Radiofrequency ablation for hepatocellular carcinoma and metastatic liver tumors: a comparative study

Role of diffusion-weighted imaging in response prediction and evaluation after high dose rate brachytherapy in patients with colorectal liver metastases

BACKGROUND

The aim of the study was to assess the role of diffusion-weighted imaging (DWI) to evaluate treatment response in patients with liver metastases of colorectal cancer.

PATIENTS AND METHODS

In this retrospective, observational cohort study, we included 19 patients with 18 responding metastases (R-Mets; follow-up at least one year) and 11 non-responding metastases (NR-Mets; local tumor recurrence within one year) who were treated with high-dose-rate brachytherapy (HDR-BT) and underwent pre- and post-interventional MRI. DWI (qualitatively, mean apparent diffusion coefficient [ADCmean], ADCmin, intraindividual change of ADCmean and ADCmin) were evaluated and compared between pre-interventional MRI, first follow-up after 3 months and second follow-up at the time of the local tumor recurrence (in NR-Mets, mean: 284 ± 122 d) or after 12 months (in R-Mets, mean: 387+/-64 d). Sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) for detection of local tumor recurrence were calculated on second follow up, evaluating (1) DWI images only, and (2) DWI with Gd-enhanced T1-weighted images on hepatobiliary phase (contrast-enhanced [CE] T1-weight [T1w] hepatobiliary phase [hb]).

RESULTS

ADCmean significantly increased 3 months after HDR-BT in both groups (R-Mets: 1.48 ± 0.44 and NR-Mets: 1.49 ± 0.19 x 10-3 mm2;/s, p < 0.0001 and p = 0.01), however, intraindividual change of ADCmean (175% vs.127%, p = 0.03) and ADCmin values (0.44 ± 0.24 to 0.82 ± 0.58 x 10-3 mm2/s) significantly increased only in R-Mets (p < 0.0001 and p < 0.001). ADCmin was significant higher in R-Mets compared to NR-Mets on first follow-up (p = 0.04). Sensitivity (1 vs. 0.72), specificity (0.94 vs. 0.72), PPV (0.91 vs. 0.61) and NPV (1 vs. 0.81) could be improved by combining DWI with CE T1w hb compared to DWI only.

CONCLUSIONS

DW-MRI seems to be helpful in the qualitative and quantitative evaluation of treatment response after HDR-BT of colorectal metastases in the liver.

Single-centre retrospective review of risk factors for local tumour progression and complications in radiofrequency ablation of 555 hepatic lesions

INTRODUCTION

This study aimed to assess safety, local tumour progression (LTP) and risk factors for LTP after radiofrequency ablation (RFA) of liver tumours in a single centre.

METHODS

All consecutive patients treated with RFA for liver tumours between January 2009 and October 2012 were included. Previously treated lesions that progressed were excluded. Using electronic medical records, the following data was captured: patient demographics, pre-procedural laboratory results, Child-Pugh status, tumour characteristics, development of tumoral seeding, RFA complications and LTP. Possible risk factors for LTP were identified using Cox regression.

RESULTS

In total, 555 liver tumours were treated in 337 patients. 483 (87.0%) hepatocellular carcinomas, 52 (9.4%) colorectal metastases and 20 (3.6%) other tumour types were treated. Mean tumour size was 2.1 ± 1.1 (range 0.4-6.8) cm. Mean follow-up duration was 387 days. 416 (75.0%) lesions had no LTP at the last imaging. 70 (12.6%) patients had minor complications requiring observation, while 7 (1.3%) patients had significant complications requiring prolonged hospitalisation or further interventions. Only one case of tumour seeding was detected. Using multivariate Cox regression, the following factors were statistically significant in predicting LTP: hilar location (relative ratio [RR] 3.988), colorectal metastases (RR 2.075), size (RR 1.290) and younger age (RR 0.982).

CONCLUSION

RFA of liver tumours is safe and effective, with a low significant complication rate of 1.3%. Hilar lesions are most prone to LTP, followed by lesions that were larger in size and colorectal metastases. 75.0% of patients showed no LTP at the last follow-up.

