ 3 cm and fewer synchronous metastasis in the publication years 2011–2018. Meanwhile, RFA achieved lower complication rates when compared with LR. In conclusion, although patients treated by RFA cannot achieve better PFS and OS than those by LR, RFA can be considered a viable treatment option for solitary CRLM, with potentially lower complication rates.

Stereotactic radiofrequency ablation (SRFA) for recurrent colorectal liver metastases after hepatic resection

BACKGROUND

To evaluate the efficacy, safety and overall clinical outcome of multiprobe SRFA as a treatment for recurrent colorectal liver metastases after hepatic resection (HR).

METHODS

A retrospective, single center study carried out between 2006 and 2018. 64 consecutive patients with recurrent or new CRLM after previous HR were treated by SRFA for 217 lesions (median size 2.7 cm, 1-7.5) in 103 ablation sessions. Endpoints consisted of i) technical efficacy ii) complication and mortality rates iii) local and distant recurrence, iv) disease free survival (DFS), and v) overall survival (OS).

RESULTS

213/217 tumors were successfully ablated at initial SRFA (97.7% primary technical efficacy rate). Four tumors required repeat ablation, resulting in a secondary technical efficacy rate of 99.5% (216/217). Local recurrence developed in 25/217 lesions (11.5%). Major complication rate was 5.8% (6/103 sessions) and mortality rate was 1.0% (1/103 ablation sessions), respectively.1-, 3-, and 5- year OS rates from date of first SRFA were 90.1%, 46.2%, and 34.8% (median 33.1 months). DFS rates were 54.2%, 17.2%, and 17.2%, at 1-, 3- and 5- years, respectively (median 13.3 months).

CONCLUSION

SRFA is a safe, feasible and effective option for CRLM after HR with low morbidity levels and favorable clinical outcome.

Strategies for the delay of surgery in the management of resectable hepatobiliary malignancies during the COVID-19 pandemic

Objective

We aimed to review data about delaying strategies for the management of hepatobiliary cancers requiring surgery during the covid-19 pandemic.

Background

Given the covid-19 pandemic, many jurisdictions, to spare resources, have limited access to operating rooms for elective surgical activity, including cancer, thus forcing deferral or cancellation of cancer surgeries. Surgery for hepatobiliary cancer is high-risk and particularly resource-intensive. Surgeons must critically appraise which patients will benefit most from surgery and which ones have other therapeutic options to delay surgery. Little guidance is currently available about potential delaying strategies for hepatobiliary cancers when surgery is not possible.

Methods

An international multidisciplinary panel reviewed the available literature to summarize data relating to standard-of-care surgical management and possible mitigating strategies to be used as a bridge to surgery for colorectal liver metastases, hepatocellular carcinoma, gallbladder cancer, intrahepatic cholangiocarcinoma, and hilar cholangiocarcinoma.

Results

Outcomes of surgery during the covid-19 pandemic are reviewed. Resource requirements are summarized, including logistics and adverse effects profiles for hepatectomy and delaying strategies using systemic, percutaneous and radiation ablative, and liver embolic therapies. For each cancer type, the long-term oncologic outcomes of hepatectomy and the clinical tools that can be used to prognosticate for individual patients are detailed.

Conclusions

There are a variety of delaying strategies to consider if availability of operating rooms decreases. This review summarizes available data to provide guidance about possible delaying strategies depending on patient, resource, institution, and systems factors. Multidisciplinary team discussions should be leveraged to consider patient- and tumour-specific information for each individual case.

Clinical impact of radiofrequency ablation and stereotactic body radiation therapy for colorectal liver metastasis as local therapies for elderly, vulnerable patients

Background and Aim

Surgical resection is the standard local therapy for patients with colorectal liver metastases (CRLM). However, elderly and vulnerable patients sometimes have various organ dysfunctions. We have to conduct nonsurgical local therapies for those patients who might not tolerate surgery or systemic chemotherapy.

Methods

We retrospectively reviewed medical records of 254 patients who underwent local therapies, including surgery, radiofrequency ablation (RFA), and stereotactic body radiation therapy (SBRT), for CRLM from January 2010 to December 2016, at seven tertiary‐care institutions in Japan. This study was designed to include elderly, vulnerable patients who received local therapy for CRLM. For those undergoing liver resection, only those having one or more points of the Charlson comorbidity index (CCI) were enrolled.

Results

Of the total 169 enrolled patients, 122 patients underwent surgery, 42 RFA, and 5 SBRT as the first local therapy for CRLM. Median overall survival from the first local therapy was 5.9 years for the surgery group, 2.7 years for the RFA group, and 3.8 years for the SBRT group. The proportion of the patients with CCI ≧3 was significantly higher in the group of RFA/SBRT than surgery (P < 0.0001). In selected patients with CCI ≧3, there was no difference of the median survival time between the surgery group and the RFA group.

Conclusions

We could have other treatment options to provide nonsurgical local therapies (RFA/SBRT) for elderly, vulnerable CRLM patients who have risks for surgery.

Liver-first approach to stage IV colon cancer with synchronous isolated liver metastases

Background

The only possibility for cure in patients with colon adenocarcinoma (CAC) with isolated liver metastases (ILM) is resection of both primary and metastatic tumors. Little is known about the implication of the sequence in which a colectomy and hepatectomy are performed on outcomes. This study analyzes whether resection sequence impacts clinical outcomes.

Methods

The National Cancer Database was queried for CAC cases with hepatic metastases from 2010-2015 with exclusion of extrahepatic metastases. We compared patients treated with a liver-first approach (LFA) to those treated with a colectomy-first or simultaneous approach using Kaplan Meier and multivariable Cox proportional hazards analysis.

Results

In 21,788 CAC patients identified, the LFA was uncommon (2%), but was associated with higher rates of completion resection of remaining tumor (41% vs. 22%, P<0.001). Patients selected for LFA were younger, less comorbid, and more commonly received upfront chemotherapy (P<0.05). The LFA was associated with increased median survival [34 months, 95% CI (30.5-39.6 months) vs. 24 months, 95% CI (23.7-24.6 months), logrank P<0.001] and decreased risk of death [HR 0.783; 95% CI (0.67-0.89), P=0.001].

Conclusions

The LFA to CAC with synchronous ILM is uncommon but is associated with greater likelihood of receiving chemotherapy prior to surgery and increased survival in selected candidates.

Stereotactic body radiation therapy and radiofrequency ablation for the treatment of liver metastases: How and when?

Limited liver metastases represent a clinical challenge. Surgical approach is the most frequently reported treatment option, however, some patients are not eligible for surgical interventions. Relatively recent technologic advances have permitted the safe use of ablative techniques employed in the cure of hepatic metastases. Among these, radiofrequency ablation (RFA) and stereotactic body radiotherapy (SBRT) have emerged as valid treatments in a significant proportion of patients with intrahepatic oligometastatic disease. This review offers an up-to-date of current available literature on this issue focusing on the use and outcomes of RFA and SBRT, according to the PICO (Population, Intervention, Comparison and Outcomes) criteria.

