How to increase the resectability of initially unresectable colorectal liver metastases: A surgical perspective

Abstract

Although surgical resection is the only treatment of choice that can offer prolonged survival and a chance of cure in patients with colorectal liver metastases (CRLM), nearly 80% of patients are deemed to be unresectable at the time of diagnosis. Considerable efforts have been made to overcome this initial unresectability, including expanding the indication of surgery, the advent of conversion chemotherapy, and development and modification of specific surgical techniques, regulated under multidisciplinary approaches. In terms of specific surgical techniques, portal vein ligation/embolization can increase the volume of future liver remnant and thereby reduce the risk of hepatic insufficiency and death after major hepatectomy. For multiple bilobar CRLM that were traditionally considered unresectable even with preoperative chemotherapy and portal vein embolization, two-stage hepatectomy was introduced and has been adopted worldwide with acceptable short- and long-term outcomes. Recently, ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) was reported as a novel variant of two-stage hepatectomy. Although issues regarding safety remain unresolved, rapid future liver remnant hypertrophy and subsequent shorter intervals between the two stages lead to a higher feasibility rate, reaching 98%. In addition, adding radiofrequency ablation and vascular resection and reconstruction techniques can allow expansion of the pool of patients with CRLM who are candidates for liver resection and thus a cure. In this review, we discuss specific techniques that may expand the criteria for resectability in patients with initially unresectable CRLM.

Keywords: ALPPS; colorectal liver metastases; conversion surgery; two‐stage hepatectomy.

Figure 1

Three material factors for increasing resectability. EHD, extrahepatic disease; ALPPS, associating liver partition and portal vein ligation for staged hepatectomy

Figure 2

Scheme of staged hepatectomy for colorectal liver metastases. (A) Right‐first approach: most of the invaded hemiliver (usually the right lobe) is resected at the first stage, leading to hypertrophy of the contralateral liver lobe. At the second stage, tumor cleaning of the future liver remnant (FLR) is performed, usually by non‐anatomical partial resection. (B) Left‐first approach with portal vein ligation/embolization (PVL/PVE): The less invaded liver lobe (FLR, usually the left lobe) is cleaned of its metastases in combination with intraoperative PVL/PVE at the first stage. At the second stage, the tumor‐bearing liver lobe (deportalized liver lobe) is anatomically removed. (C) Left‐first approach followed by PVE: percutaneous PVE is performed between the first and second stages. (D) ALPPS: the less invaded liver lobe is cleaned of its metastases in combination with intraoperative PVL/PVE and in situ splitting of the hemiliver at the first stage. At the second stage, usually 7‐14 days later, the tumor‐bearing liver lobe is removed