Erik M. Dunki-Jacobs

Evaluation of resistance as a measure of successful tumor ablation during irreversible electroporation of the pancreas.

BACKGROUND Intraoperative evaluation of successful pancreatic tumor ablation using irreversible electroporation (IRE) is difficult secondary to lack of visual confirmation. The IRE generator provides feedback by reporting current (amperage), which can be used to calculate changes in tumor tissue resistance. The purpose of the study was to determine if resistance can be used to predict successful tumor ablation during IRE for pancreatic cancers. STUDY DESIGN All patients undergoing pancreatic IRE from March 2010 to December 2012 were evaluated using a prospective database. Intraoperative information, including change in tumor resistance during ablation and slope of the resistance curve, were used to evaluate effectiveness of tumor ablation in terms of local failure or recurrence (LFR) and disease-free survival (DFS). RESULTS A total of 65 patients underwent IRE for locally advanced pancreatic cancer. Median follow-up was 23 months. Local failure or recurrence was seen in 17 patients at 3, 6, or 9 months post IRE. Change in tumor tissue resistance and the slope of the resistance curve were both significant in predicting LFR (p = 0.02 and p = 0.01, respectively). The median local disease-free survival was 5.5 months in patients who had recurrence compared with 12.6 months in patients who did not recur (p = 0.03). Neither mean change in tumor tissue resistance nor the slope of the resistance curve significantly predicted overall DFS. CONCLUSIONS Mean change in tumor tissue resistance and the slope of the resistance curve could be used intraoperatively to assess successful tumor ablation during IRE. Larger sample size and longer follow-up are needed to determine if these parameters can be used to predict DFS.

Evaluation of thermal injury to liver, pancreas and kidney during irreversible electroporation in an in vivo experimental model.

Irreversible electroporation (IRE) is a new technique for tumour cell ablation that is reported to involve non‐thermal‐based energy using high voltage at short microsecond pulse lengths. In vivo assessment of the thermal energy generated during IRE has not been performed. Thermal injury can be predicted using a critical temperature model. The aim of this study was to assess the potential for thermal injury during IRE in an in vivo porcine model.

Outcomes and prognostic factors in nodular melanomas

BACKGROUND The nodular subtype of cutaneous melanoma has a more pronounced vertical phase and less of a radial growth phase compared with other histologic subtypes. This study was performed to determine prognostic factors and outcomes for nodular melanomas. METHODS A post hoc analysis of a prospective clinical trial was performed in all patients with nodular histologic subtype. Univariate and multivariate analyses of factors associated with disease-free survival (DFS), overall survival (OS), and local and in-transit recurrence-free survival (LITRFS) were performed. Kaplan-Meier survival analyses were performed. RESULTS There were 736 patients available for analysis, and 189 (25.7%) were sentinel lymph node (SLN) positive. Breslow thickness of ≥2.3 mm, presence of ulceration, nonextremity tumor location, positive SLN, and non-SLN-positive status were independent risk factors for worse OS and DFS. Kaplan-Meier analysis demonstrated that ulceration predicted worse OS and DFS in all nodular melanoma patients, and in both SLN-positive and -negative subsets. The presence of ulceration and a positive SLN together predicted significantly worse DFS and OS. CONCLUSION The most important risk factors that determine prognosis in nodular melanomas are SLN status and ulceration. The presence of both a positive SLN and ulceration significantly affect DFS and OS, and to a lesser degree LITRFS.

Clinical evaluation of somatostatin use in pancreatic resections: Clinical efficacy or limited benefit?

BACKGROUND The benefit of somatostatin for the prevention of pancreatic fistula has been debated widely in the literature. The aim of this study was to evaluate the efficacy of somatostatin in preventing pancreatic fistulas and improving postoperative outcomes after pancreatic resection. HYPOTHESIS Somatostatin improves postoperative outcomes after pancreatectomy. METHODS A review was performed of a prospectively collected 2002 patient hepatopancreaticobiliary database. Patients were included if they underwent pancreatectomy between October 1, 2000, and May 16, 2012. Patients received somatostatin prophylactically at the discretion of their surgeon. Data were analyzed using univariate and multivariate analysis to determine if somatostatin had any effect on pancreatic fistula formation, fistula severity, duration of stay, and readmission rates. RESULTS We identified 510 patients who underwent pancreatectomy. Overall, patients 30 (6%) developed postoperative pancreatic fistulas and 27 (5%) fistulas were of clinical significance (grade B or C). Somatostatin was administered prophylactically to 215 (42%) patients, 57 patients (11%) were readmitted; the median duration of stay was 9 days (range, 2-81). Pancreatic fistula developed in 7 patients (3%) who received somatostatin versus 23 (8%) who did not receive somatostatin (P = .031). Among patients receiving somatostatin, 6 fistulas (3%) were of clinical significance versus 21 fistulas (7%) for patients who did not receive somatostatin (P = .031). Readmission occurred in 27 patients (13%) who received somatostatin versus 30 patients (10%) who did not receive somatostatin (P = .398). The median duration of stay was 9 days (range, 2-48) for patients who received somatostatin versus 9 days (range, 2-81) for patients who did not receive somatostatin (P = .462). CONCLUSION Somatostatin use was associated with a significant decrease in both the rate of fistula formation and the number of clinically important fistulas in our pancreatectomy patients. Continued evaluation of somatostatin use in relation to both intraoperative predictors and costa are needed to better define the population that will gain clinical benefit and cost savings.

The role of hepatic artery lymph node in pancreatic adenocarcinoma: prognostic factor or a selection criterion for surgery

BACKGROUND Hepatic artery lymph node (HALN) metastasis in pancreatic adenocarcinoma reportedly confers a survival disadvantage. This has led some authors to propose it as an indicator against pancreaticoduodenectomy (PD). METHODS Consecutive patients who underwent PD during 2002-2012 were identified from the University of Louisville prospective hepatopancreaticobiliary database. Overall survival (OS) and disease-free survival (DFS) were estimated using Kaplan-Meier analysis. The log-rank test and multivariate Cox proportional hazards regression were used in further analyses. RESULTS A total of 420 patients underwent PD during the period of study, of whom 197 had lymph node (LN) metastasis. Among these, 41 (20.8%) patients had disease-positive HALNs. The HALN was the only site of LN metastasis in only three of the 247 patients (1.2%). Median follow-up was 18.5 months (interquartile range: 4.1-28.2 months). Median OS and DFS were 22.7 months [95% confidence interval (CI) 19.0-26.3] and 12.6 months (95% CI 10.2-15.2). There was no significant difference in median OS between HALN-positive patients (18.4 months, 95% CI 12.3-24.0) and HALN-negative patients (19.7 months, 95% CI 16.7-22.6) (P = 0.659). On multivariate analysis, the hazard ratio (HR) of death was highest among patients with an LN ratio of >0.2 (HR 1.2, 95% CI 1.1-1.29; P = 0.012) followed by those with poorly differentiated histology (HR 1.09, 95% CI 1.04-1.11; P = 0.029). CONCLUSIONS In pancreatic adenocarcinoma patients with LN disease, survival after PD is comparable regardless of HALN status. Therefore, HALN-positive disease should not preclude the performance of PD.