Microwave Ablation For Hepatocellular Carcinoma Research Articles

Radiofrequency ablation versus microwave ablation for hepatocellular carcinoma with cirrhosis: a propensity score analysis.

Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most frequently used percutaneous ablation techniques for the treatment of liver cancer. The aim of our study was to identify the ablation method that had a better long-term prognosis for patients with cirrhotic hepatocellular carcinoma (HCC). This retrospective study consisted of HCC patients with cirrhosis who underwent RFA and MWA between January 2014 to December 2021 at Beijing You'an Hospital. Patients were divided into two groups according to the therapeutic approaches: the RFA group and the MWA group. The prognosis was compared before and after 1:1 propensity score matching (PSM). A total of 800 HCC patients with cirrhosis who received interventional treatment from January 2014 to December 2021 were prospectively enrolled. After PSM, there were 268 patients in each of the RFA and MWA groups. The statistically significant differences in recurrence-free survival (RFS) and overall survival (OS) between RFA and MWA groups can be observed, both before and after PSM. Besides, 1-, 3-year RFS, and 5-year OS rates were higher in those the RFA group than in the MWA group. Age, tumor size, gamma glutamyl transferase (GGT), and hepatitis B surface antigen (HBsAg) were independent risk factors for RFS. Child-Pugh, lymphocyte (Lym), GGT, and treatment modality were independent risk factors for OS. For patients with HCC associated with cirrhosis, RFA can provide a better prognosis than MWA, with lower recurrence and mortality rate.

Spatial distribution pattern of local tumor progression analysis after microwave ablation of hepatocellular carcinoma based on three-dimensional magnetic resonance imaging

Objective: To investigate the spatial distribution pattern of local tumor progression (LTP) for hepatocellular carcinoma (HCC) ≤5 cm after microwave ablation. Methods: A retrospective analysis was performed on 169 HCCs with matched MRI before and after ablation from December 2009 to December 2019. A tumor MRI was reconstructed using three-dimensional visualization technology. LTP was classified as contact or non-contact, early or late stage, according to whether LTP was in contact with the edge of the ablation zone and the occurrence time (24 months). The tumor-surrounded area was divided into eight quadrants by using the eight-quadrant map method. An analysis was conducted on the spatial correlation between the quadrant where the ablative margin (AM) safety boundary was located and the quadrant where different types of LTP occurred. The t-test, or rank-sum test, was used for the measurement data. 2-test for count data was used to compare the difference between the two groups. Results: The AM quadrant had a distribution of 54.4% LTP, 64.2% early LTP stage, and 69.1% contact LTP, suggesting this quadrant was much more concentrated than the other quadrants (P < 0.001). Additionally, the AM quadrant had only 15.2% of non-contact type LTP and 17.1% of late LTP, which was not significantly different from the average distribution probability of 12.5% (100/8%) among the eight quadrants (P = 0.667, 0.743). 46.6% of early contact type LTP was located at the ablation needle tip, 25.2% at the body, and 28.1% at the caudal, while the location distribution probabilities of non-early contact LTP were 34.8%, 31.8%, and 33.3%, respectively. Conclusion: LTP mostly occurs in areas where the ablation safety boundary is the shortest. However, non-contact LTP and late LTP stages exhibit the feature of uniform distribution. Thus, this type of LPT may result from an inadequate non-ablation safety boundary.

Long-term survival analysis of ultrasound-guided percutaneous microwave ablation for hepatocellular carcinoma conforming to the Milan criteria: primary versus recurrent HCC

