Borderline resectable for colorectal liver metastases: Present status and future perspective

Table 1 Definition and treatment strategy for borderline resectable colorectal liver metastases in previous studies

Ref.	Definition	Treatment	Prognosis
Jones et al[44], 2013	Synchronous (< 12 mo); Bilobar diseases: Number ≥ 4; Size ≥ 5 cm; CEA ≥ 100 ng/mL	NAC (FOLFOX)	-
Worni et al[45], 2014	Bilobar diseases; Proximity to vascular or biliary structure; Low FLR	NAC	-
Qadan et al[3], 2015	Low FLR (< 20%, < 2 contiguous segments); Extrahepatic diseases; R1: Number ≥ 4	NAC (doublet or triplet)	-
Kaczirek et al[42], 2017	-	NAC (doublet + bevacizumab)	-
Phelip et al[49], 2016	3 ≤ Number < 8; ≤ 6 segments involvement; Without infiltration of HA, HV, and PV; Extrahepatic diseases ≤ 2	NAC (FOLFIRI)	3-yr PFS: 23.3%; 3-yr OS: 66.1%
Van Cutsem et al[43], 2016	Extrahepatic diseases: Number ≥ 5; Tumor progression	NAC (doublet or triplet)	-
Pietrantonio et al[46], 2017	> 1 hepatic vein involvement; > 4 segments involvement; Necessity of RFA or TSH; Number ≥ 4; Synchronous	Pre/post 4 cycle chemotherapy (COI-E)	Median PFS 17.8 mo; Median OS 62.5 mo
Bonadio et al[47], 2019	Number ≥ 4; Proximity to vascular or biliary structure	NAC (mFLOX)	Median PFS 16.9 mo; Median OS 68.3 mo
Ichida et al[48], 2019	Number ≥ 4; Size ≥ 5 cm; Extrahepatic diseases	NAC (doublet)	BR-NAC vs resectable: 5-yr RFS: 22.1% vs 46.5%, P = 0.02; 5-yr OS: 66.6% vs 74.0%, P = 0.40

CEA: Carcinoembryonic antigen; FLR: Future liver remnant; HA: Hepatic artery; HV: Hepatic vein; PV: Portal vein; RFA: Radiofrequency ablation; TSH: Two-stage hepatectomy; NAC: Neoadjuvant chemotherapy; FOLFOX: Infusional 5-fluorouracil, leucovorin, and oxaliplatin; COI-E: Cetuximab, irinotecan, oxaliplatin, and capecitabine; mFLOX, modified fluorouracil, leucovorin, and oxaliplatin; PFS: Progression-free survival; OS: Overall survival; BR: Borderline resectable; RFS: Recurrence-free survival.