The expanded toolbox of treatment options for colorectal liver metastases: Embracing a multidisciplinary approach

As the incidence of colorectal liver metastases (CRLM) is currently rising, there is an increasing need for multidisciplinary approach to treat these metastases. The key objective of this thesis is to describe the current local treatment modalities and assess their technical effectiveness, as well as their impact on disease and survival outcomes in patients with CRLM. Furthermore, this research aims to evaluate and compare various emerging technique advancements. An underlying emphasis of this thesis lies in advocating for the embracement of a multidisciplinary approach that engages surgical oncologists, medical oncologists, interventional radiologists, radiation oncologists, and other healthcare experts in the treatment of CRLM to optimize patient outcomes. Prognostic factors play an important role in the choice of treatment for colorectal liver metastases. In Part I the primary tumor origin and molecular profile are taken into account. Part II of this thesis reveals the substantive technical advancements that have influenced the present-day position of thermal ablation in the treatment of CRLM. Part III discusses the comparison of several treatment modalities for CRLM, including thermal ablation, irreversible electroporation, surgery and radiotherapy. The goal is to gain a comprehensive understanding of their respective strengths, limitations, impact on survival outcomes, and current roles in clinical practice. Thermal ablation has emerged as a prominent player in the management of CRLM. While the mentioned local treatment options have demonstrated effectiveness, a significant challenge persists: recurrence occurs in 64% to 85% of all locally treated patients, often within the first year. Part IV addresses treatment options for recurrent CRLM. Surprisingly, there is no universally accepted consensus in national or international guidelines on the best approach to manage recurrent CRLM. In conclusion, this thesis highlights the current toolbox of treatment options for CRLM, technical progress made for thermal ablation, discusses factors affecting treatment decisions and addresses therapeutic strategies for recurrent CRLM. Ongoing research like the COLLISION trial series (including XL and RELAPSE trial) aims to provide clarity in this evolving landscape.