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

Evidence on percutaneous radiofrequency and microwave ablation for liver metastases over the last decade

Purpose

This review aimed to summarize the treatment outcomes of percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) for metastatic liver tumors based on the findings of published studies over the last decade.

Materials and methods

Literature describing the survival outcomes of ablation therapy for liver metastases was explored using the PubMed database on April 26, 2022, and articles published in 2012 or later were selected. The included studies met the following criteria: (i) English literature, (ii) original clinical studies, and (iii) literature describing overall survival (OS) of thermal ablation for metastatic liver tumors. All case reports and cohort studies with fewer than 20 patients and those that evaluated ablation for palliative purposes were excluded.

Results

RFA was the most commonly used method for ablation, while MWA was used in several recent studies. RFA and MWA for liver metastases from various primary tumors have been reported; however, majority of the studies focused on colorectal cancer. The local control rate by RFA and MWA varied widely among the studies, ranging approximately 50–90%. Five-year survival rates of 20–60% have been reported following ablation for colorectal liver metastases by a number of studies, and several reports of 10-year survival rates were also noted.

Conclusion

Comparative studies of local therapies for colorectal liver metastases demonstrated that RFA provides comparable survival outcomes to surgical metastasectomy and stereotactic body radiation therapy.

Accuracy assessment of a potential clinical use of navigation-guided intra-operative liver metastasis brachytherapy-a planning study

For patients with inoperable liver metastases, intra-operative liver high dose-rate brachytherapy (HDR-BT) is a promising technology enabling delivery of a high radiation dose to the tumor, while sparing healthy tissue. Liver brachytherapy has been described in the literature as safe and effective for the treatment of primary or secondary hepatic malignancies. It is preferred over other ablative techniques for lesions that are either larger than 4 cm or located in close proximity to large vessels or the common bile duct. In contrast to external beam radiation techniques, organ movements do not affect the size of the irradiated volume in intra-operative HDR-BT and new technical solutions exist to support image guidance for intra-operative HDR-BT. We have retrospectively analyzed anonymized CT datasets of 5 patients who underwent open liver surgery (resection and/or ablation) in order to test whether the accuracy of a new image-guidance method specifically adapted for intra-operative HDR-BT is high enough to use it in similar situations and whether patients could potentially benefit from navigation-guided intra-operative needle placement for liver HDR-BT.

Application of laparoscopic ultrasound in robot-assisted minimally invasive therapy for abdominal tumors

AIM: To assess the clinical application of laparoscopic ultrasound in robot-assisted minimally invasive therapy for abdominal tumors.

METHODS: A total of 41 patients (16 patients with hilar cholangiocarcinoma, 15 patients with hepatic tumors, 9 patients with pancreatic tumors, and 1 patient with retroperitoneal tumor) underwent laparoscopic ultrasound-guided robot-assisted minimally invasive therapy for abdominal tumors. Laparoscopic ultrasound was used preoperatively to detect the number of lesions, and evaluate their location and relationship with surroundings tissue precisely. Also, by means of laparoscopic ultrasound, the surgical pathways were guided operatively, and preliminary clinical effects were evaluated postoperatively. To assess clinical efficacy, all patients were followed by contrast-enhanced CT/MRI, ultrasound, blood tests, etc.

RESULTS: All laparoscopic ultrasound-guided procedures were performed successfully. Laparoscopic ultrasound discovered undetected lesions in 10 patients, which resulted in a change in operative strategy (10/41, 24.39%). No death occurred during the perioperative period. Abnormalities were not found postoperatively by ultrasound and contrast-enhanced CT/MRI in all patients. Laboratory studies demonstrated that blood biochemical indicators decreased to normal range gradually. No severe complications occurred in both intraoperative and postoperative periods. All patients survived, and their life quality was improved significantly.

CONCLUSION: Laparoscopic ultrasound could not only guide operative strategy, but also help to decrease complications and prolong disease-free survival in the postoperative period. This technique provides a safe surgical procedure, and the therapeutic effects could be improved by application of laparoscopic ultrasound in robot-assisted minimally invasive therapy for abdominal tumors.