Management of Liver Oligometastatic Esophageal Cancer: Overview and Critical Analysis of the Different Loco-Regional Treatments

Esophageal cancer (EC) is an aggressive disease that is associated with a poor prognosis. Since metastastic EC is usually considered suitable only for palliative therapy with an estimated 5-year overall survival (OS) less than 5%, the optimal management of patients with liver oligometastatic EC (LOEC) is still undefined. The aim of this review is to provide an overview of the different treatment options for LOEC. A literature search was conducted using PubMed, Embase, and Cochrane to identify articles evaluating different treatment strategies for LOEC. Among 828 records that were identified, 20 articles met the inclusion criteria. These studies included patients who have undergone any type of surgical procedure and/or loco-regional therapy. Liver resection resulted in the best survival for patients with low tumor burden (3 lesions): 5-year OS 30–50% versus 8–12% after only chemotherapy (CHT). The 5-year OS of loco-regional therapies was 23% with a local recurrence risk ranging 0–8% for small lesions (2 to 3 cm). An aggressive multidisciplinary approach for LOEC patients may improve survival. Surgery seems to be the treatment of choice for resectable LOEC. If unfeasible, loco-regional therapies may be considered. In order to better select these patients and offer a chance of cure, prospective trials and a definition of treatment protocols are needed.

Ablation or Resection for Colorectal Liver Metastases? A Systematic Review of the Literature

Background: Successful use of ablation for small hepatocellular carcinomas (HCC) has led to interest in the role of ablation for colorectal liver metastases (CRLM). However, there remains a lack of clarity about the use of ablation for colorectal liver metastases (CRLM), specifically its efficacy compared with hepatic resection. Methods: A systematic review of the literature on ablation or resection of colorectal liver metastases was performed using MEDLINE, Cochrane Library, and Embase until December 2018. The aim of this study was to summarize the evidence for ablation vs. resection in the treatment of CRLM. Results: This review identified 1,773 studies of which 18 were eligible for inclusion. In the majority of the studies, overall survival (OS) and disease-free survival (DFS) were significantly higher and local recurrence (LR) rates were significantly lower in the resection groups. On subgroup analysis of solitary CRLM, resection was associated with improved OS, DFS, and reduced LR. Three series assessed the outcome of resection vs. ablation for technically resectable CRLM, and showed improved outcome in the resection group. In fact, there were no studies showing a survival advantage of ablation compared to resection in the treatment of CRLM. Conclusions: Resection remains the "gold standard" in the treatment of CRLM and should not be replaced by ablation at present. This review supports the use of ablation only as an adjunct to resection and as a single treatment option when resection is not safely possible.

Fluorescent Tissue Assessment of Colorectal Cancer Liver Metastases Ablation Zone: A Potential Real-Time Biomarker of Complete Tumor Ablation

BACKGROUND

This study aimed to evaluate whether rapid fluorescent tissue examination immediately after colorectal cancer liver metastasis (CLM) ablation correlates with standard pathologic and immunohistochemical (IHC) assessments.

METHODS

This prospective, National Institutes of Health-supported study enrolled 34 consecutive patients with 53 CLMs ablated between January 2011 and December 2014. Immediately after ablation, core needle sampling of the ablation zone was performed. Tissue samples were evaluated with fluorescent viability (MitoTracker Red) and nuclear (Hoechst) stains. Confocal microscope imaging was performed within 30 min after ablation. The same samples were subsequently fixed and stained with hematoxylin and eosin (H&E). Identified tumor cells underwent IHC staining for proliferation (Ki67) and viability (OxPhos). The study pathologist, blinded to the H&E and IHC assessment, evaluated the fluorescent images separately to detect viable tumor cells. Sensitivity, specificity, and overall concordance of the fluorescent versus H&E and IHC assessments were calculated.

RESULTS

A total of 63 tissue samples were collected and processed. The overall concordance rate between the immediate fluorescent and the subsequent H&E and IHC assessments was 94% (59/63). The fluorescent assessment sensitivity and specificity for the identification of tumor cells were respectively 100% (18/18) and 91% (41/45).

CONCLUSIONS

The study showed a high concordance rate between the immediate fluorescent assessment and the standard H&E and IHC assessment of the ablation zone. Given the documented prognostic value of ablation zone tissue characteristics for outcomes after ablation of CLM, the fluorescent assessment offers a potential intra-procedural biomarker of complete tumor ablation.

Local recurrence rate in patients with colorectal cancer liver metastasis after wedge resection or percutaneous radiofrequency ablation

PURPOSE

To compare local recurrence (LR) rate in patients with colorectal cancer liver metastasis (CRCLM) after surgical wedge resection (WR) or radiofrequency ablation (RFA) and to investigate predictive factors of LR.

MATERIALS AND METHODS

This single-centre, retrospective, institutional review board-approved study including 43 consecutive patients with 121 metastases treated by WR and 60 patients with 110 metastases treated by RFA between 2007 and 2014 with 23 and 18.5 months of follow-up, respectively. Demographics and tumour characteristics were compared using the unpaired t-test and chi-square test. Predictive factors for LR (lesion size, depth, relation to hepatic vessels, intervention, margin status) were investigated in uni- and multivariate analyses.

RESULTS

Patient and CRCLM characteristics were similar in both groups. Mean lesion size and depth in the WR and RFA groups were 18 mm and 15 mm (p = 0.03), and 19 mm and 26 mm (p < 0.001), respectively. LR showed a trend towards difference in favour of RFA (19% and 10% in the WR and RFA groups, respectively, p = 0.06). Positive margins and lesion depth were predictive factors of LR in the WR group (p = 0.03 and p = 0.02, respectively, on uni- and multivariable analyses). Lesion depth and proximity to a vein increased the risk of positive margins on pathology after WR (p = 0.04 and p < 0.001, respectively). Our analysis did not identify any predictive factors of LR following RFA.

CONCLUSION

Our study showed a trend towards a lower LR rate with RFA compared to WR. Lesions located deep in the liver and/or close to large vessels are at high risk of LR following WR, while curative treatment can be obtained with RFA.

