Current strategies in interventional oncology of colorectal liver metastases

Abstract

The adequate treatment of non-resectable liver metastases from colorectal cancer which are resistant to systemic chemotherapy currently provides a great challenge. The aim is to identify and review key strategies in the treatment of colorectal liver metastases. A search for current literature on the topic of interventional strategies for colorectal metastases was performed in Medline in order to achieve this goal. Studies before 2005 and with ,20 patients treated for colorectal metastases were excluded. Transarterial chemoembolization (TACE), transarterial embolization and selective internal radiation therapy (SIRT) were identified as examples of regional strategies for colorectal liver metastases, utilizing the unique blood supply of the liver. Radiofrequency ablation (RFA), microwave ablation (MWA) and cryoablation were selected as examples for currently available ablative techniques. Median survival in the key studies reviewed ranged from 7.7 to 28.6 for TACE, 8.3-12.6 for SIRT, 8.2-53.2 for RFA and 29-43 months for MWA. After review of the literature, it can be concluded that interventional oncologic therapies are a safe and effective method for treating colorectal liver metastases. The use of new chemotherapeutic agents for local therapy and new ablation technologies and techniques may increase patient survival and allows a neoadjuvant therapy setting. In addition, a combination of local therapies may be used to increase effectiveness in the future, which is subject to further research. INTRODUCTIONColorectal cancer is one of the most common cancers that shows fatal progression.1 Colorectal carcinoma most commonly metastasises to the liver due to haematogenous spread.2 At the time of diagnosis, 20-30% of patients have liver metastases, and during the course of disease, up to 60% of patients develop hepatic metastases.3 Although surgical excision is the first-line treatment for colorectal metastases, only 10-25% of patients are candidates for surgical resection. 4 Neoadjuvant systemic chemotherapy only allows 10-30% of patients with unresectable colorectal liver metastases sufficient downsizing for resection.

Updated survival outcomes and analysis of long-term survivors from the MORE study on safety and efficacy of radioembolization in patients with unresectable colorectal cancer liver metastases

“…For patients with unresectable colorectal cancer liver metastases that are refractory to first-line chemotherapy, a variety of interventional radiological procedures may also be considered (4)(5)(6). One such treatment is radioembolization (RE), also known as selective internal radiation therapy (SIRT), with yttrium-90-labeled ( 90 Y) microspheres.…”

“…This treatment modality consists of the selective delivery of radioactively labeled particles to liver tumors via the hepatic artery. Selective delivery of 90 Y microspheres to tumors can be achieved because hepatic tumors receive most of their blood supply from the hepatic artery, while normal hepatic tissue receives blood mainly from the portal vein (4,7).…”

Transarterial chemoembolization with raltitrexed-based or floxuridine-based chemotherapy for unresectable colorectal cancer liver metastasis

“…If the previous chemotherapy has failed, transarterial chemoembolization (TACE) is considered as an alternative option for CRCLM. TACE has been demonstrated to have a higher tumor response rate and lower adverse effects than systemic chemotherapy [11,12].…”

Ablative Verfahren in der Therapie von Lebermetastasen

“…Als Beispiel für ein kommerzielles System produziert der Applikator dabei Mikrowellen mit einer Leistung von 100 W und einer Frequenz von 0,9-2,45 GHz. Im Gewebe werden Temperaturen um die 100°C erreicht [8,9]. Die RFA erfolgt bspw.…”

“…Die Gewebetemperaturen liegen mit 65-70°C unter denen der MWA. Durch die applizierte Energie kommt es bei beiden Techniken zu Koagulationsnekrosen im gesunden und tumorösen Gewebe [8,9].…”