Background This study compared long-term outcomes between patients with initial hepatocellular carcinoma (IHCC) and those with recurrent HCC (RHCC) treated with microwave ablation (MWA). Methods This retrospective study included 425 patients with HCCs (294 IHCCs and 131 RHCCs) within the Milan criteria who were treated with ultrasound-guided percutaneous MWA between January 2008 and November 2021. All patients with RHCC had previously undergone MWA for initial HCC. Overall survival (OS) and recurrence-free survival (RFS) rates were compared between the IHCC and RHCC groups before and after propensity score matching (PSM). Results Before matching, the 1-, 3-, 5-, and 10-year OS rates in the IHCC group were 95.9%, 78.5%, 60.2%, and 42.5%, respectively, which were significantly higher than those in the RHCC group (93.8%, 70.0%, 42.0%, and 6.6%, respectively). This difference remained significant after PSM. However, subgroup analyses suggested that there were no significant differences in OS rates between IHCC and RHCC in patients with solitary HCC ≤3.0 cm, AFP ≤200 ng/mL, ablative margins ≥0.5 cm, or Albumin-Bilirubin (ALBI) grade 1. RFS was significantly higher in IHCC than in RHCC before and after PSM, as well as in subgroup analyses. ALBI grade (hazard ratio (HR), 2.38; 95% CI: 1.46–3.86; p < 0.001), serum AFP level (HR, 2.07; 95% CI: 1.19–3.62; p = 0.010) and ablative margins (HR, 0.18; 95% CI: 0.06-0.59; p = 0.005) were independent prognostic factors for OS of RHCC. Serum AFP(HR, 1.29; 95% CI: 1.02–1.63, p = 0.036) level was the only factor associated with RFS in RHCC. Conclusions MWA yielded comparable OS in IHCC and RHCC patients with solitary HCC ≤3.0 cm, AFP ≤200 ng/mL, ablative margins ≥0.5 cm, or ALBI grade 1.

Combination Therapy of Bland Transarterial Embolization and Microwave Ablation for Hepatocellular Carcinoma within the Milan Criteria Leads to Significantly Higher Overall Survival.

A comparison of the combination therapy consisting of microwave ablation (MWA) after bland lipiodol-based transarterial embolization (TAE) with MWA alone in the treatment of hepatocellular carcinoma (HCC) within the Milan criteria. Forty-nine patients in the TAE-MWA group (12 women and 37 men; mean age: 63.3 ± 9.6 years) with 55 tumors and 63 patients in the MWA group (18 women and 45 men; mean age: 65.9 ± 10.5 years) with 67 tumors were retrospectively enrolled in this study. For the investigation of treatment protocols based upon both safety and efficacy, patients' cases were analyzed with regard to complications, local tumor progression (LTP), intrahepatic distant recurrence (IDR), overall survival (OS), and progression-free survival (PFS). There were no cases of major complications in either group. The LTP rate was 5.5% in the MWA-TAE group and 7.5% in the MWA group (p = 0.73). The rate of IDR was 42.9% in the MWA-TAE group and 52.4% in the MWA group (p = 0.42). The 12-, 24-, and 36-month OS rates starting at the date of tumor diagnosis were 97.7%, 85.1%, and 78.8% in the TAE-MWA group, and 91.9%, 71.4%, and 59.8% in the MWA group, respectively (p = 0.004). The 6-, 12-, and 24-month PFS rates were 76.5%, 55%, and 44.6% in the TAE-MWA group, and 74.6%, 49.2%, and 29.6% in the MWA group, respectively (p = 0.18). The combination therapy of TAE-MWA was significantly superior to MWA monotherapy according to OS in treating HCC within the Milan criteria.

Local anaesthesia vs. general anaesthesia for percutaneous microwave ablation in hepatocellular carcinoma: efficacy, safety, and cost analysis.

