The Management of Colorectal Cancer Liver Metastases: The Interventional Radiology Viewpoint

The Role of Percutaneous Ablation in the Management of Colorectal Cancer Liver Metastatic Disease

Approximately 50% of colorectal cancer patients will develop metastases during the course of the disease. Local or locoregional therapies for the treatment of liver metastases are used in the management of oligometastatic colorectal liver disease, especially in nonsurgical candidates. Thermal ablation (TA) is recommended in the treatment of limited liver metastases as free-standing therapy or in combination with surgery as long as all visible disease can be eradicated. Percutaneous TA has been proven as a safe and efficacious therapy offering sustained local tumor control and improved patient survival. Continuous technological advances in diagnostic imaging and guidance tools, the evolution of devices allowing for optimization of ablation parameters, as well as the ability to perform margin assessment have improved the efficacy of ablation. This allows resectable small volume diseases to be cured with percutaneous ablation. The ongoing detailed information and increasing understanding of tumor biology, genetics, and tissue biomarkers that impact oncologic outcomes as well as their implications on the results of ablation have further allowed for treatment customization and improved oncologic outcomes even in those with more aggressive tumor biology. The purpose of this review is to present the most common indications for image-guided percutaneous ablation in colorectal cancer liver metastases, to describe technical considerations, and to discuss relevant peer-reviewed evidence on this topic. The growing role of imaging and image-guidance as well as controversies regarding several devices are addressed.

The Dutch-Belgian Registry of Stereotactic Body Radiation Therapy for Liver Metastases: Clinical Outcomes of 515 Patients and 668 Metastases

PURPOSE

Although various studies have reported that stereotactic body radiation therapy (SBRT) for liver metastases has high local control rates and relatively low toxicity, most series included a small number of patients. We aimed to validate these outcomes in a large multi-institution patient cohort treated in accordance with a common protocol.

METHODS AND MATERIALS

A shared web-based registry of patients with liver metastases treated with SBRT was developed by 13 centers (12 in the Netherlands and 1 in Belgium). All the centers had previously agreed on the items to be collected, the fractionation schemes, and the organs-at-risk constraints to be applied. Follow-up was performed at the discretion of the centers. Patient, tumor, and treatment characteristics were entered in the registry. Only liver metastases treated individually as independent targets and with at least 1 radiologic follow-up examination were considered for local control analysis. Toxicity of grade 3 or greater was scored according to the Common Terminology Criteria of Adverse Events (v4.03).

RESULTS

Between January 1, 2013, and July 31, 2019, a total of 515 patients were entered in the web-based registry. The median age was 71 years. In total, 668 liver metastases were registered, and 447 were included for local control analysis. The most common primary tumor origin was colorectal cancer (80.3%), followed by lung cancer (8.9%) and breast cancer (4%). The most-used fractionation scheme was 3x18-20 Gy (36.0%), followed by 8x7.5 Gy (31.8%), 5x11-12 Gy (25.5%), and 12x5 Gy (6.7%). The median follow-up time was 1.1 years for local control and 2.3 years for survival. Actuarial 1-year local control was 87%; 1-year overall survival was 84%. Toxicity of grade 3 or greater was found in 3.9% of the patients.

CONCLUSIONS

This multi-institutional study confirms the high rates of local control and limited toxicity in a large patient cohort. Stereotactic body radiation therapy should be considered a valuable part of the multidisciplinary approach to treating liver metastases.

The evolution of interventional oncology in the 21st century

Interventional oncology (IO) has proven to be highly efficient in the local therapy of numerous malignant tumors in addition to surgery, chemotherapy, and radiotherapy. Due to the advent of immune-oncology with the possibility of tumor control at the molecular and cellular levels, a system change is currently emerging. This will significantly rule oncology in the coming decades. Therefore, one cannot think about IO in the 21st century without considering immunology. For IO, this means paying much more attention to the immunomodulatory effects of the interventional techniques, which have so far been neglected, and to explore the synergistic possibilities with immuno-oncology. It can be expected that the combined use of IO and immuno-oncology will help to overcome the limitations of the latter, such as limited local effects and a high rate of side-effects. To do this, however, sectoral boundaries must be removed and interdisciplinary research efforts must be strengthened. In case of success, IO will face an exciting future.

Current status of stereotactic body radiotherapy for the treatment of hepatocellular carcinoma

Stereotactic body radiotherapy (SBRT) is an advanced form of radiotherapy (RT) with a growing interest on its application in the treatment of hepatocellular carcinoma (HCC). It can deliver ablative radiation doses to tumors in a few fractions without excessive doses to normal tissues, with the help of advanced modern RT and imaging technologies. Currently, SBRT is recommended as an alternative to curative treatments, such as surgery and radiofrequency ablation. This review discusses the current status of SBRT to aid in the decision making on how it is incorporated into the HCC management.