Reply to: The Letter to the Editor “Randomized Controlled Trial of Pancreaticojejunostomy versus Stapler Closure of the Pancreatic Stump During Distal Pancreatectomy to Reduce Pancreatic Fistula”
First, the debaters comment that this discrepancy between estimated rate and actual rate of pancreatic fistula would be due to an element of inexperience for PJ. However, this comment from the debaters is not true and the debaters have to find our efforts to uniform the surgical level regarding PJ before the starting of this RCT. Indeed, in participating institutions, pancreatic surgeons participating in this trial have visited to the principal institution, Wakayama Medical University, to learn how to perform the anastomosis and how to perform the stump closure during December 2010 to June 2011(6 months). Moreover, the institutions in this RCT are definitely high volume centers of pancreatic surgery and the experiences of PJ have been maturated in Whipple operation. Therefore, we absolutely deny the comment of the debaters that the result of PJ in this study was due to an element of inexperience.
The second comment is that current size of this RCT may be small. We have to refer other previous literatures to calculate sample size of RCT. Therefore, when pancreatic fistula rate in PJ of the pancreatic stump ranges from 0% to 8.6% in other previous literatures,2–4 5% was expected as pancreatic fistula rate in the PJ group at the design of this protocol. Thus, pancreatic fistula rate was estimated to reduce from 25% to 5% by PJ of the pancreatic stump. On the basis of this hypothesis, the value of 124 patients as sample size was calculated to show a difference between the 2 groups at a power of 80% with a significance level of 0.05. The incidence of pancreatic fistula in other previous literatures might be incidental rate in underpowered studies. However, sample size was correctly calculated on the basis of the hypothesis. In addition, the authors also refer that the result of pancreatic fistula rate in our previous pilot study5 regarding PJ for pancreatic stump should be used to calculate sample size. Our previous study reported that PF occurred in 23.1% of the patients who underwent DP with PJ.5 However, all of 13 consecutive patients in the study prospectively underwent DP with en bloc celiac axis resection (DP-CAR) for locally advanced pancreatic cancer.6 The tumors indicated for DP-CAR often require the pancreatic transection on the right side of the portal vein. To transect the pancreas using a stapler device on the right side of the portal vein would increase the risk of pancreatic fistula. Therefore, the previous prospective study evaluated whether PJ in patients with DP-CAR decrease pancreatic fistula. The background of our previous study was completely different from that of this RCT, and the result in our previous study was not referred for this RCT, as DP-CAR often increase morbidity or mortality compared with standard DP.
The debaters suggest that dunking or invagination technique for PJ is better than duct-to-mucosa for nondilated duct at the resection site of the pancreas.