FLORIDA DIFFICULTY INDEX FOR ROBOTIC HEPATECTOMY: PROPOSAL OF A NEW DIFFICULTY SCORING SYSTEM

Background
Management of patients with margin negative, T1-T3, N0 (stage IB–IIIA), resected gallbladder cancer (GBC) remains poorly defined. Current guidelines consider observation, chemotherapy (CT), and chemoradiation (CRT) as options. The current study investigates the impact of CT/CRT on overall survival (OS) in these patients.

Methods
Patients with R0 resected stage IB–IIIA GBC were identified within the National Cancer Database. Relevant patient, tumor, and treatment data were analyzed. Multiple logistic regressions were performed for factors associated with receipt of hepatectomy and CT/CRT. Kaplan-Meier analysis for OS was performed. Logrank tests compared OS between treatment groups. Stage-by-stage multivariable Cox regressions assessed the impact of CT and CRT on mortality while adjusting for other risk factors.

Results
Of 2,070 patients identified, resection included cholecystectomy in 950 (45.9%) and cholecystectomy+hepatectomy in 1,120 (54.1%). Overall, 1,419 had resection alone (68.6%), 313 had resection+CT (15.1%), and 338 had resection+CRT (16.3%). Hepatectomy was more commonly performed at academic facilities (OR 2.538; CI 1.969-3.281; P<.01) and for stage IIIA disease (OR 2.670; CI 1.913-3.742; P<.01). Hepatectomy was associated with improved OS in stage IB-IIIA disease (logrank P<.01). Receipt of CT or CRT was associated with stage IIA-IIIA disease, hepatectomy, and private insurance (all P<.05). In univariable analysis, both CT (logrank P<.05) and CRT (logrank P<.01) were associated with improved OS only in patients with stage IIA-IIB disease who did not undergo hepatectomy. Within a multivariable Cox regression model adjusting for age, gender, comorbidities, insurance status, facility type, and tumor grade, only CRT was associated with decreased mortality for patients with stage IIA-IIB disease who did not undergo hepatectomy (HR 0.609; CI 0.400-0.888; P<.05).

Conclusions
The current national study demonstrates the importance of adequate surgical therapy for patients with potentially curable GBC. Among these patients, CT and CRT were not associated with improved OS. However, CRT did result in an OS benefit in patients who did not undergo optimal resection. Prospective trials focused on CT/CRT for adequately resected, node negative GBC are needed.

Introduction: The robotic platform is gaining a wider adoption in minimally invasive liver surgery, especially for complex resections. Difficulty scoring systems are a useful tool to predict the technical difficulty of each hepatectomy and to guide surgeons during operative planning. To date, difficulty scoring systems are available for laparoscopic but not for robotic hepatectomy. Because the robotic platform has unique technical characteristics when compared to the laparoscopic method in liver surgery, there is a need to design a difficulty scoring system specifically for robotic hepatectomy which we propose herein.
Methods: 328 consecutive patients undergoing robotic hepatectomy from a single institution were utilized to develop a difficulty scoring system. Patients requiring concomitant colorectal resection or undergoing planned conversion to ‘open’ hepatectomy were excluded. Operative duration and estimated blood loss (EBL) were utilized, among many markers, reflecting operative difficulty. Multivariate analysis was applied to determine the relationships between these markers of difficulty and relevant clinical factors.
Clinical factors utilized in the proposed robotic DSS were compiled after a comprehensive review of factors used by previously published IWATE, Institut Mutualiste Montsouris, and Southampton laparoscopic difficulty scoring systems, in addition to other relevant variables.
Every patient was given a corresponding robotic difficulty score and subsequently categorized into four groups based on their cumulative score (Group 1: 1-6, Group 2: 7-10, Group 3: 11-15, Group 4: 16-21). Patients’ perioperative outcomes between each group was compared. Data are presented as median(mean±SD). Significance was accepted at p≤0.05.
Results: Past surgical history, use of neoadjuvant chemotherapy, tumor location, tumor size, tumor type, proximity to major vessels, extent of parenchymal resection, need for portal lymphadenectomy, and need for biliary resection/reconstruction were significantly correlated with either operative time and/or EBL. Upon further analysis, 22 (7%) patients received a score of 1-6, 143 (44%) patients received a score of 7-10, 154 (47%) received a score of 11-15, and 9 (3%) patients received a score greater than 16. When stratified by difficulty score, there was a significant difference in patients’ Childs-Pugh score, rate of major resection, 30-day readmission, total cost, and fixed direct cost(p≤0.05).
Conclusions: Herein, we propose a novel difficulty scoring system (Table 1) for robotic hepatectomy utilizing clinical factors mentioned, which reflect technical difficulty. A further validation of this robotic difficulty scoring system is needed using larger multi-institutional collaborative datasets.