Prognostic value of carcinoembryonic antigen level in patients with colorectal cancer liver metastasis treated with percutaneous microwave ablation under ultrasound guidance

Thermal ablation is an alternative treatment for colorectal cancer liver metastasis (CRLM). However, prognostic factors in patients with CRLM who have undergone microwave ablation (MWA) have not been clearly defined. Therefore, this study aimed to analyze the risk factors associated with early recurrence in patients with CRLM treated with MWA.Herein, we retrospectively analyzed data for 140 patients with CRLM who underwent MWA from 2013 to 2015 in our institution. Patients were grouped by median pretreatment carcinoembryonic antigen (CEA) level into the high CEA level (>3.7 ng/mL) group and low CEA level (≤3.7 ng/mL) group. Variables that might affect overall survival were subjected to univariable and multivariable Cox regression analysis.Our results showed a median progression-free survival (PFS) and median liver progression-free survival (LPFS) of 9 and 11.5 months, respectively, for the 99 CRLM patients analyzed. Both the median PFS duration (7.5 vs. 12.0 months; hazard ratio [HR]: 1.852; 95% confidence interval [CI]: 1.131-3.034; P = .014) and LPFS duration (7.5 vs 14.0 months; HR: 2.117; 95% CI: 1.247-3.593; P = .005) were significantly shorter in the high CEA level group than in the low level group. In multivariable analysis, high CEA level, >3 tumors, and positive node status for the primary tumor were independent factors for PFS, with corrected HRs of 2.11 (95% CI: 1.257-3.555; P = .005), 2.450 (95% CI: 1.420-4.226; P = .001), and 2.265 (95% CI: 1.304-3.935; P = .004), respectively. However, age, tumor size, regional lymph node were not associated with LPFS.CEA level could be a valuable prognostic factor for early recurrence in patients with CRLM after MWA irrespective of the presence of early local recurrence in the liver or disease progression.

Immediate Postablation 18F-FDG Injection and Corresponding SUV Are Surrogate Biomarkers of Local Tumor Progression After Thermal Ablation of Colorectal Carcinoma Liver Metastases

The aim of this study was to determine whether intraprocedural ¹⁸F-FDG PET/CT can be used as a predictor of local tumor progression after percutaneous ablation of colorectal liver metastases. Methods: In this institutional review board-approved prospective study, 39 patients (19 men and 20 women; median age, 56 y) underwent split-dose ¹⁸F-FDG PET/CT-guided ablation followed by immediate biopsy and contrast-enhanced CT imaging of the ablation zone. Binary categorization of biopsy tissues was performed on the basis of the presence of only nonviable coagulation necrosis or viable tumor cells. Minimum ablation margin measurements from contrast-enhanced CT imaging were categorized as 0 mm, 1-4 mm, 5-9 mm, or greater than or equal to 10 mm. SUVs were obtained from PET/CT imaging, and SUV ratios were calculated from 3-dimensional regions of interest located in the ablation zone and surrounding normal liver. All predictive variables (biopsy, minimum margin distance, and SUV ratio) were evaluated as predictors of time to local tumor progression identified on imaging using competing-risks regression models (uni- and multivariate analyses). Results: A total of 62 consecutive ablations were evaluated. The mean SUV ratio was significantly higher for viable tumor-positive immediate postablation biopsies (n = 10) than for tumor-negative biopsies (n = 52) (85.8 ± 92.2 vs. 42.3 ± 45.5) (P = 0.03) and for a minimum margin size of less than 5 mm (n = 15) than for a minimum margin size of greater than or equal to 5 mm (n = 47) (78.5 ± 99.1 vs. 38.3 ± 78.5) (P = 0.01). After a median follow-up period of 22.5 (range, 7-52) months, 23 of 62 ablated tumors showed local tumor progression (37.1%). The local tumor progression rate was significantly higher for viable tumor-positive biopsies (8/10) than for negative biopsies (15/52) (80% vs. 29%) (P = 0.001) and for a minimum margin size of less than 5 mm (9/15) than for a minimum margin size of greater than or equal to 10 mm (2/15) (60% vs. 13%) (P = 0.02) but not 5-9 mm (37.5%; 12/32) (P = 0.5). In a competing-risks analysis, biopsy results (P = 0.07) and the minimum margin size (P = 0.08) were borderline significant, but the SUV ratio was not (P = 0.22). However, for negative biopsy ablations, the minimum margin size and SUV ratio were predictive imaging factors for local tumor progression; subdistribution hazard ratios were 0.564 (0.325-0.978) (P = 0.04) and 1.005 (1.001-1.009) (P = 0.005), respectively. Conclusion: The SUV ratio and minimum margin size can independently predict colorectal metastasis local tumor progression after liver ablation when there are no viable tumor cells on immediate postablation biopsies.

Radiofrequency ablation compared to surgical resection for curative treatment of patients with colorectal liver metastases - a meta-analysis

BACKGROUND

Hepatic resection and ablative treatments, such as RFA are available treatment options for liver tumors. Advantages and disadvantages of these treatment options in patients with colorectal liver metastases need further evaluation. The purpose of this study was to systematically evaluate the role of radiofrequency ablation (RFA) compared to surgery in the curative treatment of patients with colorectal liver metastases (CRLM).

METHODS

A systematic search was performed from MEDLINE, EMBASE and the Cochrane Library for studies directly comparing RFA with resection for CRLM, after which variables were evaluated.

RESULTS

RFA had significantly lower complication rates (OR = 0.44, 95% CI = 0.26-0.75, P = 0.002) compared to resection. However, RFA showed a higher rate of any recurrence (OR = 1.66, 95% CI = 1.15-2.40, P = 0.007), local recurrence (OR = 9.56, 95% CI = 6.85-13.35, P = 0.001), intrahepatic recurrence (OR = 1.96, 95% CI = 1.34-2.87, P = 0.001) and extrahepatic recurrence (OR = 1.21, 95% CI = 0.90-1.63, P = 0.22). Also, 5-year disease-free survival (OR = 2.20, 95% CI = 1.28-3.79, P = 0.005) and overall survival (OR = 2.35, 95% CI = 1.49-3.69, P = 0.001) were significantly lower in patients treated with RFA.

CONCLUSIONS

RFA showed a significantly lower rate of complications, but also a lower survival and a higher rate of recurrence as compared to surgical resection. All the included studies were subject to possible patient selection bias and therefore randomized clinical trials are needed to accurately evaluate these treatment modalities.

Radiofrequency Ablation versus Liver Resection for Colorectal Cancer Liver Metastasis: An Updated Systematic Review and Meta-analysis

Background:

Controversial results about the therapeutic value of radiofrequency ablation (RFA) and liver resection (LR) in the treatment of colorectal cancer liver metastasis (CRCLM) have been reported. Thus, we performed the present meta-analysis to summarize the related clinical evidences.

Methods:

A systematic literature search was conducted using PubMed (Medline), EMBASE, Cochrane Library, and Web of Science, for all years up to April 2016. Pooled analyses of the overall survival (OS), progression-free survival (PFS), and morbidity rates were performed.

Results:

A total of 14 studies were finally enrolled in the meta-analysis. Patients treated by LR gained a longer OS and PFS than those of patients treated by RFA. Patients in the RFA group had lower morbidity rates than those of patients in the LR group. Publication bias analysis revealed that there was no significant publication bias in the meta-analysis.

