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Does the status of the retroperitoneal margin affect survival for patients with resectable pancreatic cancer?
Mini Oral Session Abstracts drain insertions (OR 4.45), reintubation (OR 7.46), reoperation (OR 7.86), parenteral nutrition (OR 9.58) and cardiac resuscitation (OR 4.62) had increased adjusted odds of high costs. Compared to high-volume centers, low-volume centers were predictive of increased odds of high costs (OR 1.61 95% CI 1.25e2.07), but medium-volume centers were not (OR 1.12 95% CI 1.25e2.07). Conclusion: PD performed at high-volume centers was associated with lower costs for care. An association between severity of complication experienced and higher-cost was demonstrated.
S63
to achieve a greater than 2 mm margin from periadventitial dissection is reflective of good tumor biology and improved outcomes.
Table 1 Patients undergoing pancreaticoduodenectomy
grouped by Clavien–Dindo complication grade at 90 days post-operatively and patient costs associated with each complication grade. Cost reported in 2016 US$. Clavien–Dindo grade
n (%)
Mean cost (SD)
0 or 1
1228 (48.1)
24,407 (9,264)
2
208 (8.2)
36,433 (14,001)
3a
501 (19.6)
38,710 (19,292)
3b
143 (5.6)
47,230 (23,652)
4
472 (18.5)
61,235 (48,537)
MO 55 DOES THE STATUS OF THE RETROPERITONEAL MARGIN AFFECT SURVIVAL FOR PATIENTS WITH RESECTABLE PANCREATIC CANCER? B. Xia, A. Humaidi, V. Dhar, N. Levinsky, D. Hanseman, G. Wilson, Y. Kim, J. Sutton, J. Sussman and S. Ahmad University of Cincinnati, Cincinnati, OH, USA Objective: The significance of a positive pancreatic margin during pancreaticoduodenectomy remains controversial. Various studies have demonstrated that the uncinate or retroperitoneal margin (RP) is at highest risk for positive margin status. We sought to determine if tumor biology is predictive of obtaining a negative margin, and if the extent of RP margin clearance is of prognostic importance. Methods: A single institution, retrospective analysis was performed, identifying 176 patients who underwent a pancreaticoduodenectomy for pancreatic cancer between 2005 and 2015. Involvement of the RP margin (R1 resection) was defined as cancer within 1 mm of the surgical margin. Statistical analysis was performed using regression analyses and the KaplaneMeier method. Results: The majority of R1 resections (n = 42, 75%) involved the RP margin, with a median overall survival (OS) of 13.7 months, in comparison to 28.9 months for patients without RP margin involvement (P = 0.018). A positive RP margin was associated with nodal involvement, perineural and vascular invasion, and larger tumor size (all P < 0.05). Among patients with a negative RP margin, obtaining 2 mm clearance proffered a survival advantage compared to the traditional definition of 1 mm clearance (OS, 28.9 vs 18.5 months, P = 0.038). On multivariate analysis, perineural invasion, margin status, and nodal involvement persisted as independent prognosticators of OS. Conclusion: Our data indicates that a positive RP margin is related to both biological and technical factors. The ability
HPB 2017, 19 (S1), S40eS108
MO 56 IRREVERSIBLE ELECTROPORATION OF THE PANCREAS USING PARALLEL PLATE ELECTRODES IN A PORCINERNMODEL: A FEASIBILITY STUDY S. Rombouts, M. Nijkamp, W. van Dijck, L. Brosens, M. Konings, I. Borel Rinkes, J. Hagendoorn, F. Wittkampf and I. Molenaar University Medical Center Cancer Center Utrecht, Utrecht, Netherlands Objective: Irreversible electroporation (IRE) is being explored as treatment option in locally advanced unresectable pancreatic cancer. Several studies have shown promising results with IRE needles. Disadvantages are the technical difficulties for needle placement, the time needed to achieve tumor ablation and possible occurrence of postoperative pancreatic fistula via the needle tracks. The aim of this experimental study is to evaluate the feasibility of newly developed IRE-technique using two parallel metal paddles, in a porcine model. Methods: Twelve healthy pigs underwent laparotomy. Three parts of the pancreas were treated, each with a single application of either 50 or 100 joules (J) or a series of 4 applications of 50 J using a standard monophasic external cardiac defibrillator. After 6 hours, pancreatectomy was performed for histology and pigs were terminated. Results: Histology showed necrosis of pancreatic parenchyma with influx of neutrophils in 5/12, 11/12 and 12/12 of the ablated areas at 50, 100, and 4x 50 J respectively. The electric current density threshold to achieve necrosis was 4.3, 5.1 and 3.4 A/cm22 respectively. The ablation threshold was significantly lower for 4x 50 J compared to a single application of 50 or 100 J; (p = 0.003). Conclusion: Pancreatic tissue can successfully be ablated using two parallel paddles around the tissue. In the present study, a series of 4 applications of 50 J was most effective in creating a homogeneous necrotic lesions.
