Curative in situ ablation of colorectal liver metastases—experimental and clinical implementation

Abstract

On the basis of experimental data, the aim of complete local tumor control (R0 ablation) can only be obtained if additional energy is applied after reaching the tumor-adapted maximal coagulation volume. Analogous to the oncological safety margin in surgical resection, we defined this decisive energy difference as the "energy safety margin" for in situ ablation. The energy safety margin is the energy that must be additionally applied after reaching the plateau in the energy/volume curve to achieve complete tumor coagulation. In addition to that, in situ ablation should be combined with temporary interruption of hepatic perfusion whenever possible to prevent intralesional recurrences. In this way, the thermoprotective mechanism of hepatic perfusion can be effectively eliminated. With restrictions, the survival data after ablation in specialized centers is comparable to surgical resection with concomitantly lower morbidity and mortality. Based on recent findings and with the corresponding expertise in the field of ablation and state-of-the-art equipment, ablation is, thus, an alternative to surgical resection. The combined application of surgical resection and ablation is also a suitable method for increasing the R0 rate and thus helps improve the prognosis of treated patients. In summary, it can be said that in situ ablation is a useful expansion of the therapeutic spectrum of liver metastases and can be applied as an alternative to or in combination with surgical resection.

Magnetic Resonance–Guided Laser-Induced Interstitial Thermotherapy of Breast Cancer Liver Metastases and Other Noncolorectal Cancer Liver Metastases

“…Furthermore, the volumes of treated metastases seemed to be a prognostic factor for long-term and progression-free survival as well. For example, Isbert et al 30 found significantly less local recurrences after in situ ablation for small-sized tumors of 3 cm in diameter or smaller. Solbiati et al 29 published comparable results using radiofrequency ablation: the local recurrence rate was between 21.6% for metastases up to a diameter of 2.5 cm and 68.4% for lesions 4.1 cm or larger.…”

Diagnostik und Therapie von Lebermetastasen kolorektaler Karzinome - Workflow

“…! [2,3,37,39,47,53,92,105,125,141] Allgemeines Evidenzlage der In-situ-Ablation " Niedrige Morbidität / Mortalität " 5-Jahres-Überleben in (ungünstig) selektionierten Studien für nicht-resektable Metastasen vergleichbar zur alleinigen chirurgischen Resektion (Evidenz-Level III) " Vergleichsdaten LITT / RFA (Laserinduzierte Interstitielle Thermotherapie / Radiofrequenzablation) fehlen " Fehlende Angaben über 5-Jahres-Überleben nach Ablation resektabler kolorektaler Lebermetastasen " Der Effekt der RFA auf das Lanzeitüberleben verglichen mit einer alleinigen Chemotherapie ist nicht geklärt. " In den vorliegenden Studien über die Ergebnisse der ablativen Verfahren sind die Patientenkollektive unzureichend charakterisiert (fehlende Prognose-Scores).…”

Interventionelle nichtchirurgische Therapie von Lebermetastasen

“…Während bei chirurgischen Therapien die R0-Resektion histologisch überprüft werden kann, ist dies bei den nichtchirurgischen Interventionen nicht möglich [12]. Deshalb wird ein Sicherheitsabstand von 1 cm um den abladierten Tumor propagiert [13]. Bei hyperthermen Methoden (Radiofrequenzablation (RFA), LITT, perkutane Mikrowellen-Koagulationstherapie (PMCT)) werden Ablationstemperaturen von 60-100 °C angestrebt, bei denen irreversible Proteindenaturierungen und Koagulationsnekrosen auftreten.…”