To compare the efficacy, safety, and cost of local anaesthesia and general anaesthesia modalities for percutaneous microwave ablation as a curative treatment for hepatocellular carcinoma patients. This comparative, retrospective study analysed 175 patients who were treated for hepatocellular carcinoma (HCC) from July 2015 to September 2020. Conventional transcatheter arterial chemoembolization (cTACE) combined with sequential percutaneous microwave ablation (MWA) was performed on every lesion in every patient. Patients were divided into two cohorts according to the anaesthesia modality applied during MWA. To investigate the differences in efficacy between the two groups, overall survival (OS) and local recurrence-free survival (LRFS) were estimated by the Kaplan-Meier method and compared by the log-rank test. Cost and safety between the two groups were also compared accordingly. There were 105 patients with 128 HCC lesions in the local anaesthesia (LA) group and 70 patients with 107 lesions in the general anaesthesia (GA) group. There were no significant differences in OS (P = 0.798) or LRFS (P = 0.406) between the two groups. Fifty-two pairs of patients were matched with 77 lesions in the GA group and 67 lesions in the LA group after PSM. There was no significant difference in OS (P = 0.522) or LRFS (P = 0.410) between the two groups. Compared to the LA group, the GA group had longer operations, consumed more medical resources, had a heavier financial burden, and experienced more anaesthesia adverse events. There was no significant difference in the incidence of post-ablation pain (p=0.487), fever (P=0.678), nausea or vomiting (P=0.808), mild liver dysfunction (P=0.753), haemolytic uraemic syndrome (P=0.595), pleural effusion (P=0.622), liver abscess (0.544), asymptomatic perihepatic fluid (0.703) or subcapsular liver hemorrhage (P=0.666) between the two groups. Due to the higher cost and adverse events of general anaesthesia, local anaesthesia may be more suitable for ablation procedures for HCC patients within the Milan criteria.

Double closed loop small bowel obstruction due to right diaphragmatic hernia after transcatheter arterial chemoembolization and microwave ablation for hepatocellular carcinoma.

64-Year-old male patient with hepatocellular carcinoma (HCC), liver cirrhosis, chronic hepatitis C infection, and glottic cancer presented with acute progressive abdominal pain and palpable mass in right upper quadrant of the abdomen. Despite treatment with hyoscine and tramadol, the symptoms persisted. He had received three sessions of Transcatheter arterial chemoembolization (TACE) and two sessions of microwave ablation (MWA) for HCC treatment, with the last session being TACE 11months prior. Plain film abdomen showed bowel gas pattern in the right hemithorax compatible with bowel obstruction. CT imaging revealed a right diaphragmatic hernia containing closed loop small bowel obstruction. An emergency exploratory laparotomy was performed. The patient improved and was discharged. There was no recurrence of diaphragmatic hernia or abdominal mass or pain at the 6-month follow-up visit. We herein demonstrate a catastrophic complication of TACE by using an IPA and MWA which leads to right diaphragmatic hernia.

Percutaneous Microwave Ablation of Hepatocellular Carcinoma with "Double Fusion" Technique: Technical Note and Single-Center Preliminary Experience.

Percutaneous image-guided thermal ablation is included in most society guidelines for treatment of hepatocellular carcinoma (HCC). The results of this treatment in terms of efficacy depend on the ability to precisely place the device into the target tumor. Ultrasound (US) is a commonly used imaging guidance modality for its real-time feedback. However, an accurate device deployment remains challenging in some clinical scenarios, including cases of tumors that are undetectable or not clearly visible by US. To overcome this problem, fusion imaging techniques have been developed, which combine images from different modalities. The most widely known technique combines pre-procedural contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) with real-time US scans. Cone beam CT (CBCT) is a technology that can provide intra-procedural cross-sectional images, which can be registered to images from other modalities, including preprocedural CT/MR scans. The aim of our study is to report the preliminary experience on percutaneous microwave ablation (MWA) of patients with HCC that were treated using the "double fusion" technique, which combines the use of US fusion imaging and CBCT fusion imaging. We describe the technical details, feasibility, safety and short-term efficacy of this technique in a small series of eight patients with 11 HCCs.

Initial experience of microwave ablation for hepatocellular carcinoma using Mimapro™

Initial experience of microwave ablation for hepatocellular carcinoma using Mimapro™

Gastric Perforation After Microwave Ablation to Adjacent Hepatocellular Lesion

ABSTRACT Locoregional treatment modalities for hepatocellular carcinoma are generally effective and safe and benefit the subset of patients who are not eligible for surgery or have marginal hepatic function. This case report discusses a 77-year-old patient with cirrhosis who underwent microwave lesion ablation for 3 hepatocellular carcinoma nodules. On the 12th day after ablation, the patient was diagnosed with a perforation of the anterior wall of the stomach near one of the target ablation sites on the left side of the liver. The patient underwent surgical therapy with clinical improvement. This report highlights the potential risks associated with microwave ablation for hepatocellular carcinoma.

