Ablation protocols and ancillary procedures in tumor ablation therapy: consensus from Japanese experts

Is cryoablation a valid option for renal cell carcinomas in direct contact with critical organs?

PURPOSE

This study aimed to assess the outcomes of percutaneous cryoablation (PCA) for renal cell carcinomas (RCCs) contacting critical organs without intervening fat tissue.

MATERIAL AND METHODS

Twenty-three patients with 24 RCCs (mean size, 28.8 mm) contacting critical organs on preprocedural images were included. The organ displacement techniques, technical success, efficacy, and adverse events per Clavien-Dindo classification were retrospectively reviewed.

RESULTS

The organs contacting the RCCs included the colon (n = 16), pancreas (n = 3), duodenum (n = 3), small intestine (n = 1), and stomach (n = 1). In all procedures, hydrodissection was conducted, and probe traction was additionally utilized in one to displace organs. Two procedures were terminated with an insufficient ice-ball margin (<6 mm) due to recurring proximity of the colon or thermal sink effect by renal hilar vessels, yielding a technical success rate of 91.6% (22/24). No severe adverse events were noted. All patients were alive without any metastases during a median follow-up of 34.4 months. The primary and secondary technical efficacy rates were 91.6% (22/24) and 95.8% (23/24) of tumors, respectively.

CONCLUSION

PCA can be a valid option for RCCs contacting critical organs with a good safety profile and sufficient technical efficacy.

Renal cryoablation combined with prior transcatheter arterial embolization in non-dialysis patients with stage 4 or 5 chronic kidney disease: a retrospective study

PURPOSE

To retrospectively evaluate cryoablation combined with prior transcatheter arterial embolization (TAE) for renal cell carcinoma (RCC) in non-dialysis patients with stage 4 or 5 chronic kidney disease (CKD).

MATERIALS AND METHODS

Patients with stage 4 or 5 CKD undergoing TAE and cryoablation for RCC between May 2012 and October 2021 were included. TAE was selectively performed using iodized oil with absolute ethanol or gelatin sponge 1-14 days before cryoablation. Local efficacy, safety, and changes in renal function were evaluated.

RESULTS

Nine patients (seven men and two women; median age, 64 years; range 52-88 years) with nine RCCs (mean diameter, 3.0 ± 1.0 cm; range 1.7-4.7 cm) were included. The mean pre-treatment estimated glomerular filtration rate (eGFR) was 24.2 ± 5.6 ml/min/1.73 m2 (range 10.4-29.2 ml/min/1.73 m2). The mean amount of contrast medium used in TAE was 58 ± 29 ml (range 40-128 ml). Except in one patient (grade 3 pyelonephritis), no grade ≥ 3 complications occurred. During the follow-up period (median, 18 months; range 7-54 months), no local tumor progression occurred. In two patients with pre-treatment eGFR of < 20 ml/min/1.73 m2, hemodialysis was initiated at 3 and 19 months after cryoablation. At their last follow-up, the remaining seven patients showed a decrease of 6.2 ± 5.3 ml/min/1.73 m2 (range 0.7-17.2 ml/min/1.73 m2) in their eGFR.

CONCLUSION

Cryoablation combined with TAE for RCC in non-dialysis patients with stage 4 or 5 CKD was effective and safe, with an acceptable impact on renal function.

Transarterial ethiodised oil marking before CT-guided renal cryoablation: evaluation of tumour visibility in various renal cell carcinoma subtypes

AIM

To evaluate ethiodised oil retention of transarterial embolisation using ethiodised oil (ethiodised oil marking) before computed tomography (CT)-guided percutaneous cryoablation (PCA) according to renal cell carcinoma (RCC) subtype.

MATERIALS AND METHODS

Ethiodised oil marking was performed 1-3 days before PCA in 99 patients with 99 RCCs from 2016 to 2020. Ethiodised oil retention on CT images was evaluated retrospectively and CT attenuation values in the tumour were measured. Regions of interest (ROI) were placed on the tumours to calculate: average (ROI-average), maximal (ROI-max), minimum (ROI-min), and standard deviation (ROI-SD). Qualitative scores comprising a five-point scale (5, excellent; 1, poor) were evaluated for the retention scores (RS) of ethiodised oil in the tumour (ethiodised oil-RS) and the visualisation scores (VS) of the boundary between the tumour and renal parenchyma (boundary-VS).

RESULTS

The histological subtypes comprised clear cell (ccRCC; n=85), papillary (pRCC; n=6), and chromophobe/oncocytoma renal cell carcinoma (chrRCC; n=8). The mean ROI-average, ROI-max, and ROI-SD were significantly higher in ccRCCs than in chrRCCs and pRCCs (p<0.05). The mean ethiodised oil-RS was significantly lower in pRCCs than in ccRCCs (p=0.039), and the mean boundary-VS was >4 in all subtypes. Even with poor intratumour ethiodised oil retention (n=6), sufficient boundary-VS was obtained due to "inverted marking." All PCA procedures were completed without additional intravenous contrast material injection at the time of PCA.