Radiofrequency ablation versus hepatic resection for the treatment of early-stage hepatocellular carcinoma meeting Milan criteria: a systematic review and meta-analysis

Current options for the treatment of the early-stage HCC conforming to the Milan criteria consist of liver transplantation, hepatic resection (HR), transcatheter arterial chemoembolization (TACE) and radiofrequency ablation (RFA) .Whether HR or RFA is the better treatment for early HCC has long been debated. The aim of our paper is to compare the therapeutic effects of radiofrequency ablation (RFA) and hepatic resection (HR) in the treatment of early-stage hepatocellular carcinoma (HCC). Controlled trials evaluating the efficacy between RFA and HR for the treatment of early-stage HCC published before June 2013 were searched electronically using MEDLINE, PubMed, Cochrane Library, and EMBASE databases. Using inclusion and exclusion criteria, two randomized controlled trials and 10 nonrandomized controlled trials were included in the meta- analysis. The results showed that the 3,5-year overall survival rates and 1,3,5 disease-free survival rates were significantly lower after RFA than after HR. However, complications after treatment were less common and the length of hospital stay was significantly shorter after RFA. Additionally, there was no significant difference in the 1-year overall survival rate between RFA and HR. The conclusions of the results show that the difference in the short-term effectiveness of RFA and HR in the treatment of small HCC is not notable, but the long-term efficacy of HR is better than that of RFA. However, HR is associated with more complications and a longer hospital stay.

Ablation for hepatocellular carcinoma: validating the 3-cm breakpoint

BACKGROUND

Although many previous studies on local ablation outcomes for hepatocellular carcinoma (HCC) have dichotomized tumor size with a 3-cm cutoff to determine prognostic significance, a growing number of reports describe excellent outcomes for larger tumors. To address the logic of this 3-cm cutoff beyond small single-center experiences, we stratified patients by 1-cm tumor size intervals and hypothesized that disease-specific survival (DSS) would not vary significantly between adjacent groups.

METHODS

Patients treated with local ablation for T1 HCC (≤8 cm) were identified from the surveillance, epidemiology, and end results database (2004-2008). Log-rank tests and multivariable Cox proportional hazards models were used to compare DSS curves of adjacent study groups.

RESULTS

There were 1,083 patients included in the study (26 % female, median age: 62 years). The 3-year DSS was significantly lower in patients with 3- to 4-cm tumors compared to 2- to 3-cm tumors (58 vs. 72 %, p = 0.002). In adjusted models, DSS did not vary significantly between any size intervals up to 3 cm. Patients with 3- to 4-cm tumors, however, had a poorer prognosis compared with patients with 2- to 3-cm tumors (hazard ratio: 1.6, 95 % confidence interval: 1.18-2.18, p = 0.002). DSS also fell when tumor size increased from 5-6 to 6-7 cm (53 vs. 21 %, 0.006).

CONCLUSIONS

This study emphasizes the 3-cm size, and possibly the 6-cm size, as informative predictive thresholds when ablating HCC, because variability of DSS occurred specifically at these tumor sizes. Future research in this field should either adopt a 3-cm breakpoint or provide evidence for alternative thresholds.

Thermal ablation of unresectable liver tumors: factors associated with partial ablation and the impact on long-term survival

Background

Thermal ablation procedures, including radiofrequency ablation (RFA) or laser-induced interstitial thermotherapy (LITT), are now well established in the treatment of malignant unresectable hepatic tumors. But the impact of partial ablation (PA) on long-term survival following computed tomography (CT)-guided radiofrequency ablation and laser- induced interstitial thermotherapy of unresectable malignant liver lesions and the associated risk factors of PA remain partially unknown.

Material/Methods

This study included 254 liver tumors in 91 consecutive patients (66 men and 25 women; age 60.9±10.4 years; mean tumor size 25±14 mm [range 5–70 mm]) who underwent thermal ablation (RFA or LITT) between January 2000 and December 2007. Mean follow-up period was 21.1 month (range 1–69 months). Survival rate and local progression-free survival (PFS) were calculated for patients with complete ablation (CA) vs. patients with partial ablation (PA) to assess the impact on long-term survival.