Clinical Results, Risk Factors, and Future Directions of Ultrasound-Guided Percutaneous Microwave Ablation for Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide, with a relatively poor prognosis, especially for advanced HCC. With the availability of a variety of treatment options, the treatment strategies for HCC have become more and more diversified. Microwave ablation (MWA) has gradually been considered as a viable alternative to surgical resection (SR) owing to its comparable long-term survival, reduced complications, and greater preservation of hepatic parenchyma. However, clinical outcomes, tumor progression, and recurrence of HCC after MWA remain major concerns. Here, after reviewing the current therapeutic options for HCC, we focus on MWA, describing the advantages and challenges of MWA and the clinical results after treatment. We then focused on prognostic factors that influence post-ablation clinical outcomes and briefly presented the strategy of MWA for future clinical treatment.

Different power modes of microwave ablation for hepatocellular carcinoma: Evaluation of recurrence rate and factors related to recurrence

PurposeTo evaluate the safety and efficacy of different power modes(constant power and variable power) percutaneous microwave ablation (MWA) for treating hepatocellular carcinoma (HCC) and to predict the risk factors of recurrence after MWA. Materials and methodsIn this retrospective study, a total of 112 patients with solitary HCC were included from January 2015 to January 2021. All patients received MWA through a percutaneous approach that was guided by ultrasound, 45 patients received variable power MWA, and the remaining 67 were treated with constant power MWA. The complete ablation rates, local recurrence rates, complications, and short-term survival were analyzed. Possible risk factors for tumor recurrence were analyzed. ResultsThe complete ablation rates were 95.9% for the first ablation and 100% for the second ablation for ≤3 cm lesions. The complete ablation rates were 84.2%(95.9% versus 84.2%, p = 0.039) for the first ablation and 94.7% (100% versus 94.7%, p = 0.113) for the second ablation for 3–5 cm lesions. Local and distant recurrence rates were 18.7%(21/112) and 14.3%(16/112). The 1-, 2-year survival rates were 86.3 and 66.3%, respectively. Subgroup analysis showed that 1-, 2-year survival rates were 91.1% and 78.5% in ≤3 cm group, and were 74.4% and 40.9% in 3–5 cm group, respectively. Univariate analysis revealed that a positive correlation existed between the HBV DNA replication(p = 0.007), AFP level of pre-MWA(p = 0.001) and post-MWA(p<0.001), tumor diameter(p<0.001), irregular shape(p = 0.014), proximity to the risk location(p = 0.008), poor differentiation(p = 0.003), constant power(p = 0.028), length(p<0.001) and width of ablation zone(p = 0.001), and present complication(p<0.001), and early recurrence. Multivariate analysis identified HBV DNA replication(OR = 0.266, p = 0.036), AFP level of pre-MWA (OR = 4.001, p = 0.036), tumor diameter (OR = 2.153, p = 0.042), tumor location (OR = 0.910, p = 0.046), and width of ablation zone(OR = 2.530, p = 0.044) were independent prognosis factors causing postoperative HCC recurrence. ConclusionVariable power MWA of HCC appears to be a safe and effective treatment. HBV DNA, AFP level of pre-MWA, tumor diameter, tumor location, and width of ablation range appear to be independent predictors of tumor recurrence.

Patient Selection and Outcomes of Laparoscopic Microwave Ablation of Hepatocellular Carcinoma.