Conclusions:

Patients with CRCLM gained much more survival benefits from LR than that from RFA. RFA rendered lower rates of morbidities. More well-designed randomized controlled trails comparing the therapeutic value of LR and RFA are warranted.

Treatment Options in Oligometastatic Disease: Stereotactic Body Radiation Therapy - Focus on Colorectal Cancer

BACKGROUND

Improvements in systemic therapy for metastatic colorectal cancer (CRC) have markedly extended survival, rendering local control of metastases to critical organs of increasing importance, especially in the oligometastatic setting where the disease may not yet have acquired the ability to widely disseminate. While surgical resection remains the gold standard for oligometastases in many organs, stereotactic body radiation therapy (SBRT) presents a non-invasive alternative for achieving local control.

METHODS

A literature review was performed to identify and summarize the findings of key prospective and retrospective studies that have shaped the field of SBRT for oligometastases to the lung, liver, and spine with a focus on oligometastases from CRC in particular.

RESULTS

Modern dose-escalated SBRT regimens can achieve 1-year local control rates of 77-100%, 90-100%, and 81-95% for oligometastases involving the lung, liver, and spine, respectively. Rates of grade 3 or greater toxicity with contemporary SBRT techniques are consistently low at <10% in the lung, <5% in the liver, and <2%/8% for neurologic/non-neurologic toxicity in the spine, respectively.

CONCLUSION

SBRT appears safe and effective for treating oligometastases involving the lung, liver, and spine. Randomized trials comparing SBRT to surgical resection and other local therapeutic modalities for the treatment of CRC oligometastases bear consideration.

Radiofrequency Ablation Combined with Hepatic Arterial Chemoembolization Using Degradable Starch Microsphere Mixed with Mitomycin C for the Treatment of Liver Metastasis from Colorectal Cancer: A Prospective Multicenter Study

PURPOSE

This phase II prospective study investigates possible benefits of radiofrequency ablation (RFA) combined with hepatic arterial chemoembolization using degradable starch microsphere (DSM) mixed with mitomycin C (MMC) in non-surgical candidates with colorectal liver metastases.

MATERIALS AND METHODS

This study, approved by the respective institutional review board, included non-surgical candidates with 3 or fewer liver tumors of 3 cm or smaller, or a single lesion 5 cm or smaller. Percutaneous RFA was performed immediately after chemoembolization using DSM-MMC. Primary and secondary endpoints were the local tumor control rate, safety, and 2-year recurrence-free and overall survival rates.

RESULTS

This study examined 25 patients (22 males, 3 females) with 38 tumors of mean maximum diameter of 2.2 ± 0.9 cm (standard deviation) (range 1.0-4.2 cm). Their mean age was 70.2 ± 8.2 years (range 55-82 years). Local tumor progression developed in 3 tumors (7.9%, 3/38) of 3 patients (12%, 3/25) during the mean follow-up of 34.9 ± 9.2 months (range 18.3-50.1 months). The 2-year local tumor control rates were 92.0% [95% confidence interval (CI), 81.4-100%] on a patient basis and 94.6% (95% CI, 87.3-100%) on a tumor basis. The respective 2-year overall and recurrence-free survival rates were 88.0% (95% CI, 75.3-98.5%) and 63.3% (95% CI, 44.2-82.5%), with median survival time of 48.4 months. Fever was the only adverse event requiring treatments in 2 patients (8%).

CONCLUSIONS

This combination therapy is safe, exhibiting strong anticancer effects on colorectal liver metastasis, which might contribute to patient survival.

US-US Fusion Imaging in Radiofrequency Ablation for Liver Metastases

OBJECTIVE

Radiofrequency ablation (RFA) induces gas bubbles in ablation zones, and the ablative margin cannot be evaluated accurately on ultrasound (US) during and immediately after RFA. This study assessed the usefulness of US-US fusion imaging to visualize the ablative margin of RFA for liver metastasis.

METHODS

RFA guided by US-US fusion imaging was performed on 12 targeted tumors in 10 patients. Secondary hepatic malignancies included patients with colorectal cancer (n = 4), breast cancer (n = 2), lung cancer (n = 1), gastrointestinal stromal tumor (n = 1), pancreatic neuroendocrine tumor (n = 1), and adrenocortical carcinoma (n = 1). The maximal diameter of the tumors ranged from 0.8 to 4.0 cm (mean ± SD 1.6 ± 0.9 cm).

RESULTS

The mean number of electrode insertions was 1.6 per session (range 1-3). Technically, effective ablation was achieved in a single session in all patients, and safety ablative margins were confirmed on contrast-enhanced CT for early assessment of tumor response. There were no serious adverse events or procedure-related complications. During the follow-up period (median 220 days, range 31-417 days), none of the patients showed local tumor progression.

CONCLUSION

US-US fusion imaging could show the tumor images before ablation and the ablative area on US in real time. The image overlay of US-US fusion imaging made it possible to evaluate the ablative margin three dimensionally according to the US probe action. Therefore, US-US fusion imaging can contribute to RFA therapy with a safety margin, that is, the so-called precise RFA.

Radiofrequency ablation vs. hepatic resection for resectable colorectal liver metastases

The treatments of resectable colorectal liver metastases (CRLM) are controversial. This study aimed to evaluate the relative efficacy and safety of hepatic resection (HR) and radiofrequency ablation (RFA) for treating resectable CRLM. Between January 2004 and May 2010, the enrolled patients were given hepatic resection (HR group; n=32) or percutaneous RFA (RFA group; n=21) as a first-line treatment for CRLM. All the tumors had a maximum diameter of 3.5 cm and all patients had five or less tumors. The patient background, tumor characteristics, cumulative survival rate and recurrence-free survival rate were assessed in both groups. There were significantly more patients with comorbidities in the RFA group than those in the HR group (17 in RFA group vs. 10 in HR group; P<0.000). The mean maximum tumor diameter in the HR group and RFA group was 2.25±0.68 and 1.89±0.62 cm (P=0.054), and the mean number of tumors was 2.28±1.05 and 2.38±1.12 (P=0.744), respectively. The 1-, 3- and 5-year cumulative survival rates in the HR group were 87.5%, 53.1% and 31.3%, respectively, and those in the RFA group were 85.7%, 38.1% and 14.2%, respectively with the differences being not significant between the two groups (P=0.062). The 1-, 3- and 5-year recurrence-free survival rates in the HR group were 90.6%, 56.3% and 28.1%, respectively, and those in the RFA group were 76.1%, 23.8% and 4.8%, respectively, with the differences being significant between the two groups (P=0.036). In conclusion, as HR has greater efficacy than RFA in the treatment of resectable CRLM, we recommend it as the first option for this malignancy.