Results

Median survival after CA was 47 months compared to 25 months after PA (P=0.04). The corresponding 5-year survival rates were 44% vs. 20%. Median PFS for CA was 11 months compared to 7 months for PA (P=0.118). The sole statistically significant risk factor for PA was tumor size (>30 mm; P=0.0003). Sustained complete ablation was achieved in 71% of lesions ≤30 mm vs. 47% of lesions >30 mm.

Conclusions

We conclude that achievement of complete ablation is a highly important predictor of long-term survival and that tumor size is by far the most important predictor of the likelihood of achieving complete ablation.

Multi-modality treatment of colorectal liver metastases

Liver metastases synchronously or metachronously occur in approximately 50% of colorectal cancer patients. Multimodality comprehensive treatment is the best therapeutic strategy for these patients. However, the optimal pattern of multimodality therapy is still controversial, and it raises several significant concerns. Liver resection is the most important treatment for colorectal liver metastases. The definition of resectability has shifted to focus on the completion of R0 resection and normal liver function maintenance. The role of neoadjuvant and adjuvant chemotherapy still needs to be clarified. The management of either progression or complete remission during neoadjuvant chemotherapy is challenging. The optimal sequencing of surgery and chemotherapy in synchronous colorectal liver metastases patients is still unclear. Conversional chemotherapy, portal vein embolization, two-stage resection, and tumor ablation are effective approaches to improve resectability for initially unresectable patients. Several technical issues and concerns related to these methods need to be further explored. For patients with definitely unresectable liver disease, the necessity of resecting the primary tumor is still debatable, and evaluating and predicting the efficacy of targeted therapy deserve further investigation. This review discusses different patterns and important concerns of multidisciplinary treatment of colorectal liver metastases.

Radiofrequency ablation versus surgical resection for small hepatocellular carcinoma: a meta-analysis

AIM: To compare the therapeutic effects of radiofrequency ablation (RFA) and surgical hepatic resection (HR) in the treatment of small hepatocellular carcinoma (HCC).

METHODS: Literature about the controlled trials evaluating the efficacy between RFA and HR for the treatment of small HCC published between 1991 and 2011 were searched electronically. The criteria recommended by the Cochrane Handbook 4.2.2 for Systematic Reviews of Interventions were used for choosing the trails and assessing the quality of included studies. RevMan5.0.25 software was used for systematic review and meta-analysis.

RESULTS: Two randomized controlled trials and nine non-randomized controlled trials were included. A total of 2 965 patients were involved: 1 459 patients were treated with radiofrequency ablation as the initial treatment and 1 506 patients with surgical resection. Compared to the RFA group, the 3, 5-year survival rates and 1, 3, 5-year recurrence-free survival rates in the HR group was significantly higher (all P < 0.05). There were no significant difference in the 1-year survival rate between the RFA group and HR group (P > 0.05). Complications were significantly fewer in the RFA group than in the HR group (P < 0.05).

CONCLUSION: Surgical resection has more major complications than radiofrequency ablation, but the overall efficacy of surgical resection is better than radiofrequency ablation in the management of small HCC.

Radiofrequency ablation vs hepatic resection for solitary colorectal liver metastasis: A meta-analysis

AIM: To evaluate the comparative therapeutic efficacy of radiofrequency ablation (RFA) and hepatic resection (HR) for solitary colorectal liver metastases (CLM).

METHODS: A literature search was performed to identify comparative studies reporting outcomes for both RFA and HR for solitary CLM. Pooled odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using either the fixed effects model or random effects model.

RESULTS: Seven nonrandomized controlled trials studies were included in this analysis. These studies included a total of 847 patients: 273 treated with RFA and 574 treated with HR. The 5 years overall survival rates in the HR group were significantly better than those in the RFA group (OR: 0.41, 95% CI: 0.22-0.90, P = 0.008). RFA had a higher rate of local intrahepatic recurrence compared to HR (OR: 4.89, 95% CI: 1.73-13.87, P = 0.003). No differences were found between the two groups with respect to postoperative morbidity and mortality.

CONCLUSION: HR was superior to RFA in the treatment of patients with solitary CLM. However, the findings have to be carefully interpreted due to the lower level of evidence.

Radiofrequency ablation of unresectable liver tumors: factors associated with incomplete ablation or local recurrence

BACKGROUND

Radiofrequency ablation (RFA) of liver tumors is associated with a risk of incomplete ablation or local recurrence.