Laparoscopic microwave ablation (MWA) of hepatocellular carcinoma is underutilized and predictors of survival in this setting are not well characterized. The prognostic value of clinicopathologic variables was evaluated on progression-free survival (PFS) and overall survival (OS) by univariate and multivariate analyses. The aim of this study was to evaluate a preferred laparoscopic MWA approach in HCC patients that are not candidates for percutaneous ablation and further classify clinicopathologic factors that may predict survival outcomes following operative MWA in the setting of primary HCC. 184 patients with HCC (median age 66, (33-86), 70% male) underwent laparoscopic MWA (N = 162, 88% laparoscopic) compared to 12% undergoing open MWA (N = 22). Median PFS was 29.3 months (0.2-170) and OS was 44.2 months (2.8-170). Ablation success was confirmed in 100% of patients. Ablation recurrence occurred in 3% (6/184), and local/hepatic recurrence occurred in 34%, at a median time of 19 months (9-18). Distant progression was noted in 8%. Median follow up was 34.1 months (6.4-170). Procedure-related complications were recorded in six (9%) patients with one 90-day mortality. Further, >1 lesion, AFP levels ≥ 80 ng/mL, and an "invader" on pre-operative radiology were associated with increased risk of progression (>1 lesion HR 2.92, 95% CI 1.06 -7.99, p = 0.04, AFP ≥ 80 ng/mL HR 4.16, 95% CI 1.71-10.15, p = 0.002, Invader HR 3.16, 95% CI 1.91-9.15, p = 0.002 ) and mortality (>1 lesion HR 3.62, 95% CI 1.21-10.81, p = 0.02], AFP ≥ 80 ng/mL HR 2.87, 95% CI 1.12-7.35, p = 0.01, Invader HR 3.32, 95% CI 1.21-9.81, p = 0.02). Preoperative lesion number, AFP ≥ 80 ng/mL, and an aggressive imaging characteristic (Invader) independently predict PFS and OS following laparoscopic operative MWA.

Anti-PD-L1 antibody enhances curative effect of cryoablation via antibody-dependent cell-mediated cytotoxicity mediating PD-L1highCD11b+ cells elimination in hepatocellular carcinoma.

Cryoablation (CRA) and microwave ablation (MWA) are two main local treatments for hepatocellular carcinoma (HCC). However, which one is more curative and suitable for combining with immunotherapy is still controversial. Herein, CRA induced higher tumoral PD-L1 expression and more T cells infiltration, but less PD-L1highCD11b+ myeloid cells infiltration than MWA in HCC. Furthermore, CRA had better curative effect than MWA for anti-PD-L1 combination therapy in mouse models. Mechanistically, anti-PD-L1 antibody facilitated infiltration of CD8+ T cells by enhancing the secretion of CXCL9 from cDC1 cells after CRA therapy. On the other hand, anti-PD-L1 antibody promoted the infiltration of NK cells to eliminate PD-L1highCD11b+ myeloid cells by antibody-dependent cell-mediated cytotoxicity (ADCC) effect after CRA therapy. Both aspects relieved the immunosuppressive microenvironment after CRA therapy. Notably, the wild-type PD-L1 Avelumab (Bavencio), compared to the mutant PD-L1 atezolizumab (Tecentriq), was better at inducing the ADCC effect to target PD-L1highCD11b+ myeloid cells. Collectively, our study uncovered the novel insights that CRA showed superior curative effect than MWA in combining with anti-PD-L1 antibody by strengthening CTL/NK cell immune responses, which provided a strong rationale for combining CRA and PD-L1 blockade in the clinical treatment for HCC.

Stereotactic Microwave Ablation of Hepatocellular Carcinoma: The Impact of Tumor Size and Minimal Ablative Margin on Therapeutic Success

Microwave ablation (MWA) has gained relevance in the treatment of hepatic malignancies and especially in hepatocellular carcinoma (HCC), and it is an important alternative to surgery. The purpose of the study was to evaluate whether the minimal ablative margin (MAM) or the initial tumor size has a greater effect on the success of stereotactic MWA of HCC regarding the time to local tumor progression (LTP) and overall survival (OS). 88 patients, who received stereotactic MWA of 127 tumor lesions with a curative intention were included in this single-center, retrospective study. The MAM was evaluated in a side-by-side comparison of pre- and post-ablative, contrast-enhanced slice imaging. A Cox proportional hazard model with a frailty term was computed to assess the influence of the MAM and the maximum tumor diameter on the time to LTP and the OS. The maximum tumor diameter was identified as a significant positive predictor for LTP (hazard ratio 1.04, 95% CI 1.00-1.08, p = 0.03), but it was not a significant positive predictor for the OS (p = 0.20). The MAM did not have a significant influence on LTP-free survival (p = 0.23) and OS (p = 0.67). For the successful stereotactic MWA of HCC, the MAM and maximum tumor diameter might not have an influence on the OS, but the maximum tumor diameter seems to be an independent predictor of the time to LTP.

