Background Standardized future liver remnant (sFLR) volume and degree of hypertrophy after portal vein embolization (PVE) have been recognized as significant predictors of surgical outcomes after major liver resection. However, regeneration rate of the FLR after PVE varies among individuals and its clinical significance is unknown. Study Design Degree of hypertrophy at initial volume assessment divided by number of weeks elapsed after PVE was defined as the kinetic growth rate (KGR). In 107 consecutive patients who underwent liver resection for colorectal liver metastases with a sFLR volume of greater than 20%, the ability of the KGR to predict overall and liver-specific postoperative morbidity and mortality was compared with sFLR volume and degree of hypertrophy. Results Using receiver operating characteristic analysis, the best cut-off values for sFLR volume, degree of hypertrophy, and KGR for predicting postoperative hepatic insufficiency were estimated as, respectively, 29.6%, 7.5%, and 2.0% per week. Among these, KGR was the most accurate predictor (area under the curve, 0.830 [0.736-0.923]; asymptotic significance, 0.002). KGR of less than 2% per week vs. ≥2% per week correlate with rates of hepatic insufficiency (21.6% vs. 0%, p = 0.0001) and liver-related 90-day mortality (8.1% vs. 0%, P=0.04). The predictive value of KGR was not influenced by sFLR volume or the timing of initial volume assessment when evaluated within 8 weeks after PVE. Conclusions KGR is a better predictor of postoperative morbidity and mortality after liver resection for small FLR than conventional measured volume parameters (sFLR volume and degree of hypertrophy).

Background The primary reported indication for the Associating Liver Partition with Portal vein Ligation for Staged hepatectomy (ALPPS) technique is in patients with very low future liver remnant volumes. Given the elevated incidence of major morbidity (40%) and liver-related mortality (12%) with ALPPS, we sought to determine the safety and efficacy of percutaneous portal vein embolization (PVE) in a similar patient population. Patients and Methods Tumor resectability and morbidity/mortality rates were reviewed for 144 consecutive liver tumor patients with future liver remnant to body weight ratios (LR/BW) less than 0.5%. All patients were referred for preoperative percutaneous right plus segment IV PVE using embolic microspheres, with planned reassessment of the LR/BW 30 days after PVE. Post-PVE outcomes were compared to reported outcomes for ALPPS. Results Percutaneous PVE was successfully performed in 141 of the 144 study patients (97.9%). Adequate regeneration was observed in 139 patients (98.5%) with median post-PVE LR/BW rising from 0.33% to 0.52% (p<0.0001), representing a per-patient median regeneration of 62% (range: 0.3 – 379%). In total, 104 patients underwent extended right hepatectomy (n=102) or right hepatectomy (n=2). The remaining 40 patients (27.8%) were not resectable due to short-interval disease progression (27 patients, 18.5%), insufficient liver regeneration (5 patients, 3.5%), and medical comorbidities (8 patients, 5.6%). After resection, the following outcomes were observed: major morbidity: 33.0% (34/104), liver insufficiency: 12.5% (13/104), and 90-day liver-related mortality: 5.8% (6/104). These oncologic and technical results compare favorably to those of ALPPS. Conclusion Based on its ability to select oncologically resectable patients and superior safety and efficacy profiles, percutaneous right+segment IV PVE and interval surgery remains the standard of care for patients with very low future liver remnant volumes.

Background Patients with colorectal liver metastases (CLM) are increasingly treated with preoperative chemotherapy. Chemotherapy associated liver injury is associated with postoperative hepatic insufficiency (PHI) and mortality. The adequate minimum future liver remnant (FLR) volume in patients treated with extensive chemotherapy remains unknown. Methods All patients with standardized FLR >20 %, who underwent extended right hepatectomy for CLM from 1993–2011, were divided into three cohorts by chemotherapy duration: no chemotherapy (NC, n = 30), short duration (SD, ≤12 weeks, n = 78), long duration (LD, >12 weeks, n = 86). PHI and mortality were compared by using uni-/multivariate analyses. Optimal FLR for LD chemotherapy was determined using a minimum p-value approach. Results A total of 194 patients met inclusion criteria. LD chemotherapy was significantly associated with PHI (NC + SD 3.7 vs. LD 16.3%, p = 0.006). Ninety-day mortality rates were 0 % in NC, 1.3 % in SD, and 2.3% in LD patients, respectively (p = 0.95). In patients with FLR >30 %, PHI occurred in only two patients (both LD, 2/20, 10 %), but all patients with FLR >30 % survived. The best cutoff of FLR for preventing PHI after chemotherapy >12 weeks was estimated as>30 %. Both LD chemotherapy (odds ratio [OR] 5.4, p = 0.004) and FLR ≤ 30 % (OR 6.3, p = 0.019) were independent predictors of PHI. Conclusions Preoperative chemotherapy >12 weeks increases the risk of PHI after extended right hepatectomy. In patients treated with long-duration chemotherapy, FLR >30 % reduces the rate of PHI and may provide enough functional reserve for clinical rescue if PHI develops.

Background Percutaneous ablation is a common treatment for colorectal liver metastases (CLM). However, the effect of RAS mutation on outcome after ablation of CLMs is unclear. Methods Patients who underwent image-guided percutaneous ablation of CLMs from 2004 through 2015 and had known Rat sarcoma viral oncogene homolog (RAS mutation status were analyzed. Patients were evaluated for local tumor progression as observed on imaging at CLM treated with ablation. Multivariable Cox regression analysis was performed to determine factors associated with local tumour progression-free survival. Results The study included 92 patients who underwent ablation of 137 CLMs. Thirty-six patients (39%) had mutant RAS. Rates of local tumour progression were 14% (8/56) for patients with wild-type RAS and 39% (14/36) for patients with mutant RAS (p=0·007). Actuarial local tumour progression-free survival after percutaneous ablation were worse in patients with mutant RAS than wild-type RAS (3-year local tumour progression-free survival rate: 35% vs. 71%, p=0.001). In multivariable analysis, negative predictors of local tumour progression-free survival were minimal ablation margin <5 mm (hazard ratio [HR] 2·48, 95% confidence interval [CI] 1·31–4·72; p=0·006) and mutant RAS (HR 3·01, 95% CI 1·60–5·77; p=0·001). Conclusion Mutant RAS is associated with an earlier and higher rate of local tumour progression in patients undergoing ablation of CLM.

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