METHODS

One hundred sixty-eight patients with 311 unresectable liver tumors were included. Effects of different variables on incomplete ablation and local recurrence were analyzed.

RESULTS

There were 132 hepatocellular carcinomas and 179 liver metastases. Tumor size was 24 (±13) mm. Two hundred twenty-six tumors were treated percutaneously, and 85 through open approach (associated with liver resection in 42 cases). There was no mortality. Major morbidity rate was 7%. Incomplete ablation and local recurrence rates were 14% and 18.6%. Follow-up was 29 months. On multivariate analysis, factors associated with incomplete ablation were tumor size (>30 mm vs ≤30 mm, P = .004) and approach (percutaneous vs open, P = .0001). Factors associated with local recurrence were tumor size (>30 mm vs ≤30 mm, P = .02) and patient age (>65 years vs ≤65 years, P = .05).

CONCLUSIONS

RFA is effective to treat unresectable liver tumors. However, there is a risk of incomplete ablation when percutaneously treating tumors >30 mm. When tumor ablation is completely achieved, the main factor associated with local recurrence is tumor size >30 mm.

American Society of Clinical Oncology 2009 clinical evidence review on radiofrequency ablation of hepatic metastases from colorectal cancer

PURPOSE

To review the evidence about the efficacy and utility of radiofrequency ablation (RFA) for hepatic metastases from colorectal cancer (CRHM).

METHODS

The American Society of Clinical Oncology (ASCO) convened a panel to conduct and analyze a comprehensive systematic review of the RFA literature from Medline and the Cochrane Collaboration Library.

RESULTS

Because data were considered insufficient to form the basis of a practice guideline, ASCO has instead published a clinical evidence review. The evidence is from single-arm, retrospective, and prospective trials. No randomized controlled trials have been included. The following three clinical issues were considered by the panel: the efficacy of surgical hepatic resection versus RFA for resectable tumors; the utility of RFA for unresectable tumors; and RFA approaches (open, laparoscopic, or percutaneous). Evidence suggests that hepatic resection improves overall survival (OS), particularly for patients with resectable tumors without extrahepatic disease. Careful patient and tumor selection is discussed at length in the literature. RFA investigators report a wide variability in the 5-year survival rate (14% to 55%) and local tumor recurrence rate (3.6% to 60%). The reported mortality rate was low (0% to 2%), and the major complications rate was commonly reported to be between 6% and 9%. RFA is currently performed with all three approaches.

CONCLUSION

There is a compelling need for more research to determine the efficacy and utility of RFA to increase local recurrence-free, progression-free, and disease-free survival as well as OS for patients with CRHM. Clinical trials have established that hepatic resection can improve OS for patients with resectable CRHM.

Tolerance of radiofrequency ablation by patients of hepatocellular carcinoma

BACKGROUND

Radiofrequency ablation (RFA) is currently an effective method for ablation of hepatocellular carcinoma (HCC). Early reports have indicated that RFA is safe and virtually free from major complications. Unlike partial hepatectomy for HCC on patients with cirrhosis, there are no data on the safety limit of RFA. However, information is vital for selection of appropriate patients for the procedure. In this study, we analyzed results from use of RFA on HCC patients and determined the lower limit of liver function with which HCC patients can tolerate RFA.

METHOD

Preoperative variables of 310 patients who underwent RFA for HCC were analyzed to identify the risk factors in RFA intolerance in terms of morbidity associated with stress-induced complications.

RESULTS

Thirty-nine (12.6%) patients developed intolerance of RFA. Postoperative morbidity was mainly because of intractable ascites (n = 13), hyperbilirubinemia (n = 10), massive pleural effusion (n = 7), and other complications (n = 14). Multivariate analysis revealed that serum albumin level (P = 0.001), serum bilirubin level (P = 0.000), tumor number (P = 0.002), and RFA duration (P = 0.017) all played a role in this issue.

CONCLUSIONS

Simple data such as serum bilirubin, serum albumin level, and tumor number can be used to predict HCC patients' tolerance of RFA. Avoidance of excessive RFA time and careful monitoring of patients at risk are important means of reducing the postoperative morbidity rate.