The tumor ghost on MRI after microwave ablation for hepatocellular carcinoma: A new modality to assess the ablative margin

PurposeThe ablated tumor ghost can be visually distinguished on MR images after ablation. This retrospective study aimed to assess the performance of tumor ghost on post-ablation contrast-enhanced MRI with excellular contrast agent gadolinium-DTPA in evaluating the ablative margin of hepatocellular carcinoma (HCC) after microwave ablation (MWA). Method315 HCC lesions less than 5 cm in 287 patients completely treated by MWA were enrolled in the study. The tumor ghost was characterized as a lower signal intensity area than the surrounding tissues of the ablation zone on T1WI imaging. The ablation margin (AM) status was classified into AM0 (＞5mm) and AM1 (＜5mm) according to the minimum distance between the tumor ghost and ablated zone. Inter-observer agreement between two radiologists on the AM assessment was analyzed using the Cohen κ coefficient. Multivariate analysis using Cox proportional hazard model was performed to investigate independent risk factors for LTP. Results175 and 140 tumors were evaluated as AM0 and AM1 through tumor ghost. The inter-observer agreement level between two radiologists for assessment of AM was good (κ coefficient = 0.752, 95 % confidence interval: 0.679–0.825, p < 0.001). The mediate follow-up period was 32.2 months (range 3.0–60.8 months). The incidence of LTP in the AM0 lesions and AM1 lesions was 6.3 % (11/175) and 20.0 % (28/140), respectively. AM status was identified as an independent prognostic factor for LTP (HR 3.057, 95 % CI, 1.445–6.470, p = 0.003). ConclusionsThe assessment of the AM by tumor ghost on post-ablation MRI is an accurate and efficiently method for evaluating the completeness of microwave ablation for hepatocellular carcinoma.

Liver resection versus microwave ablation for hepatocellular carcinoma in ideal candidates for ablation per Barcelona Clinic Liver Cancer staging: a propensity score matching and inverse probability of treatment weighting analysis.

Liver resection (LRE) and microwave ablation (MWA) for hepatocellular carcinoma (HCC) have been widely compared. To compare the therapeutic outcomes of percutaneous MWA and LRE for HCC in ideal candidates for ablation according to Barcelona Clinic Liver Cancer (BCLC) staging METHODS: Between August 2013 and November 2020, 483 consecutive patients meeting criteria for "ideal candidates for ablation" per the BCLC staging initially treated with MWA (n=168) or LRE (n=315) were included. Patients were further divided into BCLC-0 (n=116) and BCLC-A (n=367) groups. Overall survival (OS), recurrence-free survival (RFS) and post-procedure-related complication rates were compared before and after propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) in the overall population and subgroups. Multivariate Cox regression analysis was performed to determine whether the treatment modality was an independent prognostic factor. LRE had a better RFS and similar OS and post-procedure-related complication rates compared to MWA in the overall population and in the BCLC-A subgroup both before and after PSM and IPTW. However, the OS, RFS and post-procedure-related complication rates were equivalent between the two groups before and after PSM and IPTW in patients with BCLC-0 disease. The multivariate Cox regression analysis showed that LRE was associated with better RFS over MWA in overall population (p=0.003; HR=0.67; 95% CI: 0.51-0.87) and BCLC-A disease (p=0.046; HR=0.74; 95% CI: 0.56-0.99), while it did not differ in OS. An 'ideal candidate for ablation' according to the BCLC staging system may not be an ideal candidate for MWA. However, patients with BCLC-0 may be the optimal population for MWA.

Cone beam computed tomography-guided microwave ablation for hepatocellular carcinoma under the hepatic dome: a retrospective case-control study.