Local Control by Radiofrequency Thermal Ablation Increased Overall Survival in Patients With Refractory Liver Metastases of Colorectal Cancer

Radiofrequency thermal ablation (RFA) is widely used for local solitary liver tumor control. However, the benefit of RFA for colorectal cancer with liver metastases, which is refractory to chemotherapy, remains unknown.We retrospectively enrolled 70 consecutive colorectal adenocarcinoma patients, who had synchronous liver metastases, who were refractory to chemotherapy, and whose life expectancy was >6 months, into this study to investigate the outcomes of RFA and associated prognostic factors. RFA was introduced to all of these patients during the enrollment. The time interval from RFA to recurrence of liver metastases and overall survival was recorded. Age, sex, carcinoembryonic antigen level, primary tumor location, postoperative adjuvant chemotherapy regimens, and the size and number of metastatic liver lesions were recorded. Cox regression analysis was used to determine the prognostic significance.Thirty-nine patients accepted RFA during chemotherapy, whereas 31 chose to receive chemotherapy alone. Patients with ≤5 and >5 liver metastases had median survival durations of 28 and 17 months, respectively (P = 0.018). The dominant liver tumor size (<5 vs ≥5 cm) was significantly associated with median survival (30 vs 17 months, respectively; P = 0.038), as was the carcinoembryonic antigen level (35 vs 16 months for ≤200 vs >200 ng/mL respectively; P = 0.029). Besides, radiofrequency thermal ablation plus chemotherapy was associated with a better median overall survival than chemotherapy alone (29 vs 12 months, respectively; P = 0.002). In multivariate analysis, only radiofrequency thermal ablation treatment and number of liver tumors were significant prognostic factors for survival. Our result further revealed that patients treated with radiofrequency thermal ablation had longer progression-free intervals than those treated with chemotherapy alone (18 vs 9 months, respectively; P = 0.001). Hence, radiofrequency thermal ablation is a safe and effective adjunct treatment to chemotherapy.

Colorectal Cancer Liver Metastases: Biopsy of the Ablation Zone and Margins Can Be Used to Predict Oncologic Outcome

Purpose To establish the prognostic value of biopsy of the central and marginal ablation zones for time to local tumor progression (LTP) after radiofrequency (RF) ablation of colorectal cancer liver metastasis (CLM). Materials and Methods A total of 47 patients with 67 CLMs were enrolled in this prospective institutional review board-approved and HIPAA-compliant study between November 2009 and August 2012. Mean tumor size was 2.1 cm (range, 0.6-4.3 cm). Biopsy of the center and margin of the ablation zone was performed immediately after RF ablation (mean number of biopsy samples per ablation zone, 1.9) and was evaluated for the presence of viable tumor cells. Samples containing tumor cells at morphologic evaluation were further interrogated with immunohistochemistry and were classified as either positive, viable tumor (V) or negative, necrotic (N). Minimal ablation margin size was evaluated in the first postablation CT study performed 4-8 weeks after ablation. Variables were evaluated as predictors of time to LTP with the competing-risks model (uni- and multivariate analyses). Results Technical effectiveness was evident in 66 of 67 (98%) ablated lesions on the first contrast material-enhanced CT images at 4-8-week follow-up. The cumulative incidence of LTP at 12-month follow-up was 22% (95% confidence interval [CI]: 12, 32). Samples from 16 (24%) of 67 ablation zones were classified as viable tumor. At univariate analysis, tumor size, minimal margin size, and biopsy results were significant in predicting LTP. When these variables were subsequently entered in a multivariate model, margin size of less than 5 mm (P < .001; hazard ratio [HR], 6.7) and positive biopsy results (P = .008; HR, 3.4) were significant. LTP within 12 months after RF ablation was noted in 3% (95% CI: 0, 9) of necrotic CLMs with margins of at least 5 mm. Conclusion Biopsy proof of complete tumor ablation and minimal ablation margins of at least 5 mm are independent predictors of LTP and yield the best oncologic outcomes. (©) RSNA, 2016.

Ablative and catheter-directed therapies for colorectal liver and lung metastases

Increasing data on treatment of liver metastases with locoregional therapies have solidified the expanding role of interventional radiologists (IRs) in the treatment of liver metastases from colorectal cancer. Ablative approaches such as radiofrequency ablation and microwave ablation have shown durable eradication of tumors. Catheter-directed therapies such as transarterial chemoembolization, drug-eluting beads, yttrium-90 radioembolization, and intra-arterial chemotherapy ports represent potential techniques for managing patients with unresectable liver metastases. Understanding the timing and role of these techniques in multidisciplinary care of patients is crucial. Implementation of IRs for consultation enables better integration of these therapies into patients' overall care.

Radiofrequency ablation of unresectable colorectal liver metastases: trends in management and outcome during a decade at a single center

Background

Radiofrequency ablation (RFA) is widely used for treatment of colorectal liver metastases (CRLM).

Purpose

To evaluate the effect of increased experience in RFA of CRLM on morbidity and survival, and the trends in patient management and outcomes during the last decade.

Material and Methods

Hospital records of the initial 52 consecutive patients who underwent RFA (56 procedures/70 lesions) were retrospectively reviewed. The patients were divided into two groups according to time period of treatment, period I (2001–2006: n = 26) and period II (2007–2011: n = 26).

Results

Concomitant liver resection was performed in 15 patients in each period. Operative morbidity decreased from 47% to 19% (P = 0.047). Most complications were found in patients who underwent a concomitant liver resection and not related to the ablation per se. Local recurrence rate decreased from 19.4% to 12.9% (P = 0.526). At least one risk factor for recurrence was found in patients with local recurrence (n = 11): subcapsular localization (n = 4), tumor size >3 cm and subcapsular localization (n = 2), and perivascular localization (portal veins/hepatic veins) (n = 5). Median overall survival was 32 months in period I and 49 months in period II, whereas estimated 5-year survival was 19% and 36%, respectively (P = 0.09). Adjuvant chemotherapy was given to four patients (15.4%) in period I and 13 patients (50%) in period II (P = 0.017).

Conclusion

RFA alone or in combination with liver resection is a potentially curative treatment to selected patients with CRLM. Over time, the morbidity and survival have improved in RFA of CRLM. Although a possible effect of a learning curve should be taken into consideration in the appraisal of this improvement, it is more likely to be attributable to optimization of indication, development in surgical techniques, and increased use of perioperative chemotherapy.

Thermal ablation of colorectal liver metastases: a position paper by an international panel of ablation experts, The Interventional Oncology Sans Frontières meeting 2013

Objectives

Previous attempts at meta-analysis and systematic review have not provided clear recommendations for the clinical application of thermal ablation in metastatic colorectal cancer. Many authors believe that the probability of gathering randomised controlled trial (RCT) data is low. Our aim is to provide a consensus document making recommendations on the appropriate application of thermal ablation in patients with colorectal liver metastases.

