Effect of hepatic cyst size on postoperative outcomes: size is irrelevant

Abstract

Presenter: Michael Watson MD | Carolinas HealthCare System Background: Simple hepatic cysts may present with a wide range of sizes and symptomatology. There is no formal diagnostic schema for simple hepatic cysts, however previous studies have used various cut-offs to define a “giant” hepatic cyst. There have been few studies of the clinical implications of simple hepatic cyst size. Methods: Patients undergoing treatment of simple hepatic cysts at our institution between January 2008 to July 2019 were identified by retrospective record review. Demographic data, preoperative symptoms, cyst characteristics, surgical details, and postoperative outcomes were determined from retrospective record review. Cyst size was defined as the greatest measured diameter on axial imaging. If multiple cysts were present, the largest cyst size was used for analysis. Linear regression for continuous variables and logistic regression for categorical variables was used to determine correlations between cyst size and postoperative outcomes. Results: 120 patients with simple hepatic cysts were identified and included in our analysis. The average cyst size was 12.0±5.5 cm, 85.8% of patients were symptomatic, and pain (83.3%) was the predominant symptom. 114 (95%) of patients were treated with minimally invasive surgery, mean estimated blood loss (EBL) was 193±413 mL, mean operative time was 123±59 min, conversion to open rate was 1.8%, and the rate of simultaneous hepatectomy was 23.3%. Rate of reoperation for recurrence was 4.2%. Regression analysis considering size as a continuous variable demonstrated that cyst size was weakly correlated with operative time (R2=0.0683; p=0.0056), however it was not associated with EBL (p=0.4874), need for hepatectomy (p=0.4094), length of stay (p=0.1305), complications (p=0.2943), Clavien-Dindo grade of complications (p=0.4072), or reoperation for recurrence (p=0.2488). Regression analysis was then carried out to determine correlation between cyst percentile size and postoperative outcomes. Using cutoffs at the 10th, 25th, 50th, 75th, and 90th percentiles, there was no correlation between these cutoffs and operative time. There were no correlations between any percentile cut-offs and EBL, need for hepatectomy, length of stay, complications, or Clavien-Dindo grade of complications Conclusion: For surgical therapy of simple hepatic cysts there is a weak correlation with cyst size and operative time, however there is no correlation between clinically relevant patient outcomes and cyst size. This demonstrates that for patients with simple hepatic cysts, the size of the cyst does not predict patient outcomes. Traditional definitions of “giant” simple hepatic cysts are irrelevant.