Time-dependent impact of age and comorbidities on long-term overall survival after liver resection.

BACKGROUND & AIMS: Advanced age and comorbidities are known to be associated with increased perioperative risks after liver resection. However, the precise impact of these variables on long-term overall survival (OS) remains unclear. Thus, the aim of this study was to evaluate the confounder-adjusted, time-dependent effect of age and comorbidities on OS following hepatectomy for primary and secondary malignancies. METHODS: From a prospective database of 1.143 liver resections, 763 patients treated for primary and secondary malignancies were included. For time-varying OS calculations, a Cox-Aalen model was fitted. The confounder-adjusted hazard was compared with mortality tables of the German population. RESULTS: Overall, age (P = 0.003) and comorbidities (P = 0.001) were associated with shortened OS. However, time-dependent analysis indicated that age and comorbidities had no impact on OS within 39 and 55 months after resection respectively. From this time on, a significant decline in OS was shown. Subgroup analysis indicated an earlier increase of the effect of age in patients with hepatocellular carcinoma (17 months) than in those with colorectal metastases (70 months). The confounder-adjusted hazard of 70-year-old patients was increased post-operatively but dropped 66 months after surgery, and the risk of death was comparable to the general population 78 months after resection. At this time, one-third of patients aged 70 years and older were still alive. CONCLUSIONS: With regard to long-term outcome, liver resection for both primary and secondary malignancies should not be categorically denied due to age and comorbidities. This information should be considered for the patient selection process and informed consent.

Thirty-day mortality leads to underestimation of postoperative death after liver resection: A novel method to define the acute postoperative period.

BACKGROUND: Postoperative mortality commonly is defined as death occurring within 30 days of surgery or during hospitalization. After resection for liver malignancies, this definition may result in underreporting, because mortality caused by postoperative complications can be delayed as the result of improved critical care. The aim of this study was to estimate statistically the acute postoperative period (APP) after partial hepatectomy and to compare mortality within this phase to standard timestamps. METHODS: From a prospective database, 784 patients undergoing resection for primary and secondary hepatic malignancies between 2003 and 2013 were reviewed. For estimation of APP, a novel statistical method applying tests for a constant postoperative hazard was implemented. Multivariable mortality analysis was performed. RESULTS: The APP was determined to last for 80 postoperative days (95% confidence interval 40-100 days). Within this period, 55 patients died (7.0%; 80-day mortality). In comparison, 30-day mortality (N = 32, 4.0%) and in-hospital death (N = 39, 5.0%) were relevantly less. No patient died between postoperative days 80 and 90. The causes of mortality within 30 days and from days 30-80 did not greatly differ, especially regarding posthepatectomy liver failure (44% vs 39%, P = .787). Septic complications, however, tended to cause late deaths more frequently (43% vs 25%, P = .255). Comorbidities (Charlson comorbidity index ≥ 3; P = .046), increased preoperative alanine aminotransferase activity (P = .030), and major liver resection (P = .035) were independent risk factors of 80-day mortality. CONCLUSION: After liver resection for primary and secondary malignancies, 90-day rather than 30-day or in-hospital mortality should be used to avoid underreporting of deaths.