Methods

This consensus paper was discussed by an expert panel at The Interventional Oncology Sans Frontières 2013. A literature review was presented. Tumour characteristics, ablation technique and different clinical applications were considered and the level of consensus was documented.

Results

Specific recommendations are made with regard to metastasis size, number, and location and ablation technique. Mean 31 % 5-year survival post-ablation in selected patients has resulted in acceptance of this therapy for those with technically inoperable but limited liver disease and those with limited liver reserve or co-morbidities that render them inoperable.

Conclusions

In the absence of RCT data, it is our aim that this consensus document will facilitate judicious selection of the patients most likely to benefit from thermal ablation and provide a unified interventional oncological perspective for the use of this technology.

Key Points

• Best results require due consideration of tumour size, number, volume and location.

• Ablation technology, imaging guidance and intra-procedural imaging assessment must be optimised.

• Accepted applications include inoperable disease due to tumour distribution or inadequate liver reserve.

• Other current indications include concurrent co-morbidity, patient choice and the test-of-time approach.

• Future applications may include resectable disease, e.g. for small solitary tumours.

Comparative effectiveness in hepatic malignancies

The benefits of applying comparative effectiveness research (CER) strategies to the management of cancer are important. As the incidence of cancer increases both in the United States and worldwide, accurate analysis of which tests and treatments should be applied in which situations is critical, both in terms of measurable and meaningful clinical outcomes and health care costs. In the last 20 years alone, multiple controversies have arisen in the diagnosis and treatment of primary and metastatic tumors of the liver, making the management of liver malignancies a prime example of CER. Contributing factors to the development of these controversies include improvements in molecular characterization of these diseases and technological advances in surgery and radiology. The relative speed of these advances has outpaced data from clinical trials, in turn making robust data to inform clinical practice lacking. Indeed, many of the current treatment recommendations for the management of liver malignancies are based primarily on retrospective data. We herein review select CER issues concerning select decision-making topics in the management of liver malignancies.

Hepatectomy vs radiofrequency ablation for colorectal liver metastasis: A propensity score analysis

AIM: To compare outcomes from radiofrequency ablation (RFA) and hepatectomy for treatment of colorectal liver metastasis (CRLM).

METHODS: From January 2000 to December 2009, 408 patients underwent curative intent treatment for CRLM. We excluded patients using the criteria: size of CRLM > 3 cm, number of CRLM ≥ 5, percutaneous RFA, follow-up period < 12 mo, double primary cancer, or treatment with both RFA and hepatectomy. We matched 51 patients who underwent RFA with 102 patients who underwent hepatectomy by propensity scores.

RESULTS: The median follow-up period was 45 mo (range, 12 mo to 158 mo). Hepatic recurrence was more frequent in the RFA than the hepatectomy group (P = 0.021) although extrahepatic recurrence curves were similar (P = 0.716). Survival curves of hepatectomy group were better than that of RFA for multiple, large (> 2 cm) CRLM (P = 0.034). However, survival curves were similar for single or small (≤ 2 cm) CRLM (P = 0.714, P = 0.740).

CONCLUSION: Hepatectomy is better than RFA for the treatment of CRLM. However, RFA might be suitable for selected patients with single, small (≤ 2 cm) CRLM.

Minimally invasive local therapies for liver cancer

Primary and metastatic liver tumors are an increasing global health problem, with hepatocellular carcinoma (HCC) now being the third leading cause of cancer-related mortality worldwide. Systemic treatment options for HCC remain limited, with Sorafenib as the only prospectively validated agent shown to increase overall survival. Surgical resection and/or transplantation, locally ablative therapies and regional or locoregional therapies have filled the gap in liver tumor treatments, providing improved survival outcomes for both primary and metastatic tumors. Minimally invasive local therapies have an increasing role in the treatment of both primary and metastatic liver tumors. For patients with low volume disease, these therapies have now been established into consensus practice guidelines. This review highlights technical aspects and outcomes of commonly utilized, minimally invasive local therapies including laparoscopic liver resection (LLR), radiofrequency ablation (RFA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), irreversible electroporation (IRE), and stereotactic body radiation therapy (SBRT). In addition, the role of combination treatment strategies utilizing these minimally invasive techniques is reviewed.

Outcomes of microwave ablation for colorectal cancer liver metastases: a single center experience

BACKGROUND AND OBJECTIVES

Surgical management of colorectal cancer liver metastases continues to evolve to optimize oncologic outcomes while maximizing parenchymal preservation. Long-term data after intraoperative microwave ablation are limited. This study investigates outcomes and patterns of recurrence in patients who underwent intraoperative microwave ablation.

METHODS

A retrospective analysis of 33 patients who underwent intraoperative microwave ablation of colorectal cancer liver metastases from 2009 to 2013 at our institution was performed. Perioperative and long-term data were reviewed to determine outcomes and patterns of recurrence.

RESULTS

A total of 49 tumors were treated, ranging 0.5-5.5 cm in size. Median Clavien-Dindo classification was one. Median follow-up was 531 days, with 13 (39.4%) patients presenting with a recurrence. Median time to first recurrence was 364 days. In those patients, 1 (7.8%) presented with an isolated local recurrence in the liver. Only 1 of 7 ablated tumors greater than 3 cm recurred (14.3%). Overall survival was 35.2% at 4 years, with a 19.3% disease-free survival at 3.5 years. No perioperative variables predicted systemic or local recurrence.

CONCLUSION

Intraoperative microwave ablation is a safe and effective modality for use in the treatment of colorectal cancer liver metastases in tumors as large as 5.5 cm in size.

Ablative technologies for hepatocellular, cholangiocarcinoma, and metastatic colorectal cancer of the liver

A wide array of ablation technologies, in addition to the progressive sophistication of imaging technologies and percutaneous, laparoscopic, and open surgical techniques, have allowed us to expand treatment options for patients with liver tumors. In this article, technical considerations of chemical and thermal ablations and their application in hepatic oncology are reviewed.

Optimal management of colorectal liver metastases in older patients: a decision analysis

BACKGROUND

Comparative trials evaluating management strategies for colorectal cancer liver metastases (CLM) are lacking, especially for older patients. This study developed a decision-analytic model to quantify outcomes associated with treatment strategies for CLM in older patients.

METHODS

A Markov-decision model was built to examine the effect on life expectancy (LE) and quality-adjusted life expectancy (QALE) for best supportive care (BSC), systemic chemotherapy (SC), radiofrequency ablation (RFA) and hepatic resection (HR). The baseline patient cohort assumptions included healthy 70-year-old CLM patients after a primary cancer resection. Event and transition probabilities and utilities were derived from a literature review. Deterministic and probabilistic sensitivity analyses were performed on all study parameters.

