[Stereotaxy and robotics for ablation - toy or tool?].

UNLABELLED

CLINICAL AND METHODOLOGICAL ISSUES: Ablative technologies allow local curative tumor treatment by thermal tissue damage. An important prerequisite is the coverage of all tumor cells. Tumor size is the most important limiting factor.

STANDARD RADIOLOGICAL METHODS

The drawbacks of conventional computed tomography/ultrasound/magnetic resonance imaging (CT/US/MRI) guided radiofrequency ablation (RFA) are the absence of planning software, imprecise probe placement, imprecise control of probe placement and the ablation zone as well as the lack of reliability and reproducibility.

METHODOLOGICAL INNOVATIONS

Stereotactic and robot-assisted systems allow planning of multiple probe positions based on CT/MRI and positron emission tomography (PET) planning data. The probes can be precisely placed according to the coordinates of the image datasets.

PERFORMANCE

The 1 and 3 year survival rates after stereotactic RFA (SRFA) of cholangiocellular carcinoma were 91% and 70% respectively and the median overall survival was 60 months. After SRFA of 189 colorectal liver metastases in 63 patients there was no significant difference in local recurrence rates between tumors < 3 cm (17.7%), 3-5 cm (11.1%) and > 5 cm (17.4%). The median overall survival was 33.2 months and the 1, 3, and 5 year overall survival rates after SRFA in patients with resectable colorectal cancer were 92%, 66% and 48%, respectively.

ACHIEVEMENTS

In our opinion the excellent and, to a large extent user-independent results justify the increased efforts in time and costs especially for the treatment of patients with large and irregular tumors.

PRACTICAL RECOMMENDATIONS

Stereotaxy and robotics are valuable tools for effective tumor ablation especially of large tumors and are likely to gain in importance in the next few years.