CONCLUSION

Regardless of the tumour subtypes, ethiodised oil marking aids in visualising the boundary between the tumour and parenchyma on non-contrast CT in PCA.

CT evaluation of patent artery after percutaneous cryoablation of renal cell carcinoma

PURPOSE

The purpose of this retrospective study was to determine the incidence of persistent patent artery after percutaneous cryoablation of renal cell carcinoma (RCC) and the relationship between patent arteries one month after cryoablation and early tumor progression.

MATERIALS AND METHODS

One hundred and fifty-nine patients (112 men, 47 women; mean age, 63.6±14.6 [SD] years; age range: 21-91 years) who underwent percutaneous cryoablation for 186 RCCs (mean diameter, 1.9±0.6 [SD] cm; range: 0.7-4.0cm) were retrospectively included. After cryoablation, patients underwent contrast-enhanced computed tomography (CT) with ≤2-mm slice thickness within one week from cryoablation, and at one, three, and six months. The time course of patent artery in the ablated renal parenchyma after cryoablation was the primary endpoint. The relationships between patent arteries one month after cryoablation and treatment effectiveness, tumor vascularity, tumor enhancement one month after cryoablation, tumor subtype, and renal function changes were evaluated as secondary endpoints.

RESULTS

CT showed patent arteries in the ablated renal parenchyma within one week in 166 RCCs (89.2%), at one month in 54 RCCs (29.0%), at three months in 8 RCCs (4.3%), and at six months in 2 RCCs (1.1%). The presence of patent artery one month after cryoablation was significantly associated with tumor enhancement at the same time point (P=0.015). There was no association between patent arteries one month after cryoablation and treatment effectiveness (P=0.693).

CONCLUSION

Patent arteries in the ablated renal parenchyma are commonly observed on CT examination after percutaneous cryoablation of RCC. However, they gradually disappear and do not require specific treatment.

Asian Conference on Tumor Ablation Guidelines for Adrenal Tumor Ablation

Thermal ablation is a good alternative treatment in patients who are unable to undergo adrenalectomy. Even though the Asian Conference on Tumor Ablation (ACTA) has been held for many years, adrenal ablation guidelines have not been established. No guidelines for adrenal ablation are established in American and European countries, either. The aim of this review was to introduce the first version of ACTA guidelines for adrenal tumor ablation.

Asian Conference on Tumor Ablation guidelines for renal cell carcinoma

Thermal ablation has been established as an alternative treatment for renal cell carcinoma (RCC) in patients who are poor candidates for surgery. However, while American and European guidelines have been established for American and European patients, respectively, no ablation guidelines for Asian patients with RCCs have been established many years after the Asian Conference on Tumor Ablation (ACTA) had been held. Given that Western guidelines are difficult to apply to Asian patients due to differences in body habitus, economic status, and insurance systems, the current review sought to establish the first version of the ACTA guidelines for treating a RCC with thermal ablation.

Evaluation of Temperature Distribution Around the Probe in Cryoablation of Lipiodol-Mixed-Tissue Phantom

PURPOSE

To determine whether lipiodol, which has low thermal conductivity, influences ice ball formation during cryoablation of a lipiodol-mixed-tissue phantom.

MATERIALS AND METHODS

Lipiodol-mixed-tissue phantoms were created by injecting lipiodol (4-6 ml) into the renal arteries of ex vivo porcine kidneys (lipiodol group). A cryoprobe (CryoHit^™ Needle S) with a holder that was set with thermocouples at various positions around the cryoprobe was inserted. After freezing for 300 s, the followings were evaluated: ice ball size on CT, temperature distribution around the cryoprobe, and calculated distances at 0 °C and - 20 °C. Each variable was compared between lipiodol group (n = 6) those obtained in a control group without lipiodol injection (n = 6).

RESULTS

Mean ice ball diameter (width/length) on CT was 22.1 ± 2.3/22.9 ± 2.3 mm in the lipiodol group and 21.6 ± 0.7/22.2 ± 1.3 mm in the control group. Mean cryoprobe temperature was - 118 ± 3.0 °C in the lipiodol group and - 117 ± 2.6 °C in the control group. In both groups, temperature at the 3 mm thermocouple reached approximately - 50 °C and was < 0 °C within ~ 10 mm of the cryoprobe. Temperature of 0/- 20 °C occurred at a mean distance from the cryoprobe of 11.1 ± 0.5/6.9 ± 0.4 mm in the lipiodol group and 11.0 ± 0.2/6.9 ± 0.2 mm in the control group. There was no significant difference in any variable between the groups.

CONCLUSION

The inclusion of lipiodol in a tissue phantom had no negative effects on ice ball formation that were related to thermal conductivity.