BackgroundMicrowave ablation (MWA) for hepatocellular carcinoma (HCC) under the hepatic dome is still clinically challenging. This retrospective control study set out to analyze the technical application and clinical benefits of cone beam computed tomography (CBCT)-guided MWA for HCC under the hepatic dome.MethodsThe study analyzed 76 patients with 110 HCC lesions under the hepatic dome from April 2016 to January 2020. The patients were divided into two groups: (I) the CBCT group (n=31), in which iGuide navigation was used for the puncture, and (II) the conventional computed tomography (cCT) group (n=45), in which a navigation tool was not used for the puncture. The primary endpoints were technical success, puncture score, and the rates of complete ablation (CA), complications, and local tumor progression (LTP). The secondary endpoints were tumor-free survival (TFS) and overall survival (OS).ResultsIn terms of the primary endpoints, the puncture score, occurrence of pleural effusion, and occurrence of right shoulder pain differed significantly between the CBCT group and the cCT group (2.8 vs. 2.2, P=0.002; 12.9% vs. 35.6%, P=0.03; 9.7% vs. 33.3%, P=0.03, respectively). However, the rates of technical success, CA, major complications, and LTP showed no significant differences between the two groups (100% vs. 100%, P>0.009; 0% vs. 0%, P>0.009; 95.6% vs. 89.2%, P=0.30; 4.5% vs. 4.6%, P=0.96, respectively). Regarding the secondary endpoints, the median TFS was 23.0 [95% confidence interval (CI): 19.5–26.5] vs. 22.0 (95% CI: 18.4–25.6) months (P=0.41) and the median OS was 31.0 (95% CI: 21.4–40.6) vs. 33.0 (95% CI: 27.9–38.2) months (P=0.95).ConclusionsCone beam CT is a feasible and effective image guidance tool for MWA of HCC under the hepatic dome.

S367 Endoscopic Eversion and Stent-Assisted Strangulation for the Management of an Intraductal Papillary Neoplasm of the Bile Duct: A Minimally Invasive Technique for Non-Surgical Candidates

Introduction: Intraductal papillary neoplasms of the bile duct (IPNB) are uncommon lesions that may accompany risk for malignancy. Management is often surgical and may be associated with significant postoperative morbidity and mortality. Case Description/Methods: An 80-year-old female with a history of hepatocellular carcinoma (HCC) presented for management of jaundice and sepsis after microwave ablation of HCC. Computed tomography (CT) imaging demonstrated intra and extrahepatic biliary ductal dilation with a 19 mm soft tissue density in the distal common bile duct (CBD). Index labs depicted leukocytosis, hyperbilirubinemia, and elevated lactate. Endoscopic ultrasound (EUS) delineated a round, hypoechoic intraductal CBD lesion. The pancreas and ampulla were normal. Endoscopic retrograde cholangiopancreatography (ERCP) confirmed a distal CBD filling defect. Biliary sphincterotomy was performed and balloon sweeping revealed a frond-like partially protruding polypoid lesion suggestive of an IPNB. Due to non-surgical candidacy, we decided to perform a complete eversion with subsequent full prolapse of the lesion by using a biliary extraction balloon. This was followed by the placement of a biliary plastic stent to assist with strangulation of the base of the lesion. Biopsies were consistent with a papillary neoplasm with intestinal differentiation, confirming our findings of an IPNB, without accompanying high-grade dysplasia or carcinoma. Interval surveillance ERCP 3 months later revealed no protruding lesion from the major papilla, no residual filling defects on cholangiogram, and sweeping of the biliary tree uncovered no contents. Cholangioscopy demonstrated segmental mucosal irregularity with mild granular tissue in the mid/distal bile duct wall; however, cholangioscopy-guided intraductal biopsies and brushings showed benign reactive tissue and no recurrent IPNB. At 5 months of follow-up, the patient continues to do well. Discussion: IPNB is a rare biliary lesion. Radical surgical resection has been the mainstay of curative treatment. However, a few recent cases have described endoluminal radiofrequency ablation as an alternative therapy. To the best of our knowledge, this is the first reported case of balloon-assisted eversion combined with stent-assisted strangulation of an IPNB leading to spontaneous removal. In non-surgical candidates, this technique may be advantageous to minimize adverse operative outcomes, improve patient tolerance, and decrease cost. Watch the video at https://tinyurl.com/ACGAbstractS367

Retrospective Evaluation and Significance of Neutrophil-to-Lymphocyte Ratio Prior to and 1 month Following Microwave Ablation of Hepatocellular Carcinoma.