Local recurrence after laparoscopic radiofrequency ablation of liver tumors: an analysis of 1032 tumors

BACKGROUND

The best measure of the technical success of radiofrequency ablation (RFA) is local recurrence (LR). The aim of this prospective study is to identify factors that predict LR.

METHODS

Three hundred thirty-five patients with 1032 unresectable liver tumors underwent laparoscopic RFA between November 1999 and August 2005. All lesions were assessed prospectively regarding tumor type, size, liver segment, blood vessel proximity, and central or peripheral location in the operating room and size of ablation zone at 1-week computed tomographic (CT) scans. Lesions that recurred in follow-up CT scans were identified prospectively. LR was categorized as contiguous or adjacent. Univariate Kaplan-Meier and Cox proportional hazard models were used for statistical analysis.

RESULTS

LR was identified 21.7% of tumors on CT scans with a mean follow-up of 17 months (median, 12 months; range, 3-68 months). This was contiguous in 70% and adjacent in 30%. LR rate per tumor was highest for colorectal metastasis (34%), followed by noncolorectal, nonneuroendocrine metastasis (22%), hepatocellular carcinoma (18%), and neuroendocrine metastasis (6%). By univariate analysis, tumor type and size, ablation margin, liver segmental location, blood vessel proximity, and type of ablation (first time vs. repeat) were found to affect LR. The Cox proportional hazard model identified tumor type, tumor size, ablation margin, and blood vessel proximity to be independent predictors of LR.

CONCLUSION

LR after RFA is predicted by certain tumor characteristics and technical factors. This information can be used intraoperatively to identify those tumors at a higher risk for failure.

Tumor response after yttrium-90 radioembolization for hepatocellular carcinoma: comparison of diffusion-weighted functional MR imaging with anatomic MR imaging

PURPOSE

Anatomic magnetic resonance (MR) imaging assessment of hepatocellular carcinoma (HCC) response to yttrium-90 ((90)Y) radioembolization may require 3 months before therapeutic effectiveness can be determined. The relationship between anatomic MR and diffusion-weighted imaging (DWI) changes after (90)Y therapy is unclear. The present study tested the hypothesis that apparent diffusion coefficient (ADC) values on DWI at 1 month precede anatomic tumor size change at 3 months after (90)Y radioembolization.

MATERIALS AND METHODS

In this prospective study, 20 patients with HCC (16 men) enrolled between April 2005 and July 2006 underwent lobar (90)Y therapy with mean doses of 141 Gy (right lobe) and 98 Gy (left lobe). Anatomic 1.5-T MR imaging (gadolinium-enhanced T1-weighted gradient-recalled echo) and DWI (single-shot spin-echo echo-planar imaging; b value of 0, 500 sec/mm(2)) were performed at baseline (0-3 weeks before (90)Y therapy) and at 1 and 3 months after (90)Y therapy. Tumor size and ADC values were measured and compared, and the percentage change in ADC was compared to the change in tumor size (minimum >5% change in size), with use of a paired t test (alpha = .05).

RESULTS

Yttrium-90 therapy was successfully delivered in all patients. The mean baseline ADC of 1.64 x 10(-3) mm(2)/sec +/- 0.30 significantly increased to 1.81 x 10(-3) mm(2)/sec +/- 0.37 at 1 month (P = .02), and to 1.82 x 10(-3) mm(2)/sec +/- 0.23 at 3 months (P = .02). The mean baseline tumor size of 83.0 cm(2) +/- 63.7 did not change statistically at 1 month (84.1 cm(2) +/- 62.1; P = .75) or 3 months (74.0 cm(2) +/- 57.0; P = .10). The overall mean ADC percentage change at 1 month of 10.5% +/- 23.1% preceded an overall mean tumor size percentage change at 3 months of -18.5% +/- 31.5% (P = .03).

CONCLUSIONS

HCC tumor response assessed with DWI at 1 month preceded anatomic size changes at 3 months after (90)Y therapy. DWI may assist in early determination of the response or failure of (90)Y therapy for HCC.

Heat-zone effect after surface application of dissecting sealer on the "in situ margin" after tumorectomy for liver tumors

BACKGROUND

Resection remains the gold standard in the treatment of liver tumors. But radiofrequency ablation allows destruction of small liver tumors. The aim of this study was to evaluate the effect of surface application of a saline-linked dissecting sealer (TL) on the tumor bed that might contain residual microscopic tumor cells after resection (in situ margin).