Combination therapy by transarterial injection of miriplatin-iodized oil suspension with radiofrequency ablation (RFA) versus microwave ablation (MWA) for small hepatocellular carcinoma: a comparison of therapeutic efficacy

PURPOSE

To compare the technical efficacy and complications of the transarterial injection of a miriplatin-iodized oil suspension combined with radiofrequency ablation (RFA) or microwave ablation (MWA) in the treatment of small hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

This retrospective study included 123 HCCs in 101 patients treated with the transarterial injection of a miriplatin-iodized oil suspension and RFA (MPT-RFA) (maximum diameter: 1.5 [Formula: see text] 0.5 cm, range: 0.6-3.0 cm) and 68 HCCs in 49 patients treated with the transarterial injection of a miriplatin-iodized oil suspension and MWA (MPT-MWA) (maximum diameter: 1.6 [Formula: see text] 0.7 cm, range: 0.5-3.0 cm). Technical success was defined as the achievement of an ablative margin of at least 5 mm for each tumor. Technical success, complications, and local tumor progression were compared between the two groups.

RESULTS

The initial technical success rate was significantly higher with MPT-MWA (94.1%) than with MPT-RFA (76.4%; P = 0.003). The number of treatment sessions per nodule was significantly lower with MPT-MWA (1.1) than with MPT-RFA (1.3) (P = 0.004). The major complication rates were similar with MPT-RFA (5.8%) and MPT-MWA (2.7%) (P = 0.391). The one-year local tumor progression rate was similar between MPT-RFA (0%) and MPT-MWA (0%) (P = 0.73).

CONCLUSION

MPT-MWA may have improved therapeutic efficiency in the treatment of small HCCs.

Radiation Exposure of Interventional Radiologists during Computed Tomography Fluoroscopy-Guided Percutaneous Cryoablation

PURPOSE

The principal aim of this study was to evaluate radiation exposure of interventionalists during computed tomography (CT) fluoroscopy-guided percutaneous cryoablation (PCA) using radiophotoluminescent glass dosimeters (RPLDs). The radioprotective effects of safety glasses and lead apron were also evaluated.

MATERIALS AND METHODS

Radiation exposure of interventionalists during 46 CT fluoroscopy-guided PCA procedures was evaluated. Entrance surface dose (ESD) was measured using RPLDs on multiple sites: five sites, representing eye lens exposure; five sites, representing body exposure; and four sites, representing skin exposure. The ESD values on multiple sites were compared between different PCA procedures (renal, liver, and bone).

RESULTS

The mean ESD on the X-ray-side hand exhibited the highest value (358.8 μGy). Regarding evaluation sites representing exposure to the eye lens, the highest ESD inside the radiation protective glasses was detected on the X-ray-side cheek (167.1 μGy). Most ESD values among multiple sites (10/14) were linearly correlated with CT fluoroscopy time. Among them, the ESD values measured during renal and liver PCA were relatively higher than those measured during bone PCA, especially on the chest area outside the lead apron, and on the X-ray tube-side elbow and hand during renal and bone PCA. Radioprotective effects of safety glasses and lead apron ranged from 44.6 to 50.6% and from 30.2 to 79.6%, respectively, on each evaluation site.

CONCLUSION

The site with the highest radiation exposure on interventionalists during CT fluoroscopy-guided PCA was the X-ray tube-side hand. Radiation exposure of interventionalists was at acceptable levels and consistent with the recommended dose limits.

Percutaneous Image-guided Thermal Ablation for Renal Cell Carcinoma

Nephrectomy is the gold standard for the treatment of renal cell carcinoma (RCC). However, some patients are not suitable candidates for nephrectomy because of high surgical risk, reduced renal function, or the presence of multiple renal tumors. Percutaneous image-guided thermal ablation, including cryoablation and radiofrequency ablation, is a minimally invasive and highly effective treatment and can be used to treat RCC in patients who are not good candidates for surgery. This article will review percutaneous image-guided thermal ablation for RCC, covering treatment indications, ablation modalities and techniques, oncologic outcomes, and possible complications. In addition, the characteristics of each ablation modality and its comparison with nephrectomy are also presented.

Percutaneous Radiofrequency Ablation for Liver Tumors: Technical Tips

Percutaneous radiofrequency ablation (RFA) has been accepted as a minimally invasive therapeutic treatment for liver malignancies. Although RFA is usually applied for the treatment of small liver tumors (<3 cm), several technical developments have expanded the use of RFA. RFA is now used for the treatment of large liver tumors, and the number of complications associated with this treatment has decreased. These refinements may ultimately lead to better long-term prognosis. Here, we review recent refinements of liver RFA and provide technical tips.

Multimodality Therapy Including Proton Beam Therapy for AFP Producing Esophageal Cancer with Multiple Liver Metastases

A 50-year-old man who presented with a fever and epigastralgia was diagnosed to have esophageal carcinoma which was identified as poorly differentiated adenocarcinoma producing alpha-fetoprotein (AFP) with Barrett's esophagus. Computed tomography revealed multiple liver metastases and lymph node metastases surrounding the stomach. We first performed chemotherapy for the systemic lesions and proton beam therapy for the local control of lesions without complete remission and we were able to successfully control the frequently recurring lesions by proton beam therapy, cryotherapy and chemotherapy. A complete response has been maintained for 16 months and the overall survival time is 4 years and 2 months. Proton beam therapy for primary esophageal cancer and metastatic lesions was thus found to be an effective therapeutic option for such cases.