Neutrophil-to-lymphocyte ratio (NLR) recently demonstrated predictive value for hepatocellular carcinoma (HCC) recurrence after thermal ablation. Microwave ablation (MWA) has been shown to induce changes in the immune landscape after HCC treatment. This study aims at identifying predictors of local tumor progression (LTP) and post-treatment NLR kinetics after MWA. Data from 108 consecutive patients who underwent percutaneous MWA of 119 HCCs with a 2450Hz/100W generator in two institutions from October 2014 to September 2021 were retrospectively reviewed. Forty-five HCCs (42 patients) met inclusion criteria for analysis (technique efficacy, pre- and post-treatment NLR availability, follow-up > 6months, absence of complications). NLR was analyzed prior to therapy and at 1-month follow-up; difference between the two time points was defined as ΔNLR1stFU. After a median follow-up of 25months, LTP occurred in 18 HCCs (40%) and 18 patients (42.9%). Multivariate competing risk regression comprising ΔNLR1stFU > 0, cirrhosis etiology and subcapsular location showed that the only independent predictor of LTP was ΔNLR1stFU > 0, on both a per-patient (HR = 2.7, p = 0.049) and per-tumor (HR = 2.8, p = 0.047) analysis. ΔNLR1stFU > 0 occurred in 24/42 patients (57.1%). In this subgroup, higher rates of female patients (p = 0.026), higher mean baseline NLR (p < 0.0001) and lower mean energy/size (p = 0.006) were observed. Upon ROC curve analysis, energy/size < 1414J/mm predicted ΔNLR1stFU > 0 with 76% sensitivity and 70% specificity (AUC = 0.74). NLR increase after ablation was the only independent predictor of LTP, supporting the role of balance between systemic inflammation and immunity in recurrence after MWA. Ablation energy/tumor size predicted NLR increase, reinforcing the concept of immune ablation. III.

A Machine Learning Model Based on Health Records for Predicting Recurrence After Microwave Ablation of Hepatocellular Carcinoma.

Background and AimEarly recurrence (ER) presents a challenge for the survival prognosis of patients with hepatocellular carcinoma (HCC). The aim of this study was to investigate machine learning (ML) models using clinical data for predicting ER after microwave ablation (MWA).MethodsBetween August 2005 and December 2019, 1574 patients with early-stage HCC underwent MWA at four hospitals were reviewed. Then, 36 clinical data points per patient were collected, and the patients were assigned to the training, internal, and external validation set. Apart from traditional logistic regression (LR), three ML models—random forest, support vector machine, and eXtreme Gradient Boosting (XGBoost)—were built and validated for their predictive ability with the area under ROC curve (AUC). Algorithms such as SHapley Additive exPlanations (SHAP) and local interpretable model-agnostic explanations (LIME) were used to realize their interpretability.ResultsThe three ML models all outperformed LR (P < 0.001 for all) in predictive ability. When nine variables (tumor number, platelet, α-fetoprotein, comorbidity score, white blood cell, cholinesterase, prothrombin time, neutrophils, and etiology) were extracted simultaneously using recursive feature elimination with cross-validation, the XGBoost model achieved the best discrimination among all models, with an AUC value 0.75 (95% CI [confidence interval]: 0.72–0.78) in the training set, 0.74 (95% CI: 0.69–0.80) in the internal validation set, and 0.76 (95% CI: 0.70–0.82) in the external validation set, and it was interpreted depending on the visualization of risk factors by the SHAP and LIME algorithms. The predictive system of post-ablation recurrence risk stratification was provided on online (http://114.251.235.51:8001/) based on XGboost analysis.ConclusionThe XGBoost model based on clinical data can effectively predict ER risk after MWA, which can contribute to surveillance, prevention, and treatment strategies for HCC.