RESULTS

In base case analysis, BSC, SC, RFA and HR yielded LEs of 11.9, 23.1, 34.8 and 37.0 months, and QALEs of 7.8, 13.2, 22.0 and 25.0 months, respectively. Model results were sensitive to age, comorbidity, length of model simulation and utility after HR. Probabilistic sensitivity analysis showed increasing preference for RFA over HR with increasing patient age.

CONCLUSIONS

HR may be optimal for healthy 70-year-old patients with CLM. In older patients with comorbidities, RFA may provide better LE and QALE. Treatment decisions in older cancer patients should account for patient age, comorbidities, local expertise and individual values.

Liver-directed therapies in metastatic colorectal cancer

Colorectal cancer (CRC) is a major health concern in the United States (US) with over 140,000 new cases diagnosed in 2012. The most common site for CRC metastases is the liver. Hepatic resection is the treatment of choice for colorectal liver metastases (CLM), with a 5-year survival rate ranging from 35% to 58%. Unfortunately, only about 20% of patients are eligible for resection. There are a number of options for extending resection to more advanced patients including systemic chemotherapy, portal vein embolization (PVE), two stage hepatectomy, ablation and hepatic artery infusion (HAI). There are few phase III trials comparing these treatment modalities, and choosing the right treatment is patient dependent. Treating hepatic metastases requires a multidisciplinary approach and knowledge of all treatment options as there continues to be advances in management of CLM. If a patient can undergo a treatment modality in order to increase their potential for future resection this should be the primary goal. If the patient is still deemed unresectable then treatments that lengthen disease-free and overall-survival should be pursued. These include chemotherapy, ablation, HAI, chemoembolization, radioembolization (RE) and stereotactic radiotherapy.

The use of PET-MRI in the follow-up after radiofrequency- and microwave ablation of colorectal liver metastases

Background

Thermal ablation of colorectal liver metastases (CRLM) may result in local progression, which generally appear within a year of treatment. As the timely diagnosis of this progression allows potentially curative local treatment, an optimal follow-up imaging strategy is essential. PET-MRI is a one potential imaging modality, combining the advantages of PET and MRI. The aim of this study is evaluate fluorine-18 deoxyglucose positron emission tomography (FDG) PET-MRI as a modality for detection of local tumor progression during the first year following thermal ablation, as compared to the current standard, FDG PET-CT. The ability of FDG PET-MRI to detect new intrahepatic lesions, and the extent to which FDG PET-MRI alters clinical management, inter-observer variability and patient preference will also be included as secondary outcomes.

Methods/Design

Twenty patients undergoing treatment with radiofrequency or microwave ablation for (recurrent) CRLM will be included in this prospective trial. During the first year of follow-up, patients will be scanned at the VU University Medical Center at 3-monthly intervals using a 4-phase liver CT, FDG PET-CT and FDG PET-MRI. Patients treated with chemotherapy <6 weeks prior to scanning or with a contra-indication for MRI will be excluded. MRI will be performed using both whole body imaging (mDixon) and dedicated liver sequences, including diffusion-weighted imaging, T1 in-phase and opposed-phase, T2 and dynamic contrast-enhanced imaging. The results of all modalities will be scored by 4 individual reviewers and inter-observer agreement will be determined. The reference standard will be histology or clinical follow-up. A questionnaire regarding patients’ experience with both modalities will also be completed at the end of the follow-up year.

Discussion

Improved treatment options for local site recurrences following CRLM ablation mean that accurate post-ablation staging is becoming increasingly important. The combination of the sensitivity of MRI as a detection method for small intrahepatic lesions with the ability of FDG PET to visualize enhanced metabolism at the ablation site suggests that FDG PET-MRI could potentially improve the accuracy of (early) detection of progressive disease, and thus allow swifter and more effective decision-making regarding appropriate treatment.

Trial registration

Trial registration number: NCT01895673

Patterns of recurrence following selective intraoperative radiofrequency ablation as an adjunct to hepatic resection for colorectal liver metastases

BACKGROUND AND OBJECTIVES

The purpose of this study was to analyze the patterns of recurrence following intraoperative radiofrequency ablation (RFA) combined with hepatic resection for patients with colorectal liver metastases (CLM).

METHODS

Patients undergoing liver resection (with or without RFA) for CLM were examined. Rates and patterns of disease recurrence, as well as overall survival were assessed using Kaplan-Meier and Cox analyses.

RESULTS

A total of 174 patients underwent liver resection for CLM (150 without and 24 with intraoperative RFA). RFA was used to treat 41 tumors (median 1.6 cm). The 3-year overall survival was 65.5% and 61.4% (adjusted HR 1.02, 95% CI 0.55-1.88). Median recurrence-free survival was 7.4 versus 12.7 months with RFA versus non-RFA, respectively (adjusted HR 1.51, 95% CI 0.94-4.42). On multivariate analysis, neither survival nor recurrence-free survival was significantly associated with RFA. In total, there were two RFA ablation zone local failures. An ablation site recurrence was the sole site in one patient (4.2%).

CONCLUSION

RFA was used as an adjunct to resection in patients with greater disease burden. Despite this, RFA was not significantly associated with a higher risk of local failure and was not associated with worse survival, when compared with liver resection alone.

Recurrence location after resection of colorectal liver metastases influences prognosis

AIM

To assess the impact of first recurrence location on survival following surgery of colorectal liver metastases.

METHODS

A total of 265 consecutive patients with colorectal liver metastases undergoing liver surgery (2000-2011) were categorized according to first site of tumor recurrence. Time to recurrence (TTR) and overall survival (OS) were determined. Uni- and multivariate analysis were performed to identify factors associated with TTR and OS.

RESULTS

Median TTR was 1.16 years following liver resection, and 0.56 years following radiofrequency ablation (RFA). Intrahepatic recurrence following liver resection resulted in a significantly shorter median TTR compared to extrahepatic recurrence. Intrapulmonary recurrence was associated with superior survival compared to other recurrence locations. Such patterns were not observed in the RFA-treated group. Multivariate analysis identified the type of surgical treatment and extra-hepatic first-site recurrence (other than lung) as independent predictors for OS. Pre-operative chemotherapy and simultaneous intrahepatic and extrahepatic recurrence were independent predictors for both TTR and OS.

CONCLUSIONS

Patients with intrahepatic recurrence following liver resection have a significantly shorter TTR and OS when compared to patients developing extrahepatic recurrence. Pulmonary recurrence following resection is associated with longer survival. Simultaneous intra- and extrahepatic recurrence is an independent prognostic factor for TTR and OS.