S63
to achieve a greater than 2 mm margin from periadventitial dissection is reflective of good tumor biology and improved outcomes.
Table 1 Patients undergoing pancreaticoduodenectomy
grouped by Clavien–Dindo complication grade at 90 days post-operatively and patient costs associated with each complication grade. Cost reported in 2016 US$. Clavien–Dindo grade
n (%)
Mean cost (SD)
0 or 1
1228 (48.1)
24,407 (9,264)
2
208 (8.2)
36,433 (14,001)
3a
501 (19.6)
38,710 (19,292)
3b
143 (5.6)
47,230 (23,652)
4
472 (18.5)
61,235 (48,537)
MO 55 DOES THE STATUS OF THE RETROPERITONEAL MARGIN AFFECT SURVIVAL FOR PATIENTS WITH RESECTABLE PANCREATIC CANCER? B. Xia, A. Humaidi, V. Dhar, N. Levinsky, D. Hanseman, G. Wilson, Y. Kim, J. Sutton, J. Sussman and S. Ahmad University of Cincinnati, Cincinnati, OH, USA Objective: The significance of a positive pancreatic margin during pancreaticoduodenectomy remains controversial. Various studies have demonstrated that the uncinate or retroperitoneal margin (RP) is at highest risk for positive margin status. We sought to determine if tumor biology is predictive of obtaining a negative margin, and if the extent of RP margin clearance is of prognostic importance. Methods: A single institution, retrospective analysis was performed, identifying 176 patients who underwent a pancreaticoduodenectomy for pancreatic cancer between 2005 and 2015. Involvement of the RP margin (R1 resection) was defined as cancer within 1 mm of the surgical margin. Statistical analysis was performed using regression analyses and the KaplaneMeier method. Results: The majority of R1 resections (n = 42, 75%) involved the RP margin, with a median overall survival (OS) of 13.7 months, in comparison to 28.9 months for patients without RP margin involvement (P = 0.018). A positive RP margin was associated with nodal involvement, perineural and vascular invasion, and larger tumor size (all P < 0.05). Among patients with a negative RP margin, obtaining 2 mm clearance proffered a survival advantage compared to the traditional definition of 1 mm clearance (OS, 28.9 vs 18.5 months, P = 0.038). On multivariate analysis, perineural invasion, margin status, and nodal involvement persisted as independent prognosticators of OS. Conclusion: Our data indicates that a positive RP margin is related to both biological and technical factors. The ability
HPB 2017, 19 (S1), S40eS108
MO 56 IRREVERSIBLE ELECTROPORATION OF THE PANCREAS USING PARALLEL PLATE ELECTRODES IN A PORCINERNMODEL: A FEASIBILITY STUDY S. Rombouts, M. Nijkamp, W. van Dijck, L. Brosens, M. Konings, I. Borel Rinkes, J. Hagendoorn, F. Wittkampf and I. Molenaar University Medical Center Cancer Center Utrecht, Utrecht, Netherlands Objective: Irreversible electroporation (IRE) is being explored as treatment option in locally advanced unresectable pancreatic cancer. Several studies have shown promising results with IRE needles. Disadvantages are the technical difficulties for needle placement, the time needed to achieve tumor ablation and possible occurrence of postoperative pancreatic fistula via the needle tracks. The aim of this experimental study is to evaluate the feasibility of newly developed IRE-technique using two parallel metal paddles, in a porcine model. Methods: Twelve healthy pigs underwent laparotomy. Three parts of the pancreas were treated, each with a single application of either 50 or 100 joules (J) or a series of 4 applications of 50 J using a standard monophasic external cardiac defibrillator. After 6 hours, pancreatectomy was performed for histology and pigs were terminated. Results: Histology showed necrosis of pancreatic parenchyma with influx of neutrophils in 5/12, 11/12 and 12/12 of the ablated areas at 50, 100, and 4x 50 J respectively. The electric current density threshold to achieve necrosis was 4.3, 5.1 and 3.4 A/cm22 respectively. The ablation threshold was significantly lower for 4x 50 J compared to a single application of 50 or 100 J; (p = 0.003). Conclusion: Pancreatic tissue can successfully be ablated using two parallel paddles around the tissue. In the present study, a series of 4 applications of 50 J was most effective in creating a homogeneous necrotic lesions.