STUDY DESIGN

Five hepatitis-infected woodchucks bearing primary liver tumors were used. Tumors > 1 cm in diameter were removed by tumorectomy. Alternately, the in situ margins were treated or not by TL. All samples were frozen and stained with hematoxylin and eosin and nicotine adenine dinucleotide (cell viability test). The median tumor diameter was 22 mm (range 10 to 53 mm). Among 84 in situ retrieved samples, 50 were from TL-treated tumors and 34 were from untreated controls.

RESULTS

The mean (+/-SD) heat-zone area was 12.6+/-2.8 mm in TL-treated tumors and 0.6+/-0.7 mm in controls (p < 0.001). Hematoxylin and eosin and nicotine adenine dinucleotide analyses showed 70% to 98% of cell destruction inside the heat-zone area in the TL-treated samples. There were macroscopic residual tumor cells (R2 resection) in 53 samples, with a median length of tumoral tissue inside the in situ margin of 3.5 mm. Among them, the heat-zone area was considerably longer in TL-treated versus untreated controls (13.3+/-2.6 mm versus 0.7+/-0.9 mm, p < 0.001). In samples with no residual tumor cells or microscopic residual tumor cells (R0/R1; n=31), the length of the tumoral margin was similar between TL-treated and untreated controls (0.7+/-0.2 mm and 0.9+/-0.2 mm, respectively, p=NS). Compared with controls, no viable cell was visible (up to 5 mm of depth) in the in situ margins in the TL-treated samples (p < 0.05).

CONCLUSIONS

These results support the hypothesis that surface application of the TL device on the in situ margins after tumorectomy could induce a substantial heat-zone area ranging from 10 to 13 mm, inside which, on a regressive heat gradient, up to 98% of cells could be destroyed. These observations could help to reduce marginal recurrence, especially in patients requiring multiple tumorectomies or complex liver resections for malignancy.

Morbidity and mortality of laparoscopic vs. open radiofrequency ablation for hepatic malignancies

AIMS

Surgical radiofrequency ablation (RFA) of hepatic malignancies is associated with superior oncological outcome as compared to percutaneous RFA. The aim of this prospective non-randomized cohort study was to compare morbidity and mortality of laparoscopic (LRFA) vs. open (ORFA) radiofrequency ablation of liver cancer.

METHODS

Between October 1999 and November 2006, RFA was performed in 154 consecutive patients (percutaneous 12, LRFA 93, ORFA 49) for a total of 291 hepatic tumours (HCC 81, colorectal metastases 157, other 53). Seventy-four patients simultaneously underwent additional surgery. Laparoscopic RFA was performed in 45/54 patients with HCC, and in 44/54 patients with cirrhosis. Laparotomy was performed in 14/22 patients who underwent simultaneous colorectal resection, and in 12/22 patients with hepatic resection.

RESULTS

Postoperative complications occurred in 25 patients with subsequent mortality in 2. As compared with LRFA, ORFA was associated with significantly (p<0.01) higher intra-operative blood loss (median 20 (range 0-1700) vs. 10 (0-900) ml), longer duration of surgery (180 (25-440) vs. 75 (30-390) min), more postoperative complications (17 vs. 8), and longer postoperative hospital stay (8 (1-127) vs. 4 (1-51) d). According to the therapy-oriented severity grading system (TOSGS) classification, postoperative complications in the ORFA-group were more severe than those in the LRFA-group (p<0.01). These findings were consistent in patients without simultaneous colorectal and/or hepatic resection and in patients with liver tumours measuring 3cm or less. In univariate analysis the following factors were significantly (p<0.01) related to the presence of postoperative complications: simultaneous colorectal resection, laparotomy, duration of surgery, tumour location in right liver, liver segment 7 (p=0.01), absence of cirrhosis (p=0.02), liver segment 8 (p=0.03), and metastatic liver cancer (p=0.04).

CONCLUSION

LRFA for hepatic malignancies seems preferable above ORFA, provided good patient selection, surgical expertise, and long-term oncological control.