Stereotactic ablative radiotherapy for oligometastatic disease in liver

Liver metastasis in solid tumors, including colorectal cancer, is the most frequent and lethal complication. The development of systemic therapy has led to prolonged survival. However, in selected patients with a finite number of discrete lesions in liver, defined as oligometastatic state, additional local therapies such as surgical resection, radiofrequency ablation, cryotherapy, and radiotherapy can lead to permanent local disease control and improve survival. Among these, an advance in radiation therapy made it possible to deliver high dose radiation to the tumor more accurately, without impairing the liver function. In recent years, the introduction of stereotactic ablative radiotherapy (SABR) has offered even more intensive tumor dose escalation in a few fractions with reduced dose to the adjacent normal liver. Many studies have shown that SABR for oligometastases is effective and safe, with local control rates widely ranging from 50% to 100% at one or two years. And actuarial survival at one and two years has been reported ranging from 72% to 94% and from 30% to 62%, respectively, without severe toxicities. In this paper, we described the definition and technical aspects of SABR, clinical outcomes including efficacy and toxicity, and related parameters after SABR in liver oligometastases from colorectal cancer.

Role of stereotactic body radiotherapy for oligometastasis from colorectal cancer

Systemic chemotherapy has enabled prolongation of survival in patients with stage IV colorectal cancer. This has subsequently increased the relative significance of local therapy for patients with oligometastases because they can be cured by removal of oligometastatic lesions. One of the most frequently reported tumor histologies for oligometastases is colorectal cancer. Resection is the standard therapy in most settings of oligometastases. Recently, studies have shown that stereotactic body radiotherapy (SBRT) may become a treatment option that provides high local control with minimal morbidity. Two-year local control rates following SBRT for hepatic and pulmonary oligometastases are almost over 80% and are even higher for patients treated with high-dose regimens. The indications of SBRT for other metastatic sites or conditions include isolated lymph nodes, spinal and adrenal metastasis, and post-surgical pelvic recurrence. Many retrospective studies have indicated that SBRT for various lesions results in good outcomes with low morbidity, both in the curative and palliative setting. However, few reports with a high level of evidence have indicated the efficacy of SBRT compared to standard therapy. Hereafter, the optimal indication of SBRT needs to be prospectively investigated to obtain convincing evidence.

Locally ablative therapies for primary and metastatic liver cancer

Locally ablative therapies have an increasing role in the effective multidisciplinary approach towards the treatment of both primary and metastatic liver tumors. In patients who are not considered surgical candidates and have low volume disease, these therapies have now become established into consensus practice guidelines. A large range of therapeutic options exist including percutaneous ethanol injection (PEI), radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation, percutaneous laser ablation (PLA), irreversible electroporation (IRE), stereotactic body radiation therapy (SBRT) and high intensity focused ultrasound (HIFU); each having benefits and drawbacks. The greatest body of evidence supporting clinical utility in the liver currently exists for RFA, with PEI having fallen out of favor. MWA, IRE, SBRT and HIFU are relatively nascent technologies, and outcomes data supporting their use is promising. Future directions of ablative therapies include tandem approaches to improve efficacy in the treatment of liver tumors.

Radiofrequency ablation for colorectal liver metastases

The management of hepatic metastases from colorectal cancer (HMCRC) is multimodal including chemotherapy, surgical resection, radiation therapy, and focused destruction technologies. Radiofrequency ablation (RFA) is the most commonly used focused destruction technology. It represents a therapeutic option that may be potentially curative in cases where surgical excision is contra-indicated. It also increases the number of candidates for surgical resection among patients whose liver metastases were initially deemed unresectable. This article explains the techniques, indications, and results of radiofrequency ablation in the treatment of hepatic colorectal metastases.

Impact of treatment modality and number of lesions on recurrence and survival outcomes after treatment of colorectal cancer liver metastases

BACKGROUND

Ablative strategies have been used to treat and facilitate hepatic resection (HR) in patients with otherwise unresectable colorectal liver metastases (CLM). We evaluated the efficacy of HR, concomitant HR and ablation and isolated ablation on recurrence and survival outcomes after treatment of CLM in patients with 1-4 and ≥5 lesions, respectively.

METHODS

A retrospective review of a prospectively collected hepatobiliary surgery database was performed on patients who underwent treatment for isolated CLM between 1990 and 2010. Pre-operative and treatment characteristics were compared between patients who underwent HR, concomitant HR and ablation and ablation alone. The impact of treatment modality on survival and recurrence outcomes was determined.

RESULTS

A total of 701 patients met inclusion criteria; 550 patients (78%) had 1-4 lesions and 151 patients (22%) had ≥5 lesions. Overall median survival for the entire cohort was 35 months with 5- and 10-year survival of 33% and 20%, respectively. Overall median and 5-year recurrence-free survival (RFS) was 13 months and 21%, respectively. For patients with 1-4 lesions, median survival was 37 months with 5-year survival of 36%. Stratified by procedure type, 5-year survival was 41% in patients who underwent HR, 35% in patients who underwent concomitant HR and ablation and 13% in patients who underwent ablation alone (P<0.001). For patients with ≥5 lesions, median survival was 28 months with 5-year survival of 23% without difference between treatment groups (P=0.078).

CONCLUSIONS

HR appears to be the most effective strategy for patients with 1-4 lesions. When ≥5 lesions are present, ablative strategies are useful in facilitating HR in otherwise unresectable patients.

Comparative analysis of radiofrequency ablation and resection for resectable colorectal liver metastases

AIM: To evaluate the therapeutic efficacy of radiofrequency ablation (RFA) for resectable colorectal liver metastases (CRLM) compared with that of resection.

METHODS: Between June 2004 and June 2009, we retrospectively analyzed 29 patients with resectable CRLMs; 17 patients underwent RFA, and 12 underwent hepatic resection. All of the patients were informed about the treatment modalities and were allowed to choose either of them. RFA including an intraoperative approach was performed by a radiologist; otherwise, hepatic resection was performed by a surgeon. Comparative analysis of the two groups was performed, including comparisons of gender, age, and clinical outcomes, such as primary tumor stage and survival rates.

RESULTS: The mean tumor size was significantly larger in the resection group (3.59 cm vs 2.02 cm, P < 0.01), and the 5-year overall survival (OS) rate for all patients was 44.7%. There was no difference in the 5-year OS rates between the RFA and resection groups (37.8% vs 66.7%). Univariate analysis indicated significantly lower 5-year OS rates for patients with a tumor size > 3 cm. The 5-year disease-free survival (DFS) rates were 17.6% and 22.2% in the RFA and resection groups, respectively (P = 0.119). Univariate analysis revealed that in cases of male gender, age > 65 years, T stage < IV, absence of lymphatic metastasis, and tumor size > 3 cm, RFA resulted in significantly inferior 5-year DFS rates compared with surgical resection.

CONCLUSION: Surgical resection revealed superior outcomes in the treatment of resectable CRLMs, particularly in cases with a hepatic tumor size > 3 cm.