Innovation and Future Perspectives in the Treatment of Colorectal Liver Metastases

Technological advances and investigation into tumor biology have enhanced treatments of patients with colorectal liver metastases (CLM). This article briefly summarizes paradigm shifts in treatments of this disease in the following 4 sections. (1) Small metastases: The treatment of multiple and small CLM has evolved from anatomic resection to parenchyma-sparing hepatectomy. Survival after parenchyma-sparing hepatectomy was similar to or better than anatomic resection. The use of preoperative chemotherapy may cause tumor disappearance. However, the use of fiducial markers may aid in intraoperative localization. Post-resection completion ablation is a new useful treatment concept. It was defined as percutaneous ablation under cross-sectional imaging guidance to eradicate CLM which were intentionally unresected during latest surgery. (2) Bilateral (bilobar) metastases: Two-stage hepatectomy (TSH) is a well-established approach for treating multiple bilateral CLM. The use of hybrid operating room accelerates this sequence because it allows first-stage hepatectomy, portal vein embolization, and computed tomography in one hospitalization. This accelerated TSH sequence enables the second-stage hepatectomy within 4 weeks compared to 8 weeks using conventional TSH sequence. (3) Synchronous lung metastases: For patients with synchronous liver and lung metastases, simultaneous surgical approach is feasible. Specifically, a transdiaphragmatic approach enables simultaneous resection of liver and lung metastases via one abdominal incision. (4) Multiple mutation: Somatic gene mutation testing is increasingly used to evaluate tumor biology. Mutations in TP53, RAS, and SMAD4 affect prognosis through three different signaling pathways of colorectal carcinogenesis. This information can be used to change clinical decision-making regarding surveillance intensity and treatments for liver recurrence.