Abstract
In contrast to surgical therapy and cytostatic therapy, locally ablative treatment of colorectal liver metastases is still lacking of large controlled trials to definitely prove its benefit on patient survival. Despite this, many different modalities have been developed for minimal invasive locoregional treatment, such as thermotherapy (radiofrequency ablation, laser induced thermotherapy) or brachytherapy (interstitial brachytherapy, transarterial radioembolization). As all of these modalities are performed under imaging guidance, success and risk strongly depends on the imaging strategy chosen for patient evaluation, treatment monitoring, and follow-up. There are not yet comprehensive guidelines on the use of locally ablative therapies, and, even more so, the use of diagnostic imaging largely depends on individual experiences and policies. Beyond oncological routines, the planning and monitoring of locally ablative treatment pose specific demands on the available imaging procedures. Many innovative applications of ultrasound, CT, MRI, PET and SPECT help to fulfill these requirements. Algorithms are needed for pretherapeutic decision making regarding the appropriate treatment strategy, as well as for posttherapeutic follow-up to confirm local control and to rule out new disease. This review summarizes current opinions to the use of diagnostic imaging in the scope of different image guided therapy modalities. Important, partly unpublished data for comprehensive pre- and posttherapeutic imaging algorithms is worked up. It also outlines challenges and possible solutions for improved guidance and monitoring of minimal invasive locoregional cancer treatment.
Keywords: Image guided tumor ablation, PET, MRI, CT, colorectal cancer, liver metastases, radiofrequency ablation (RFA), laser induced thermotherapy (LITT), CT-guided brachytherapy, transarterial radioembolization (SIRT)
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